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SkipI 06-10-2003 03:41 PM

Starting problem.. 1989 C4
 
I am having a problem with my 89 vette. The engine takes anywhere from 5-8 seconds to start when cranking. Here is what I have done... new plugs, wires, fuel pump relay, dist. cap, rotor, and verified good timing. I have not checked fuel pressure because I don't want to spend $50 for a gage to use only once... instead, I jumpered the fuel pump on and cranked after 5 seconds of fuel pump run... no difference. I placed a timing light on the car and verified I had sparks while cranking... the light flashed fine. So, it is not the fuel pump, nor the spark plugs. I could place a test light on an injector to see if they are working? After it starts it purrs like a kitten all the time. It runs strong and without missing or any other problem. HELP!!

Thanks,
Skip

TheCorvetteKid 06-10-2003 03:55 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Skip, I am going through he EXACT same problem with my '89 as well. I've done vitually everything you've done as well as the fuel system pressure test, and I still haven't found the problem.

I am very VERY interested in your progress here - I have a feeling we can use the same solution!

Have you considered the IAC motor?

:lurk:


[Modified by TheCorvetteKid, 10:35 PM 6/10/2003]

88-406 06-10-2003 04:07 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
My 88 did this after I installed the MiniRam. The MiniRam doesn't use the 9th injector so I assumed it was because of that. Maybe there's some relavance to your car. Can you verify the 9th injector operation?

KM

SkipI 06-10-2003 04:38 PM

Re: Starting problem.. 1989 C4 (88-406)
 
The IAC motor is new... there is a funny story here... I took it out and left it connected. I turned the key on to see if it moved, but I was in diagnostic mode and the pintle shot across the garage. I decided to replace it after that!! My car does not have the cold start injector. I just replaced the intake manifold gasket and discovered there is no cold start injector. And yes, it was hard to start before I replaced the intake gasket.

TheCorvetteKid 06-10-2003 04:39 PM

Re: Starting problem.. 1989 C4 (88-406)
 
The '89-'91 L98s didn't have 9th injectors.

Skip, have you tried a compression test? I thought that was my problem, but my car tested great - 180psi-190psi across all cylinders. It's probably the same in your case, but it's good to rule out low compression.

But I've tried virtually everything to solve this (I've even replaced my injectors!!!) One thing you could try is to test the Coolant Temp Sensor on the front of the intake manifold. I tested mine this weekend, but the numbers looked OK (I saw 2.07Kohms@73degF). Also try disconnecting the MAF sensor and starting the car. If it starts OK, you've found your problem. Have you checked your TPS voltage? The manual says that if it's too high it can cause this condition (I tested THAT too this weekend and I got something like 0.49v with closed throttle; 4.45v at wide open throttle).

I'm thinking about just swapping out my ECM for a spare one that I have just to see if that does the trick. Someone suggested that it may be it.

This is one of those problems that you can ignore for years ('cause the car still runs fines) but it just EATS at you every time you get into the car and start it cold!


[Modified by TheCorvetteKid, 9:50 PM 6/10/2003]

SkipI 06-10-2003 04:54 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Thinking about the IAC motor... I disconnected it and started the engine and it made no difference. Just idled at higher RPM after cranking 5-8 seconds.

Skip

TheCorvetteKid 06-10-2003 04:59 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
I've never pulled my IAC, and for all I know is probably the original unit. I have a funny feeling that the secret might be with this sensor, but I don't know.

Why do you mention it? What are you thinking?


[Modified by TheCorvetteKid, 9:59 PM 6/10/2003]

SkipI 06-10-2003 05:04 PM

Re: Starting problem.. 1989 C4 (TheCorvetteKid)
 
I don't think I have a compression problem with only 46,000 miles on the car. The coolant temp sensor was replaced when I replaced the intake manifold gasket (when I work around a sensor, I replace it since they are 14 years old). I adjusted the TPS when I put everything back together. I started the car with the MAF diconnected and got the same thing.

Skip

John Row 06-10-2003 06:21 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
I think there was another very similar thread in the past couple of weeks. I don't recall what year, but the problem was an oil pressure bypass. The engine wouldn't start till there was sufficient oil pressure. This bypass held the circuit closed for something like 5 seconds to give the engine a chance to start.

TheCorvetteKid 06-10-2003 11:34 PM

Re: Starting problem.. 1989 C4 (John Row)
 

I think there was another very similar thread in the past couple of weeks. I don't recall what year, but the problem was an oil pressure bypass. The engine wouldn't start till there was sufficient oil pressure. This bypass held the circuit closed for something like 5 seconds to give the engine a chance to start.
I've read somewhere that there was a batch of bad oil pressure switches that where used in production for 88-89 or so. There were enough of them that they stayed in the spare parts stream for a few years too. I also remember something about being able to tell whether you have one of the suspect units by it's color, but I don't remember what that color was. Anybody out there know anything about this? Pics would help too.

jfb 06-11-2003 12:35 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
You spent money to replace (new plugs, wires, fuel pump relay, dist. cap, rotor), without knowing if they needed replacing, but you are too cheap to buy a fuel pressure gauge to tell you if you have a leaky fuel injector? You aren't thinking clearly. A common cause of hard starting is a leaky fuel injector which can be found by putting a fuel pressure gauge on the shrader valve on the fuel rail, turn the ignition on for several seconds to pressurize the rail, turn off the ignition and see how long it takes to lose 1 psi. GM says it must take more than 30 minutes or you have a leaking injector.

loflyin 06-11-2003 12:53 PM

Re: Starting problem.. 1989 C4 (TheCorvetteKid)
 
Good oil pressure switch is black, bad batches were gray. Saw this at http://www.C4vettes.com - hope it helps. I have the same problem, but now it won't start at all and fuel pump not running unless I charge it through the ALCL. If you figure it out, please share. Thanks.

TheCorvetteKid 06-11-2003 12:55 PM

Re: Starting problem.. 1989 C4 (jfb)
 
Hey jfb, while agree with you that a fuel pressure test guage is a useful tool, I bought mine to diagnose the same problem and my fuel system shows to be OK. I would suggest that Skip gets a guage as well, but replacing plugs, wires, pump relay, distributor cap and rotor is just good routine maintenance - you can't fault a guy for that.

Regardless, my car HAD a leaky injector when I first bought it and while the symptom of a hard-start is the same, it only happened when the car was hot. When the car was cold, it started up fine. And this is VERY much in line with what alot of other people on this forum have said. Makes sense when you think about it - when an engine is cold, it likes a slightly richer mix of air/fuel to get started, but when it's hot it creates a flooding condition causing the hard starting problem.

But lets assume that Skip bites the bullet and buys a fuel pressure test guage and finds that his fuel system is OK (as I did) - what do you suggest he ("we" really since we have the same problem) try next?

SkipI 06-11-2003 05:51 PM

Re: Starting problem.. 1989 C4 (jfb)
 

You spent money to replace (new plugs, wires, fuel pump relay, dist. cap, rotor), without knowing if they needed replacing, but you are too cheap to buy a fuel pressure gauge to tell you if you have a leaky fuel injector? You aren't thinking clearly. A common cause of hard starting is a leaky fuel injector which can be found by putting a fuel pressure gauge on the shrader valve on the fuel rail, turn the ignition on for several seconds to pressurize the rail, turn off the ignition and see how long it takes to lose 1 psi. GM says it must take more than 30 minutes or you have a leaking injector.
Okay, here is how I justified not getting the gage. I replaced the plugs, wires, cap & rotor due to age. When I replaced the plugs, there were no plugs with gas on them or the smell of gas.... I would think this would eliminate leaking injector. Regardless, when I jumped the fuel pump on via the ALDL for 5 seconds before starting the car, it still took excessive cranking. I would think this would eliminate low fuel pressure on the rails via leaking injector or bleeding back through the fuel pump? It is not so much that I am cheap... just that I figured I could eliminate the need for a gage by doing other tests.

