C5kid

First off I am A&A SIC kit running 5-6# and had it tuned @ ECS, i have DRM LT headers on but still have the main CATS on the car and lately if i goose the throttle jsut right the car w/ like cut out around 4k adn then pick up, i guess teh key is that I am not totally into the gas i am only slowly leaning into it adn get to WOT at 5k

Could the CATS be blocked or is something w/ the tuning?? It has always done it (motor had 40k when SC was installed)

Also now when I am just cruising around if am goin like 35-40 and just barley touching the throttle I get some bucking and stuff liek it can't decide to give it more fuel or less fuel. I pulled the plugs all of them look great even for running 10.2-1 A/F @ WOT

Hopefully someone will ahve some input... Chris or Doug @ ECS if you get to read this let me know what you think, i am goin to come back out this spring once the pistons and rods are swapped out...

THANX Dustin

DOUG @ ECS

Duston,
Sounds like you need to log your car to start.
If your a/f is really 10.2 than something is off because there is no reason a tune should change for any reason short of reprograming.
Start with that and let me know.

dads01dream

What's a good program to "log" with??

mdhmi

EFILive.

Mark

C5kid

Chris set the A/F @ 10.2 just to be safe since i m running to stock bottom end.

here is a pic of my dyno pulls that i made at your place....


i cut of the bottome but that is the RPM across the bottom of the pic


what do you think about the cats? should i ditch them before i get another tune? cause i have been reading about them getting clogged up and running the 10.2 a/f once and awhile doesn't help

dads01dream

Whoa! And I thought I was tuned safely at 11.6!!! I think you're single-handedly keeping OPEC in business.

BlackMagicC5

I'm having the same problem. When I hold it at slight throttle for cruise, no matter what rpm, I get some bucking. I checked my plugs and they looked fine as well. I also started out at 10.0-1 A/F and ran it that way for a little while. I thought maybe the rich tune contributed to the cats clogging up. Does that make sense? I am thinking about ditching the cats to see if thats the problem.

mdhmi

Gut the cats.

Mark

BlackMagicC5

Good idea, how do I do that?

mdhmi

With mine we took a large metal bar and a hammer. Took about an hour.. Basically you put the large metal bar inside the cat (obviously the cat was removed from the car first) and bang away until the cat goes by by.

Mark

SleepieAce

Mine has no cats and has the same problem. A slight hesitation at 4K or so when part throttle accelerating up to redline. I'm trying a couple things. Bigger injectors (God knows why ATI supplies 38# ) and having it retuned. It's still got off the shelf tuning on it which is most of the problem I think, at least for me.

Hool97

with logging the fuel trims. You may need to adjust the VE tables. During throttle transients this controls the AFR. Then the system either switches to open loop or adjusts to the 02 sensor.

mfrnka

I'm getting the exact same issue. I'm running MAF-less with VE tuning. Runs great a full throttle, but part throttle if I ride up the RPMs my AFR will take a dive into the low 10s.

Anyone think this is a BOV issue? I'm still running the plastic piece of junk. Under high rpm, it could be cracking open and bleeding off air?

Hool97

One thing can be done if you are already MAFless is plum in a boost referrence line and connect it to a 2 or 3bar gm MAP. Send the output to an analogue input on for example an LM-1 wide band and monitor. I use this and it reads on my laptop 0-5 volts = -14.7 to 14.7 psi with a 2bar MAP. This lets me know what boost i have at a given rpm and AFR. Nice little device (i do use an rpm module with the LM-1).

This will let you know very quickly if BOV or boost loss is an issue.

dads01dream

So, what's considered a good tuning software to make adjustments to VE tables? If a car is already tuned using LS1edit, can you make revisions to a tune using something like HP Tuners???

BlackMagicC5

I don't know if this helps any, but my problem never happens in the first minute or two of driving when the car is cold. Thats when its the smoothest. After that time, at slight throttle cruise, I get some bucking. I also get it on deceleration, and sometimes right before I step on the clutch when coming to a stop.

dads01dream

Hey blown......

You had my attention right up to the point where you mentioned "right before I step on the clutch". My car's an A4. Maybe our issues are tuning in nature and not my t/c after all??

The plot thickens......

NCxtrooper

You need to find a good tuner!

myblackC5

if you gut the cats it will run rich again. it will be in the open loop. running rich will ruin the cats, it's like pouring gas on a bar-b-que. get new cats.......

NCxtrooper

Tuning will that care of that, you don't need cats. Gut them tune them out, get it tuned for part throttle fueling and you are good to go, not to mention adding 20 or so hp.