Skip

SkipI 06-11-2003 05:54 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Update.... today after work when I got into the car, I barely had to touch the key for the engine to fire. It had not started this fast in some time! When I got home I turned the engine off and when I restarted it... yep, you guessed it, it took excessive cranking!! :crazy: You just got to love this!! Anyways, the problem is random and not each time. I throw this in to add confusion to the troubleshooting!!

I do appreciate all the replies guys!! :thumbs:

Thanks,
Skip


[Modified by SkipI, 10:55 PM 6/11/2003]


[Modified by SkipI, 10:55 PM 6/11/2003]

SkipI 06-11-2003 06:01 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Hey... what about this.... this was on a corvette service bulletin...

Component: FUEL:FUEL INJECTION SYSTEM
Summary: INTERMITTENT NO START, LONG CRANK, STALL, OR ENGINE SURGE-BOTH MAF RELAYS(BURN O FF AND BURN OFF CONTROL)SHOULD BE REPLACED-1988/89 CORVETTE DG

Anyone replace these relays to fix this??

Skip

TheCorvetteKid 06-11-2003 06:17 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
I've heard of people replacing the two MAF relays but I don't know if it helped at all. I never considered them because I know that my burn-off relay works cause I can hear it buzz for a second after I drive the car.

But it's worth a shot seeing as they aren't much money.

Frodo 06-11-2003 06:38 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
I've been following this thread, and others like it, since I have the same problem with my 89 coupe. Before rebuild it started quickly, cold or hot. After rebuild, cold takes 10 seconds or more of cranking before it fires, 5 seconds or more when hot. I built it up stock except I added headers, Bosch 21# injectors, eliminated AIR and EGR. All sensors are new, IAC is new, fuel pressure is 42# with new AFPR but it drops significantly in an hour. Once, as a test, I removed plenum and fuel runners then I loosened and lifted the fuel rails with injectors intact but left the fuel lines connected. I turned on ignition to charge the fuel rails and looked for injector leaks... all 8 remained dry. So... no leaky fuel injectors. Timing is 6 degrees before TDC, as per sticker in engine compartment. Once cranked it idles and runs fine except it has an intermitten skip at idle that seems like an ignition problem. Acceleration is strong. Fuel milage is 3 to 5 MPG less than before rebuild. I'd sure like to find what's causing this hard cranking condition.

TheCorvetteKid 06-11-2003 06:58 PM

Re: Starting problem.. 1989 C4 (Frodo)
 
Frodo, have you considered the two MAF relays?

It sounds to me like you've tried virtually everything else. Like I said above, for the cost and effort it's worth a try.

jfb 06-11-2003 10:55 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Wet plugs don't always show up with a leaking injector. When the air/fuel is way too rich, the engine won't start easily. Also, your problem is intermittent and looking ONCE doesn't prove you don't have a leaky injector. And, a leaky injector also doesn't necessarily lower the fuel pressure, so your test by turning on the fuel pump for 5 seconds isn't conclusive. Spend the money and prove beyond the shadow of doubt by actual fuel pressure measurement that your injectors are or are not leaking.
Check your initial spark timing, and check each spark plug wire with your timing light to prove that each plug is firing. A vacuum leak will make it hard to start. Measure your manifold vacuum, look for vacuum leaks on ALL of your vacuum lines. Do you have any stored error codes? Check them. What is your TPS (throttle position sensor ) voltage? A stuck EGR valve can cause too low air/fuel ratio during cranking and hard starting. A defective MAF sensor can cause hard starting, try disconnecting it and attempt a start. Put a low power 12v lamp across each injector socket and observe that each is being pulsed when you crank the engine. Let us know what you find.

SkipI 06-12-2003 07:37 AM

Re: Starting problem.. 1989 C4 (jfb)
 

Wet plugs don't always show up with a leaking injector. When the air/fuel is way too rich, the engine won't start easily. Also, your problem is intermittent and looking ONCE doesn't prove you don't have a leaky injector. And, a leaky injector also doesn't necessarily lower the fuel pressure, so your test by turning on the fuel pump for 5 seconds isn't conclusive. Spend the money and prove beyond the shadow of doubt by actual fuel pressure measurement that your injectors are or are not leaking.
Check your initial spark timing, and check each spark plug wire with your timing light to prove that each plug is firing. A vacuum leak will make it hard to start. Measure your manifold vacuum, look for vacuum leaks on ALL of your vacuum lines. Do you have any stored error codes? Check them. What is your TPS (throttle position sensor ) voltage? A stuck EGR valve can cause too low air/fuel ratio during cranking and hard starting. A defective MAF sensor can cause hard starting, try disconnecting it and attempt a start. Put a low power 12v lamp across each injector socket and observe that each is being pulsed when you crank the engine. Let us know what you find.
Timing was previously checked good. The throttle position sensor was checked and was 0.58 volts. I replaced the EGR valve when I replaced the intake manifold gasket a couple of months ago. I have a hand pump and tested all the vacuum lines and none of them dropped vacuum rapidly. Starting the engine with the MAF disconnected made no difference. I'll check all plugs with the timing light. I do not have the SES light on, I am sure I have stored codes since I have been disconecting things and starting the engine. I'll reset the codes and look later. I thought about putting the light on the injectors, but don't have a light yet. I am thinking about taking the car into the shop and letting them diagnose the problem and giving it back to me to fix. I would REALLY like to have a scan tool so I can see what is going on when the engine is starting. The service manual has a table to compare the data against. Thanks for the info... I do some more data gathering and get back with you... time to get a gage.

Skip

TheCorvetteKid 06-12-2003 08:00 AM

Re: Starting problem.. 1989 C4 (SkipI)
 
Skip, don't feel bad about getting a fuel pressure guage. I know you're probably thinking "I've spent enough money and time on this stupid problem" but believe me, you will find that the guage is actually quite useful for more than just this problem.

jfb 06-12-2003 10:37 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Intermittent hard starting can also be caused by a spark control module. I had that problem and replaced it.

TheCorvetteKid 06-12-2003 10:52 PM

Re: Starting problem.. 1989 C4 (jfb)
 

Intermittent hard starting can also be caused by a spark control module. I had that problem and replaced it.
How would you test for something like that?

jfb 06-13-2003 01:24 AM

Re: Starting problem.. 1989 C4 (TheCorvetteKid)
 
Some auto parts stores can test spark modules, but since you have an intermittent problem, and who knows what the tester is looking for, I would recommend installing a new one since they aren't very expensive. When mine was giving me trouble, about 80% of my starts were long cranks.

SunCr 06-13-2003 01:24 AM

Re: Starting problem.. 1989 C4 (SkipI)
 
My '89 was a hard start (cold) from the factory. Fuel pressure was normal - An injector balance test was normal (yeah I bought the tool that pulses each injector so you can note the pressure drop on your gauge) - and I replaced a ton of stuff over the years trying to improve it. Finally put in new injectors (Accels) and it fires right up. I even had Rich at Cruzin Performance look at the old ones and he couldn't find anything wrong with them. Go figure.

SkipI 06-13-2003 07:48 AM

Re: Starting problem.. 1989 C4 (jfb)
 

Some auto parts stores can test spark modules, but since you have an intermittent problem, and who knows what the tester is looking for, I would recommend installing a new one since they aren't very expensive. When mine was giving me trouble, about 80% of my starts were long cranks.
You are talking about the module in the distributor and not the one by the blower fan, right??

Skip

jfb 06-13-2003 08:47 AM

Re: Starting problem.. 1989 C4 (SkipI)
 
Yes, I am talking about the module in the distributor that pulses the spark coil.

blackvette89 06-13-2003 06:04 PM

Re: Starting problem.. 1989 C4 (SkipI)
 

I am having a problem with my 89 vette. The engine takes anywhere from 5-8 seconds to start when cranking. Here is what I have done... new plugs, wires, fuel pump relay, dist. cap, rotor, and verified good timing. I have not checked fuel pressure because I don't want to spend $50 for a gage to use only once... instead, I jumpered the fuel pump on and cranked after 5 seconds of fuel pump run... no difference. I placed a timing light on the car and verified I had sparks while cranking... the light flashed fine. So, it is not the fuel pump, nor the spark plugs. I could place a test light on an injector to see if they are working? After it starts it purrs like a kitten all the time. It runs strong and without missing or any other problem. HELP!!

Thanks,
Skip
my 89 had similar cold start problem. i literally went thrugh a starter. after replacing uel pump,temp sensor (controls air/gas ratio) iac, relays, the problem was the ecm itself and it threw no codes. i haven't had the problem since! i hope you find it, i know your frustrations. :flag

TheCorvetteKid 06-13-2003 06:42 PM

Re: Starting problem.. 1989 C4 (blackvette89)
 

My 89 had similar cold start problem. I literally went thrugh a starter. after replacing fuel pump, temp sensor (controls air/gas ratio) IAC, relays, the problem was the ECM itself and it threw no codes. I haven't had the problem since! I hope you find it, I know your frustrations.
That's why I want to try and swap-out my ECM to see if it solves my problem (I don't need to start replacing starter motors).

When you replaced your ECM, did you replace the MemCal (the chip) as well? I have a spare ECM for my car, but it doesn't have a MemCal unit - I'm supposed to reuse the one that's in ECM in the car now.


[Modified by TheCorvetteKid, 5:47 PM 6/13/2003]

blackvette89 06-13-2003 11:09 PM

Re: Starting problem.. 1989 C4 (TheCorvetteKid)
 
i used my old prom. so far it starts every shot. only problem is my fan only comes on at 236. i've been asking around for input on if this is normal. it used to come on at 228! or so. how bout yours?? :cheers:

jfb 06-14-2003 12:24 AM

Re: Starting problem.. 1989 C4 (blackvette89)
 
The factory prom turns on the fan at 228 F. 236 might just be a sensor error.
It looks like you found the problem, the ECM.

89convt 06-14-2003 09:47 AM

Re: Starting problem.. 1989 C4 (SkipI)
 
I had asimilar problem on my 89 with an intermittent hard start and failure to start at times. Replaced most of parts mentioned here and finally the ecm. Solved the problem and hasn't missed a lick for over a year. Good luck. You should see if the injectors are being pulsed during the first 5 seconds of cranking but not starting. If not ecm could be the source of your frustration. :)

blackvette89 06-14-2003 01:55 PM

Re: Starting problem.. 1989 C4 (jfb)
 
i bought a low temp sensor on at 200 off at 185 i'm goona see if it does the trick! i'll keeo you posted. just to be sure, this sensor is located on pas side of block?? :cheers:

TheCorvetteKid 06-15-2003 12:58 AM

Re: Starting problem.. 1989 C4 (blackvette89)
 

I bought a low temp sensor on at 200 off at 185 i'm goona see if it does the trick! I'll keeo you posted. Just to be sure, this sensor is located on pas side of block?? :cheers:
Hey blackvette89, the temp sensor that controls when the fan comes on and off is the one on the intake manifold on the front of the engine (just below the throttle body). It feeds the information to the ECM; it's the ECM that turns the fan on and off. The sensors on the heads are used for other things. One is used for the gauge display on the dash, and the other is used to turn on the boost fan in front of the rad (I forget which of the sensors does what though).

It's funny that you mention this problem actually 'cause my car started doing the same thing. I still haven't tried to swap out my ECM to see if it cures my hard starting problem (I have a few other issues with the car that I am trying to address first) but after I took the heads off to change the headgaskets, I noticed that my fans have also beem coming on later than before. And at the same temps that you mention too. Funny thing is, I've checked my existing temp sensor and it seems fine. Hmmm...makes me wonder what this could be.


[Modified by TheCorvetteKid, 12:00 AM 6/15/2003]

SkipI 06-17-2003 12:46 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
As troubleshooting continues... I have noticed that when I attempt to start the engine and stop cranking before it starts, every time I begin my second attempt, the engine starts immediately. The new ignition module made no difference.

Skip

TheCorvetteKid 06-17-2003 12:56 PM

Re: Starting problem.. 1989 C4 (SkipI)
 

As troubleshooting continues... I have noticed that when I attempt to start the engine and stop cranking before it starts, every time I begin my second attempt, the engine starts immediately. The new ignition module made no difference.

Skip
Skip, I found the same thing with my car too. This is like history repeating itself - I've done all the things you are trying and nothing has solved the problem.

I guess there's only 2 things it can be: either the oil pressure switch or the ECM. Even though I have a spare ECM at home, I have the valve covers off and the rocker arms out of my car right now so I can't even swap out my ECM just to try; consequently changing the oil pressure switch wouldn't do any good either right now.

The oil pressure switch is fairly inexpensive and not too difficult to change (it's right next to the distributor and bolts straight into the top of the engine block). A rebuilt ECM is about $99-$150 from MidAmerica and is a worthwhile thing to have even if your current one is actually OK.

Continue with the diagnosis. All us hard-starting '89 owners are watching and waiting...

John Row 06-17-2003 01:12 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
If it is annoying enough, maybe a call to Gordon Killebrew is in order.
http://www.gordonkillebrew.com/pages/800737/index.htm

SkipI 06-17-2003 02:17 PM

Re: Starting problem.. 1989 C4 (TheCorvetteKid)
 

I guess there's only 2 things it can be: either the oil pressure switch or the ECM. Even though I have a spare ECM at home, I have the valve covers off and the rocker arms out of my car right now so I can't even swap out my ECM just to try; consequently changing the oil pressure switch wouldn't do any good either right now.
Here is how, in my mind, the oil pressure switch is not the cause. The oil pressure switch, in accordance with the service manual, is used to run the fuel pump. I applied 12+ to the ALDL connection for the fuel pump, verified it running, and started the car. Same long crank. Since the ECM does not use the oil pressure switch for anything else, the oil pressure switch should not be the problem? :confused: So, I am looking at replacing the ECM. Update to follow......


jimmyd 06-17-2003 05:20 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
I have the same problem also, car is a 88, Just put new motor in and it still is hard to start when hot. when cold it fires instantally. I've put one of the small fuel pressure gauges on and it stays hooked up all the time. It does show a presure drop, so I guess new injectors are in order,
:banghead: :banghead: :banghead: :mad

blackvette89 06-17-2003 05:45 PM

Re: Starting problem.. 1989 C4 (TheCorvetteKid)
 
i'll let u know how i make out with that new sensor. thanks for the input. i was told by a gm guy that the sensors sometimes increase or decrease the oohm to the ecm changing the on off temp. this is a sign to replace. funny that we have the same temps though. i feel less beaten up by my 89!!!!!!!!!

I bought a low temp sensor on at 200 off at 185 i'm goona see if it does the trick! I'll keeo you posted. Just to be sure, this sensor is located on pas side of block?? :cheers:

Hey blackvette89, the temp sensor that controls when the fan comes on and off is the one on the intake manifold on the front of the engine (just below the throttle body). It feeds the information to the ECM; it's the ECM that turns the fan on and off. The sensors on the heads are used for other things. One is used for the gauge display on the dash, and the other is used to turn on the boost fan in front of the rad (I forget which of the sensors does what though).

It's funny that you mention this problem actually 'cause my car started doing the same thing. I still haven't tried to swap out my ECM to see if it cures my hard starting problem (I have a few other issues with the car that I am trying to address first) but after I took the heads off to change the headgaskets, I noticed that my fans have also beem coming on later than before. And at the same temps that you mention too. Funny thing is, I've checked my existing temp sensor and it seems fine. Hmmm...makes me wonder what this could be.


[Modified by TheCorvetteKid, 12:00 AM 6/15/2003]
:cheers:

SkipI 06-17-2003 06:42 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
:mad :mad :mad :mad
Well, I have a new AC Delco ECM and oil pressure sender/switch assembly and still long start! :lol: I did, however fix three things that were bothering me... 1. My oil pressure is 6-8 psi higher with the new switch... I like 23 PSI at idle a lot more than 15 psi. 2. The car goes to idle speed better now. The engine warms up a little and drops to 600 rpm. Before, I'd have to drive the car somewhere and when it got warm, sit stopped for 10-15 seconds and the idle would drift down to 600. 3. I had to remove the wiper motor to get a socket on the oil pressure sender (wish I'd replaced that when I replaced the intake manifold gaskets!) and when I put the wiper motor back on, I adjusted the wipers so they don't hit the windshield frame anymore. Oh well... the search sorta continues... I am out of budget for a little while. Maybe a new coil? :lol: There is ALWAYS something to spend $$$$ on!! You know, they say that a boat is a hole in the water that you throw money into... and they are made out of fiberglass also?! :skep:

ONEBAD89 06-17-2003 08:51 PM

Re: Starting problem.. 1989 C4 (Frodo)
 
Same exact problems here, with my 89 coupe. They only started after I removed and rebuilt the motor and replaced. Hard satrt-ups when cold and so-so when heated up, but only after the rebuild. Replaced everything under the sun from sensors to ignition, some twice. After all I replaced the ecm, car started great hot or cold for about 3 weeks, now back to ground zero with hard start-ups again, not to mention that she likes to try and stall from time to time when hard breaking around a bend. Not sure if I should just replace the ecm again, had a L.T. warranty or look for something else first. Good luck with yours and I'll keep trying here. Later!
FRED

TheCorvetteKid 06-18-2003 01:52 PM

Re: Starting problem.. 1989 C4 (ONEBAD89)
 
Skip, Someone here at work suggested a new coil too. In fact, when I first bought my car, it had an Accel HEI Super Coil and I don't remember it giving me a problem starting. But, I only had the coil on the car for like a day - I hated the way the thing looked and I bought a new Delco unit and replaced it myself (along with a new cap, rotor, plug wires, and plugs). In fact, the guy here at work said to put the Accel coil back on the car and see if that makes a difference. If so, then BINGO! new coil needed (I've heard that Delco HEI coils have a WIDE variation in their outputs - even when new).

But it'll have to wait until this weekend for me. I'm still waiting on my new pushrods so that I can put the engine back together (should be in tomorrow night).

blackvette89 06-18-2003 04:14 PM

Re: Starting problem.. 1989 C4 (TheCorvetteKid)
 
HEY I WAS HOPING IT WAS YOUR ECM LIKE MINE. I DEFINETLY KNOW YOUR FRUSTRATIONS. ITS NOT EVEN THE MONEY ITS THE DIAGNOSIS AND GET IT OVER WITH. I'M GONNA TALK WITH A GM GUY I KNOW AND LET HIM READ YOUR POSTS.I'LL UPDATE YOU! I DID REMEMBER HIM TALKING ABOUT POSSIBLE COILS WHEN HE WAS BRAINSTORMING MY PROBLEM. DIDYOU REPLACE THE AIC? :confused:

blackvette89 06-18-2003 04:19 PM

Re: Starting problem.. 1989 C4 (TheCorvetteKid)
 
HEY CORVETTE KID, I HAD TO REORDER THAT LOW TEMP SWITH. IT WAS OUT OF STOCK. WHEN I GET IT I WAS TOLD I HAVE TO REWIRE BECAUSE I DON'T HAVE AN AUXILLARY FAN. CAN YOU GIVE ME A HEADS UP TO THE PROJECT. THANKS TOM :confused:

SkipI 06-18-2003 04:49 PM

Re: Starting problem.. 1989 C4 (blackvette89)
 

HEY I WAS HOPING IT WAS YOUR ECM LIKE MINE. I DEFINETLY KNOW YOUR FRUSTRATIONS. ITS NOT EVEN THE MONEY ITS THE DIAGNOSIS AND GET IT OVER WITH. I'M GONNA TALK WITH A GM GUY I KNOW AND LET HIM READ YOUR POSTS.I'LL UPDATE YOU! I DID REMEMBER HIM TALKING ABOUT POSSIBLE COILS WHEN HE WAS BRAINSTORMING MY PROBLEM. DIDYOU REPLACE THE AIC? :confused:
Do you mean the IAC? Yep... it is fairly new also... the only thing that makes me wonder about it however, is that it can be heard when turning the engine off as it repositions. I do not remember hearing the old one. But, the engine idles great.

Skip

SkipI 06-18-2003 04:55 PM

Re: Starting problem.. 1989 C4 (SkipI)
 

HEY I WAS HOPING IT WAS YOUR ECM LIKE MINE. I DEFINETLY KNOW YOUR FRUSTRATIONS. ITS NOT EVEN THE MONEY ITS THE DIAGNOSIS AND GET IT OVER WITH. I'M GONNA TALK WITH A GM GUY I KNOW AND LET HIM READ YOUR POSTS.I'LL UPDATE YOU! I DID REMEMBER HIM TALKING ABOUT POSSIBLE COILS WHEN HE WAS BRAINSTORMING MY PROBLEM. DIDYOU REPLACE THE AIC? :confused:
I am also thinking about replacing the coil since they are fairly inexpensive. I am still confused at the fact that it starts rapidly when I get in the car at work to go home. Today was the 4th time in a row that the car started quickly at work. I do not know if sitting out in the sun has anything to do with it.... I cannot see how that would affect anything since everything under the hood is hot when I get home and try to start it. That was part of my replacing the ECM logic... maybe since the interior of the car is hot, it is affecting the ECM... but that was not it. Still wondering....

Skip

TheCorvetteKid 06-18-2003 09:20 PM

Re: Starting problem.. 1989 C4 (blackvette89)
 

HEY CORVETTE KID, I HAD TO REORDER THAT LOW TEMP SWITH. IT WAS OUT OF STOCK. WHEN I GET IT I WAS TOLD I HAVE TO REWIRE BECAUSE I DON'T HAVE AN AUXILLARY FAN. CAN YOU GIVE ME A HEADS UP TO THE PROJECT. THANKS TOM :confused:
Hi Blackvette89 (funny, my '89 is black too). I'd be more than happy to help where I can, but my car already has the boost fan. Besides, I'm still running the stock sensor. But now that you've mentioned the change in Ohm value that can occure with old coolant sensors, I think I'll pay my GM dealer a visit tomorrow at lunch and pick up a new one too.

BTW, where did you get the low-temp sensor anyway (Ecklers, MidAmerica, etc...)? They usually have pretty good instructions that come with their kits. But either way, let me know I'll help wherever I can.

csc67 06-18-2003 10:05 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Have had a extended crank time on my 1989 for over one year (although this only occurs when the car has been sitting for over 6 hours - if warm it starts fine). Are any of you folks getting a code 54 ?? From all of the reading I've been doing it comes down to many items; injectors, ECM, fuel pump, fuel pump relay, fuel pump fuse, bad ground. Someone just call Gordon and pass on the informatin to us LOL

ONEBAD89 06-18-2003 10:05 PM

Re: Starting problem.. 1989 C4 (TheCorvetteKid)
 
I have a fairly new accel hei super coil, but after speaking with some other engine/motor friends they informed me that the accel line was all junk and to go with msd. So now I am ordering a complete kit, cap rotor, coil and msd wires, I believe it also includes a new HEI module. Supposed to provide a potent spark signal to 9000 rpms. Going to add that along with the MSD 6AL to complement the spark. Give that a try to see if it works........

csc67 06-18-2003 10:06 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Have had a extended crank time on my 1989 for over one year (although this only occurs when the car has been sitting for over 6 hours - if warm it starts fine). Are any of you folks getting a code 54 ?? From all of the reading I've been doing it comes down to many items; injectors, ECM, fuel pump, fuel pump relay, fuel pump fuse, bad ground. Someone just call Gordon and pass on the information to us LOL

SkipI 06-18-2003 10:46 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
New coil didn't fix it either. You know, if you built a corvette from parts, it would cost ____. I'll fill in the number later!! :lol:

TheCorvetteKid 06-18-2003 10:51 PM

Re: Starting problem.. 1989 C4 (SkipI)
 

New coil didn't fix it either. You know, if you built a corvette from parts, it would cost ____. I'll fill in the number later!! :lol:
If you built a C4 from scratch - assuming you could actually GET everything from GM before they discontinued it - it would probably cost $300,000! And that's assuming we are talking about an L98/LT1/LT4 car. If it where a ZR-1?...then I don't even want to harbour a guess. :lol:

ONEBAD89 06-18-2003 11:21 PM

Re: Starting problem.. 1989 C4 (TheCorvetteKid)
 
Although, as I mentioned earlier in another similar post, I replaced my ecm with a new one and the car started, idles and ran perfect for about 2 weeks, then back to same old hard start-ups, especially when cold and rough idle, tries to stall when breaking hard or at idle.

P.S. My 89 vette is also black.



[Modified by ONEBAD89, 4:23 AM 6/19/2003]

NanoBrain 06-19-2003 06:36 AM

Re: Starting problem.. 1989 C4 (ONEBAD89)
 
Hey can I join this Black 89 club?

Anyway, here’s one from the left field! 1989’s, and I would guess the 88’s, have a temp sensor mounted under the drivers side dash area. It’s sole purpose is to aid the ECM when starting at, or near below freezing temps. Now, as we already know from experience, when a sensor goes bad it can freak out, or even damage the ECM.
So, here’s my wild guess: Possibly this sensor has degraded over the last 14-15 years, and is causing the ECM problems?

This sensor is probably cheap, and it would be an interesting experiment for all of the others out there with this problem! Who knows maybe I’m just:crazy:!

:crazy:NanoBrain:crazy:

TheCorvetteKid 06-19-2003 08:31 AM

Re: Starting problem.. 1989 C4 (NanoBrain)
 
Wait a sec! There's a temp sensor under the driver's side dash? Why is this the first I'm hearing of this?

Nano, you may have a good point! Anybody try this one? I'll check my Service manual when I get home tonight. If it's not that difficult a job, then it may be worth a try.

Ray Quayle 06-19-2003 10:45 AM

Re: Starting problem.. 1989 C4 (TheCorvetteKid)
 

Wait a sec! There's a temp sensor under the driver's side dash? Why is this the first I'm hearing of this?
Because he made it up! :bs

He may be talking about the Ambient Over-ride Sensor, but that's for the Digital Dash, not the ECM.

blackvette89 06-19-2003 03:41 PM

Re: Starting problem.. 1989 C4 (Ray Quayle)
 
:bs
i definetly know for a fact there is no sensor there. not on mine. hopefully an honest mistake :iagree:

MtlSphere 06-19-2003 04:13 PM

Re: Starting problem.. 1989 C4 (blackvette89)
 
Nah...you boys got it all wrong...

The problem is quite obvious after reading all of the posts...what's the constant in all of these cars?

They're all BLACK!

Sure, there are other colors besides RED, ... But who cares? :reddevil

Just messin' with ya fellas. I'm on vacation and have waaaaaay too much time on my hands! Think I'll go for a drive! Good luck! :cool:

ONEBAD89 06-19-2003 10:19 PM

Re: Starting problem.. 1989 C4 (blackvette89)
 
The new ecm fixed my problem but only for a couple weeks, back to ground zero, any other suggestions??? :confused:
Thanks for the replies.............

FRED

NanoBrain 06-20-2003 08:03 AM

Re: Starting problem.. 1989 C4 (ONEBAD89)
 
Ooops My Bad:bb! You’re correct about the Sensor I referred to earlier; it’s for the Digital Cluster, not the ECM. I read about this Sensor/switch many years ago, so the details and facts got a little fuzzy for me, sorry:(.

The item’s name is actually “Ambient Temperature Override Switch”, sounds like a bi-metallic switch to me. What I would like to find out is, it’s real purpose! Does it modify the LCD drive/contrast voltage for low temps, or does it enhance the Cluster’s Micro-Controller/Oscillator Clock stability at low temps? In any case, it’s probably a long shot that it would affect starting.

But perhaps my technical foul has led me down a different path! In my Service manual it states under the Digital Cluster section “If the Digital Cluster is intermittent and the engine misses, check for bad Capacitor ground or a bad Capacitor at the Generator.” & “ Check for a bad Tachometer Filter.” The “engine misses” has got me thinking about EMI/RFI on the digital signal circuits.

What if the ECM/Digital Cluster/ALDL Serial data path was intermittently corrupted by noise generated from any number of items (Digital Cluster, Alternator, AC Clutch, Starter Motor, Emissions Solenoids/Servos, Etc) on the vehicle?

I pose this concept only as a shot in the dark, as it sound like you guys have already R&R’ed the usual suspects.

This is just grasping at straws, because it’s a slim chance that someone has a Digital Bus Signal Analyzer at home. Trying to find corrupted bits/bytes/hand shakes, or quantitative analysis of clock jitter is a little out of scope for most of us. As a consolation prize, the cure may be as simple as replacing a few filter caps on the DC power/charging system, or on the signal lines, or perhaps getting a rebuilt ECM/Cluster. Who knows, maybe it’s an intermittent ground failure somewhere; after all, the Y-body is notorious for having ghost problems created by bad grounds:rolleyes:!

As a side note, the Service manual also said something about an “in Tank, Fuel Pump Check Valve” as causing hard starts. If this device fails, it causes the fuel to siphon back into the Tank when the car sits for a while. I wonder, a few of you said you thought you had good FP upon cranking, but what if the initial pressure was compressed air after the Pump re-primed? The Fuel lines would purge them selves through the Injectors/return line, within ten seconds of cranking right?

Anyway, sorry I sounded like I was talking out of my butth0le; I also hate disinformation:mad. I really hate being the source of it- Doh:banghead:!

PS, I told you I might be:crazy:!

:crazy:NanoBrain:crazy:


[Modified by NanoBrain, 1:07 PM 6/20/2003]

SunCr 06-20-2003 12:24 PM

Re: Starting problem.. 1989 C4 (NanoBrain)
 
As best as I can tell, the ambient air override switch is in the cruise circuit; closing at 32 degrees, which I think is a signal to the display to disable cruise control below freezing temps. It's function isn't described in the Shop Manual or in Killebrew's Digital Dash repair manual, but it is shown in the cruise circuit and it indicates that it closes at the above temperature, so that's my best guess. It doesn't get cold enough here for an actual test - so other than disconnecting the blue wire and providing a ground, I have no way of testing it to see if it works this way. As to the cold start, this seems to be a fuel issue only - too little; especially since after cranking it and stopping and then cranking again produces an immediate start. Try priming the rail a few times with the key on and off with no crank and then see if it starts. If so, pressure isn't high enough to give it the squirt it needs to fire when cold which could be the filter, the pump (including it's electrical circuit), the regulator, or the injectors. Seriously doubt that all these hard starting '89's have too narrow of a cold start pulse width programmed into the chip, but maybe someone over in tuning could give us a heads up. I'd also make sure that the TPS signal is at specs along with minimum idle and that timing is deadon at 6 BTDC.

jfb 06-20-2003 12:31 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
I think you have defective injectors whose internal solenoid valve is sensitive to temperature. You start ok at work because the car sits for 8 hours at daytime temperatures and when you start it, the engine is at a higher temperature than when it sits all night at a lower temperature. Starts in the morning are at a cooler engine temperature because it sat longer and in lower temperatures. A leakdown test after work and a leak down test in the morning might show faster leak down in the morning. You have a fuel pressure gauge now, give it a try.

NavyVet 06-20-2003 02:14 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Can I play too? My '89 is a black Z51 6Spd coupe. Long cranking before start and it defies detection! What I've done so far:

New plugs, coil, cap, rotor - stock type
New battery & alternator - probalby wore out cranking too long :)
New coil, cap & rotor - DUI (have a near new stock set on the shelf now)
New fuel pump & screen - old one is available & works fine
New fuel filter (improved fuel delivery, but still cranks a long time)
New injectors & AFPR (holds pressure fine - same long start all pressures)
New plug wires - Taylor 8mm
New IAC & TPS (properly adjusted per Helms manual)
New throttle body
New temp sensors

Once started - runs geat, never misses, stalls, etc.

Maybe it is a black thing :D


[Modified by NavyVet, 12:15 PM 6/20/2003]

SunCr 06-20-2003 03:37 PM

Re: Starting problem.. 1989 C4 (NavyVet)
 
How frustrating! You've replaced all most everything and still no solution! If it's a hard start both hot and cold, use the code 54 chart to check the ECM driver and relay. Also, make sure the pump continues to run while cranking and isn't shutting down (with a hose attached to the inlet line & in a gallon jug, crank it over . Did you flush the inlet when you replaced the filter? The fact the flow improved could mean that some junk was past the filter. Best to clamp a hose to the inlet at the rail and then cycle the pump a couple of times to be sure its clean. Otherwise, crap can find it's way into the new injectors. Make sure injector resistance is 10 ohms or better hot & cold and that all are the same. Make sure the EGR is closed. Otherwise, I guess our '89's suffer from some sort of design malady. Mine was a hard start new and a cheapo set of Accel injectors solved it. Along the way, I've replaced the heads, rebuilt the fuel rail, throttle body and changed out the filter and every sensor, all modules, and the ECM was replaced twice under the factory warranty. In fact, about the only mechanical things I haven't replaced in 56,000 miles are the short block, tranny, diff, shocks & fuel pump - but dammit at least it now starts right.

ONEBAD89 06-21-2003 09:55 AM

Re: Starting problem.. 1989 C4 (SunCr)
 
Like I mentioned earlier, I too replaced all that NavyVet replaced and then some. I also have new bosch injectors and have tested the fuel pressure, it drops over night but when you turn the key it jumps right up to 42 psi where I have it set. Same starting problem, really tough in the am, not so bad after work on a warm day. Thing was a new rebuilt ecm fixed the problem for about 2 weeks then same problem came back. The new ecm mentioned something about one needing to test all sensors, if any were bad they would corrupt the the ecm which I believe happened to mine. Try replacing the ecm to see if it helps, there under $100 at the local store, plus if you buy from the right place you get a LT warranty with, like me. Good Luck, will be reading to see if I can find out what caused my ecm to go bad. Later!
FRED
89' Black L98 Owner & Frustrated :confused:

SunCr 06-21-2003 08:05 PM

Re: Starting problem.. 1989 C4 (ONEBAD89)
 
Your ECM may not be bad, but something else, that possibly shares the same driver as the FP or injectors may be acting up causing the driver to shut down. It's kinda like a built in circuit breaker - so the ECM doesn't fry. Unfortunately, other than to tell you that the ECM has this protection, GM doesn't tell you what the shared components are for each driver, if any. The tune and scan guys may have the knowledge to point you in the right direction.

SunCr 06-21-2003 11:06 PM

Re: Starting problem.. 1989 C4 (SunCr)
 
I checked the fuel pump circuitry and the common element is the power feed which is shared with the MAF, both MAF relays and the oil pressure sender, all off of the main power feed from the battery to the ECM. You might want to check this circuit or the MAF components. High circuit resistance or perhaps a faulty relay? Might be worth looking at or see what data you can capture with a scanner while cranking.

TheCorvetteKid 06-21-2003 11:11 PM

Re: Starting problem.. 1989 C4 (SunCr)
 
Just a shot in the dark here, but nobody's mentioned the MAT (manifold absolute temperature) sensor on the underside of the plenum. Anybody try changing this? For the $20 or so dollars that this sensor is worth, it may be worth it.

But I will admit it's just a guess...

jimmyd 06-22-2003 12:47 AM

Re: Starting problem.. 1989 C4 (SkipI)
 
What is different about these cars 88 & 89 than some of the others ?
It has to be something we are overlooking.
I supect injectors is my problem because they will not hold pressure,
But, they was tested & flowed when the new motor went in.
Maybe we could start a fund and take a car to Gordon.
:confused: :mad :banghead: :confused: :smash:

ONEBAD89 06-22-2003 11:18 AM

Re: Starting problem.. 1989 C4 (SunCr)
 
MAF sensor is about 4 years old, but I think I read where one can disconnect it and try to start vehicle to bypasss it, I'll try that seeing as the car has sat for 2 days now. As for the oil pressure sender it is about 2 years old, but I haven't touched either of the maf relays. Where are they and is there a test for them or just replace them??? Thnaks Again!
FRED

SunCr 06-22-2003 11:56 AM

Re: Starting problem.. 1989 C4 (ONEBAD89)
 
MAF Relays are behind the battery and are relatively inexpensive. The orange wire is the common power from the ECM to the fuel pump relay, oil pressure sender, MAF and MAF burnoff relays. You might try cleaning the MAF sensor wire with electrical cleaner, especially if you've removed the screens and/or have a K & N filter (I've seen a couple of posts with owners reporting that filter oil wrecked havoc on the wire) - though be careful, you don't want to break something that may be ok; so first, you might try observing the wire at shutdown. Should glow if it's reacting to the burnoff signal. Air temp sensor under the plenum is easiest to troubleshoot with a scanner. Like the coolant sensor, cold reading should be about the same as the outside air temp. Otherwise, 3400 ohms if it's 70 degrees.

TheCorvetteKid 06-22-2003 12:20 PM

Re: Starting problem.. 1989 C4 (jimmyd)
 

What is different about these cars 88 & 89 than some of the others ?
It has to be something we are overlooking.
The biggest difference is the lack of the 9th (cold start) injector, and that the '89 was the last year for the MAF sensor - '90 switched to a MAP sensor.



I supect injectors is my problem because they will not hold pressure,
But, they was tested & flowed when the new motor went in.
If you know that your injectors won't hold pressure, then you've found your problem. But from the sounds of things, the rest of us have tested our injectors/fuel system and are finding good steady pressure.


Maybe we could start a fund and take a car to Gordon.
That's a great idea! :lol:

When you add up all the money that we've ALL spent on new sensors, relays, ECMs, switches, injectors, etc... just to find out that it didn't make a difference, it would be cheaper to have a hard-starting '88 or '89 flown in from OVERSEAS to have Gordon take a look at it. :lol:

ONEBAD89 06-22-2003 12:51 PM

Re: Starting problem.. 1989 C4 (SunCr)
 
Thanks Again for the info, btw, I hace removed my screens and I am using a K&N air filter, but just started the car and ran it, shut it down 3 times and no glowing of the wires :confused: Does this mean a problem with the relays?? Are they both refered to as maf relays, so when I'm at the parts store I don't sound like a complete idiot. Thank You!

FRED

O'Shark 06-22-2003 05:39 PM

Re: Starting problem.. 1989 C4 (jfb)
 

You spent money to replace (new plugs, wires, fuel pump relay, dist. cap, rotor), without knowing if they needed replacing, but you are too cheap to buy a fuel pressure gauge to tell you if you have a leaky fuel injector? You aren't thinking clearly. A common cause of hard starting is a leaky fuel injector which can be found by putting a fuel pressure gauge on the shrader valve on the fuel rail, turn the ignition on for several seconds to pressurize the rail, turn off the ignition and see how long it takes to lose 1 psi. GM says it must take more than 30 minutes or you have a leaking injector.
In my case, you touch the key and it starts.....NOW. However, when I connect my FP gauge, it'll leak down to nothing in 15 minutes. I'm thinking that the fuel pump can let it leak down too.

C10 JDR 06-22-2003 05:46 PM

Re: Starting problem.. 1989 C4 (KF9WM's 87 coupe)
 
I think 88 and 89 have different injectors - Multec brand, and this style of injector MUST NOT be cleaned with injector cleaner or anything else, because it rots the insulation on the injector solenoid (or something).

Just a thought.

ONEBAD89 06-22-2003 09:26 PM

Re: Starting problem.. 1989 C4 (SunCr)
 
One additional question, When I removed/replaced my motor I eliminated the egr and all the smog equipment and I just taped up all of the wire plug ends with electrical tape and placed where they would be out of the way under the hood. Could this cause any of the problems I'm having with the start ups??? Thanks!

89convt 06-22-2003 09:31 PM

Re: Starting problem.. 1989 C4 (ONEBAD89)
 
check to see if the injectors are getting pulsed when in a slow start condition

6spd 06-22-2003 11:41 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
i have a problem like this on my 91 changed everything except it only does this in closed loop it starts up when cold takes 5 sec but when it heats up the idle surges any thoughts on this

TheCorvetteKid 06-23-2003 07:30 AM

Re: Starting problem.. 1989 C4 (6spd)
 
This may be another shot-in-the-dark, but I remember reading that there is an upgraded MemCal for the '88-'89 cars. Is this true? If so, maybe that's our problem. It would certainly explain why we are all running around changing sensors, relays, ECMs, etc... and not solving our hard start issue.

Again, just a shot-in-the-dark.

SunCr 06-23-2003 12:02 PM

Re: Starting problem.. 1989 C4 (ONEBAD89)
 
Burnoff cycle occurs only after car has gone closed loop, then approximately 4 seconds after shutdown for 1 second, so make sure you've run it long enough for this to happen or verify loop status with a scanner. Modified engines with low temp thermostats may not go closed loop at idle. MAF could be bad if it isn't responding to the Burnoff signal; but most problems are in the circuitry, Orange (power) or Black (ground to the ECM driver) wires; high resistance in the Relays; or the ECM. Relays are the same: One is for Power; the other for the Burnoff. The Code 36 chart explains the Burnoff circuit, but without the Code, it's probably of little use in troubleshooting. I don't know of any Memcal changes for the '89 (supposedly, a Bulletin was issued in late '89 about an updated Memcal, but it was applicable to prior years). ECMs were updated due to high circuit board failure rate and when that happened, driveability problems were pretty obvious. Most were replaced under warranty and for those who have never pulled it, you might find that when you do, it's allready been replaced.

ONEBAD89 06-23-2003 11:41 PM

Re: Starting problem.. 1989 C4 (SunCr)
 
Thanks for the info, I'll try it out tomorrow. Now that the temperatures here are finally up and above 80 it shouldn't take long for the car to get to closed loop........ Thanks Again........
FRED

SkipI 06-24-2003 04:11 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Okay... here is the latest. I took my car to a local dealer. They have a special corvette shop and a corvette master mechanic. The guy is the gig because he'll talk to you and help you out. Well, he came out to my car and I cranked it up, and yep, it took 2-3 seconds of cranking. He replied, that must be an 88-89. Yep, I replied. He looked under the hood at the injectors and told me that I had the good kind and that the lenght of cranking is right on for these years of vette. He started the car up 7-8 times and told me that the ECM waits for a reference signal from the distributor and sometimes it takes a little more cranking than others to obtain the signal. He also said that there is nothing to replace to fix this. I can attest to this because almost everything involved is NEW!! :lol: So, anyways, after shooting the breeze about a few other items on the car, he told me to hit the road. He did say that there are another model of injectors that were prone to leaking by and end up flooding the engine.... then you end up with a long cranking sequence to get the engine going. I am not sure what he looked at, but he could quickly tell by looking at them if they were that kind or not. Oh well.....

Skip

csc67 06-24-2003 04:33 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Skip,

This guy starts your car a couple of times and chats you up for a couple of minutes and the issue is gone

What happened to "The engine takes anywhere from 5-8 seconds to start when cranking" ??

Did you ever get a SES code ??

Did your extended cranking only happen under certain circumstances that were not present when this guy looked at your car ??

I'm confused.....

Thanks


Okay... here is the latest. I took my car to a local dealer. They have a special corvette shop and a corvette master mechanic. The guy is the gig because he'll talk to you and help you out. Well, he came out to my car and I cranked it up, and yep, it took 2-3 seconds of cranking. He replied, that must be an 88-89. Yep, I replied. He looked under the hood at the injectors and told me that I had the good kind and that the lenght of cranking is right on for these years of vette. He started the car up 7-8 times and told me that the ECM waits for a reference signal from the distributor and sometimes it takes a little more cranking than others to obtain the signal. He also said that there is nothing to replace to fix this. I can attest to this because almost everything involved is NEW!! :lol: So, anyways, after shooting the breeze about a few other items on the car, he told me to hit the road. He did say that there are another model of injectors that were prone to leaking by and end up flooding the engine.... then you end up with a long cranking sequence to get the engine going. I am not sure what he looked at, but he could quickly tell by looking at them if they were that kind or not. Oh well.....

Skip

SkipI 06-24-2003 05:47 PM

Re: Starting problem.. 1989 C4 (csc67)
 

Skip,

This guy starts your car a couple of times and chats you up for a couple of minutes and the issue is gone

What happened to "The engine takes anywhere from 5-8 seconds to start when cranking" ??

Did you ever get a SES code ??

Did your extended cranking only happen under certain circumstances that were not present when this guy looked at your car ??

I'm confused.....
I have never received a SES light. When the mechanic started the car, it cranked as long as it always has. It did crank longer with the old starter, but it starts faster with the new one. There is a considerable difference from the old starter to the new one... the new one really cranks with a vengance where the old one was a lot slower. I think maybe my time estimation of 5-8 seconds was too long. I have been comparing the car with our two other vehicles that pretty much start as soon as the key is turned. The engine starts anywhere from immediately to 2 seconds. I was concerned about the inconsistancy in starting, and if it was a sign of future problems. Troubleshooting pretty much eliminated possible causes... I would like to see the engine fire immediatly every time... but after reading all the posts on this thread, I get the feeling that I am chasing an elusive dream.

VetBoy89 06-24-2003 05:53 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
This is the email reply that I received from Rich at CruzinPerformance.com when I inquired about getting my injectors cleaned from my ‘89, this is another reason anybody that needs injectors to be cleaned should send them to him, not only does he do excellent work but he is an honest guy, as you can see from his response below. :thumbs:


If your injectors are the originals (grey with a silver band) that the car came with from the factory, they are Multecs and have the highest failure rate of any injector ever installed on the L98 engines. It really is a waste of time and money to service them.
They have a faulty design and the solenoid windings short out. There is no repair for this and the only solution is to replace the injectors. Cleaning them will not help.
You can test them to see what condition they are in right now by using an ohm meter and test the resistance of the windings in each injector. They should register about 14 to 16 ohms. If any are below 12 ohms, they are beginning to short out and are in need of replacing.

I get inquiries about these injectors every day and I know that this isn't what you wanted to hear but it simply is a fact that it isn't whether they will eventually fail, it's just a matter of when.
:thumbs:

SkipI 06-24-2003 06:14 PM

Re: Starting problem.. 1989 C4 (VetBoy89)
 
Also, the mechanic I talked to today cautioned about having the injectors cleaned professionally because the injectors are self-cleaning and the cleaning solutions can damage them. This is something I also read in this forum also.

Skip

Tourney3p0 06-24-2003 06:26 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Thanks for keeping us updated.. I've been following the thread.

What I don't understand is how he says there's no way to fix it. There has to be SOMETHING that is different.. by your description it sounds like it'd be the ECM or distributor. The ECM isn't proprietary to the 88 and 89, and neither is the distributor. What else could it be that's different?

If you don't want to talk to him again and don't mind, could you give us the place's number? Hopefully someone (myself included) could get some more information out of him.

SkipI 06-24-2003 06:52 PM

Re: Starting problem.. 1989 C4 (Tourney3p0)
 
Okay, I'll try my best to remember how he explained it... it is something about the pick-up in the distributor. Apparently in the past, the magnetic pick-up on the distributor was so close to the rotating poles that they were sometimes coming in contact, so GM widened the gap. This means that the poles must move faster to send a signal. Also, it sorta sounded like there was a reference pulse, and if the ECM missed the reference pulse, it would have to wait for it to come around again. I am not sure if I explained the last part right... but he specifically stated that this was a 88-89 issue.

C10 JDR 06-24-2003 07:56 PM

Re: Starting problem.. 1989 C4 (VetBoy89)
 
Multecs are not a faulty design - they are self cleaning - but if you try to clean them or use fuel additives you will have problems.

MtlSphere 06-24-2003 09:00 PM

Re: Starting problem.. 1989 C4 (britvette)
 
This thread begs the question...how to identify your injectors?

Remember...junior member...handles criticism well...

I'm still new to the TPI. My injectors are black with a yellow stripe or band if I remember correctly. Can't say that I've spent a lot of time just looking at the injectors. But I would like to know more about them. :cool:

ONEBAD89 06-24-2003 11:03 PM

Re: Starting problem.. 1989 C4 (MtlSphere)
 
Checked out the condition with the MAF relay after the car went to closed loop and yes it did glow after I shut the car down, which I suppose means that the MAF relay works and it is still something else. As I mentioned earlier when I replaced the ecm it worked/started perfectly whether hot or cold about 1 half a crank and it would start, morning or night which it also did prior to engine removal/replacement. I also replaced my fuel injectors with new Bosch injectors from TPIS. Thanks again for the help I'll keep trying...... :banghead: :banghead:

SkipI 06-25-2003 03:53 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
How about a scientific approach? I am going to time how long it takes to start my car for the next 2-3 days. Then I'll post my results here. I'll time from key turn to engine firing. I'll also note whether the engine was cold or hot. Could some of you do this also? We could compare notes and see what is going on out there.

Skip

ONEBAD89 06-25-2003 08:45 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
Sounds like a plan to me...... I can tell you this much, now that it is like 90 + during the day and only down to about 65 at night it hasn't had many problems starting, because it is warm out. Main problem during early spring and late fall when the temps get down in the 40's at night. Right now, usually 3 sec. crank in the morning on the first try, then the next one/two is only about a second, she'll catch and run. In the afternoon on a hot day, usually about 2 seconds first time and instantly if a second is needed. Meaning that the problem has something to do directly with temperature, at least for me. Good Luck guys, I'll keep you posted.
Thanks
FRED :confused:

jfb 06-25-2003 09:39 PM

Re: Starting problem.. 1989 C4 (SkipI)
 
I just talked to my vette mechanic who works for a Chevy dealer and only works on vettes and is sent to the vette school every year. I asked him if 88 and 89 vettes take long cranks to start. He said , "No, they should start right up". If your injectors have a green band , then they have been replaced from the original black band injectors that have a tendancy to leak, causing hard starts. GM replaced the original injectors under warranty. My mechanic replaced my 87's injectors early on while it was still under warranty with the green band ones, they are Lucus, the black bands are Bosch. He said if when it does start, there is a lot of dark smoke in the exhaust, you probably have leaky injectors, otherwise your long cranks are due to being too lean to start immediately.

ONEBAD89 06-26-2003 09:49 AM

Re: Starting problem.. 1989 C4 (jfb)
 
I'll have to get back to this problem later...... Just blew up the tranny again!!! :mad :mad :mad Have to get it fixed before I can drive, and of course had to happen 3/4 of the way to work on the busiest hwy, at the busiest time of the day!!! :mad :mad :mad

SunCr 06-26-2003 11:22 AM

Re: Starting problem.. 1989 C4 (SkipI)
 
[QUOTE]How about a scientific approach? I am going to time how long it takes to start my car for the next 2-3 days. Then I'll post my results here. I'll time from key turn to engine firing. I'll also note whether the engine was cold or hot. Could some of you do this also? We could compare notes and see what is going on out there.

Skip[/QUOTE
Too quick to time; hit start & it fires - cold, hot or inbetween.

ski_dwn_it 06-26-2003 01:28 PM

Re: Starting problem.. 1989 C4 (SunCr)
 
Guys,

I did not read the entire post, but most of it. Let me give a little insight from the tabels that are used for fueling on startup.

There are several that are used to assist in the startup. They are illustrated here with their respective values:

http://temp.corvetteforum.net/c4/ski...artup_fuel.jpg

1. Crank Fuel Pulse vs Coolant Temperature. This on supplys the bulk of the PW.

2. Crank pulse width multiplier vs TPS

3. Crank Pulse width multiplier vs crank ref pulse 1-16

4. Crank Pulse width multiplier vs crank ref pulse <17

Ok now that we can see the tables and their values we can further discuss how they work and why some of you might be having problems. Especially after modification to the engine are made. This is assuming that you don't have faulty(leaky injectors) etc.

OK when you hit the ignition the first think the ECM does is determine the coolant temperature for the coolant sensor on the front of the manifold. It then goes to table 1 oulined above (I am not going to write out the names each time, but rather just the respective numbers above). As you see the colder the coolant the more PW that is needed and the more fuel delivered. It then takes that pulse width and goes to the table #2 (TPS) and multiplies the pulse width times that value.....here you can see most all the values are 1.0 so TPS doesn't even effect the fuel delivery, but it effects something else I will soon get to. The ECM then references the tables 3 and 4 which are sent my the distributer as reference pulses. As you crank longer and longer the multiplier gets larger and larger, but becuase its less than 1 its actually cutting back on fuel. Play with the math you will see what I mean. The reason is, as you keep cranking if it did not cut back on the fuel you would drown the engine if it did not start.

Ok now that you have a pretty decent idea how the tables work. Let me explain what some of your poblems might be...more specifically if you altered something in the intake stream, ie MAF screens anything that altered the intake air stream, including the filter etc. People that changed to larger injectors or higher Fuel pressures forget it. These table are all out to lunch and hence your tough starting.

Now let me explain further that its very simple to find out where you are at. Now again it should be expressed that this is butt/u/me-ing that you have do not have leaky injectors, in that case you loose control obviously of what is going on and hence flood the engine, even with the key in the off position.

OK. To see what you are at. If your foot on the gas peddle at startup and the car starts quicker, it not that your adding more fuel, as seen in the table TPS, it your adding more AIR! So that means that you have to compensate the added fuel from the pressure increase or the larger injectors or both. So what I do is decrease the PW adjustment in the coolant temp until you get a crisp clean start. How do I know all this. I have had two engines that would not start after modding and did exactly what you guys all describe. And this is how I cured the problem. Now I can reach through the window and hit the key and within 3 cranks its started.

Remember that the ECM is ignorant, and only as smart as you teach it to be. In a startup situation its only has these tables to go off of. No O2 sensor readings, nothing. So they have to be accurate to have precise starting.

You may say that well my inj are stock and so is the car, but over time my starting has deteriorated. I check the inj and they don't appear to be leaking and hold pressure for 30 min. True and I have a few things that might also cause problems just in the fuel system. 1. Pump might be getting weak at first. 2 FP outputs are VERY much influenced by voltage 3. return line to the tank has a direct and influencial bearing on line pressure/fuel delivery 4. Octane rating and quality of used fuels, definately will influence starting characteristics

Pretty neat stuff when you see what is going on huh?

It should also be said that I'm sure the MAF meter has some bearing on the startup, but I've never see any actual evidence of that. Not to say there isn't. But some items do lead me to believe there is a link. But the main tables that influence the startups are the ones I outlined here.

I need to get Mojo to make some stickies, so these posts do not get lost.

Hope to hear some replies to this.

:cheers:


[Modified by ski_dwn_it, 10:52 AM 6/27/2003]

ski_dwn_it 06-26-2003 06:50 PM

Re: Starting problem.. 1989 C4 (ski_dwn_it)
 
Jeeeesh, glad I typed all that :nonod: :confused:


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