socalman

Welcome to the New and Improved C4 DIY Sticky.
Thanks to all the great members here for sharing their experiences. This would be an empty thread without all of you.

If you've done any mod, repair etc. with pics, post just the link here.



*** SECTION I ***: MISC C4 INFORMATION 1984-1996

IMPORTANT FIRST THING TO DO WHEN YOU BUY YOUR C4 [/B].....

EMERGENCY HOOD RELEASE

http://forums.corvetteforum.com/c4-g...with-pics.html

HOOD WON'T RELEASE

http://forums.corvetteforum.com/c4-t...-not-open.html


OTHER ITEMS LISTED IN THIS THREAD

1.) HOW TO PULL CODES FOR YOUR C4- Post #18

2.) TROUBLE CODES LISTED 1984-1996 -Post #35

3.) All RPO CODES BY YEAR 1984-1996- Post #31

4.) FRAME DRAWINGS AND PICTURES-Post #37

5.) PAINT COLORS LISTED BY YEAR 1984-1996- Post #39

6.) BUYERS GUIDE AND PRE-PURCHASE CHECKLIST (What should I look for in a C4?)

http://www.corvettephotographs.com/c...repurchase.htm


*** SECTION II***- MEMBER HOW-TO PICTORIALS

LT1/LT4 SPECIFIC REPAIRS/REPLACEMENTS

LT1/4 Opti Spark 'Video' (How it works..How to diagnose) POST #48

LT1 Optispark/Waterpump Install
http://forums.corvetteforum.com/c4-t...-pictures.html

LT1 Fuel Injectors (Bosch III Install)
http://forums.corvetteforum.com/c4-t...post1570923182

LT1 Brake Booster Replacement
http://forums.corvetteforum.com/c4-g...with-pics.html

LT1/4 How to change Spark Plug Wires
http://forums.corvetteforum.com/c4-t...lug-wires.html

LT1 Fuel Pump
http://forums.corvetteforum.com/c4-t...s-of-pics.html

L98 SPECIFIC REPAIRS/REPLACEMENT

How to Adjust TPS and Idle
http://forums.corvetteforum.com/c4-t...dle-speed.html

4+3 O/d filter
http://forums.corvetteforum.com/1571645223-post6.html

TPI Sensor Locations and resistance values
http://www.corvettebuyers.com/c4vett...nformation.htm

90/91 Tacho Problems (Read Both!)
http://forums.corvetteforum.com/1574563401-post2.html

Park brake adjust 84 - 87
http://forums.corvetteforum.com/1560187929-post1.html

4+3 Trans Operating differences by year
http://www.5speeds.com/43table.htm

GENERAL REPAIR/REPLACEMENT (L98/LT1/LT4)

Battery Replacement
http://www.corvettemagazine.com/2001...ttery/bat1.asp

Headlight Motor Bushing Replacement
http://www.corvettefever.com/howto/33098/index.html

Park brake adjust 88+
http://forums.corvetteforum.com/1574610903-post5.html

Replace tail lights/bulbs
http://forums.corvetteforum.com/1568414438-post5.html

Headlight bushing replace ( late 2 wire )
http://home.comcast.net/~zrjuan/headlight.html

C4 Engine wiring Diagrams (inc fans / lights /charging )
http://www.franken-us-buddys.de/inde...-%20Wiring.pdf

Fuel gauge sender repair
http://forums.corvetteforum.com/c4-t...h-article.html

Weatherstrip
http://forums.corvetteforum.com/c4-g...therstrip.html

VATS Bypass/Removal/Troubleshoot
http://www.vatssucks.com/

INTERIOR

Effective, permanent fix to sagging door trim panels, using wire ties
http://forums.corvetteforum.com/c4-g...wire-ties.html

Visor Replacment
http://forums.corvetteforum.com/c4-t...tallation.html

84 -86E Window Regulator upgrade (or fix 86L+)
http://webpages.charter.net/khasting...windowreg.html

85-89 Instrument Cluster Bulb Replacement
http://forums.corvetteforum.com/c4-g...ent-guide.html

CAR AUDIO REPAIR/UPGRADE/SWAPS

1984-1989 Front Speaker Replacement
http://www.carstereohelp.com/stereor...etteFspk89.htm

1995 Antenna Fix w/ Pics (lots of pics)
http://forums.corvetteforum.com/c4-t...s-of-pics.html

'96 Full Stereo Re-do, Part I (no 56k)
http://forums.corvetteforum.com/c4-g...-i-no-56k.html

Broken Power Antenna Ribbon Tip
http://forums.corvetteforum.com/c4-t...ibbon-tip.html

ENGINE BUILDS/SWAPS

PLRX LT4 Build Up
http://forums.corvetteforum.com/c4-t...-plrx-lt4.html

LT1 to LS2 Swap
http://forums.corvetteforum.com/c4-t...ction-pix.html

MODS/UPGRADES

Lowering the C4
http://webpages.charter.net/khasting.../lowering.html
...and another twist to lowering
http://forums.corvetteforum.com/c4-g...-i-did-it.html

Hardtop on an 86-88 (Retrofit)
http://forums.corvetteforum.com/c4-t...post1577847733


C5 Brake Upgrade
http://forums.corvetteforum.com/c4-t...done-pics.html

LT1/4- What NOT to waste your $ on
http://web.archive.org/web/200801201.../increase.html

LT1 More HP
http://web.archive.org/web/200801201...rformance.html

Upgrading Auto Trans- Install a 4L80E
http://www.joby.se/corvette/mods/2004-12-26_4l80/

Mod to use D36 C Beam with D44 swap
http://www.joby.se/corvette/mods/2001-0X11_diff/

Installing Coilovers LT1/LT4
http://forums.corvetteforum.com/c4-t...r-summary.html

DeWitt Aluminum Radiator Install
http://forums.corvetteforum.com/c4-t...tallation.html

HID Install:

Fog Lights & Markers
http://forums.corvetteforum.com/c4-t...installed.html
Tail Lights
http://forums.corvetteforum.com/c4-g...ion-picts.html

L98 Trans Swap- 4+3 to T56
http://members.cisdi.com/~anesthes/f-car-t5/

Lowering your C4 (Front and Rear)
http://webpages.charter.net/khasting.../lowering.html

Light Grill Mod
http://forums.corvetteforum.com/c4-g...you-think.html

1984 SPECIFIC

Parking Brake Adjust 84-87
http://forums.corvetteforum.com/1560187929-post1.html

4+3 Trans Operating differences by year
http://www.5speeds.com/43table.htm

4+3 O/d filter
http://forums.corvetteforum.com/1571645223-post6.html

Oil Pan Gasket Replacement
http://forums.corvetteforum.com/c4-g...t-placing.html

j-vette

Good thread idea

SQUIRMIN VERMIN 84

This is a GREAT idea!!!!!

ch@0s

This is too cool I'm going to spend some time going over this thread this weekend.. Great idea

Wow! Pete

Kubs

Great idea! Thanks guys!

kenv

This is way - Thanks-

uptown193

Wow......Great work on this thread. Very Very useful. This thread should be left on top at all times.

I respectfully bow my head to you.

pewter99

Enjoy folks...you now have your very own Tech sticky

dogfish246

Nice work! It use to be difficult to find the good info, but not now!

ch@0s

Thanks to you and Socalman

rusvette

front brske pad replaced

COPO

LS Swaps???

socalman

You got it. Thanks to you, PLRX, BLACKHARLEYMAN and FC SOLDIER, we now have a cool new subcatagory-

Check it out y'all!

ENGINE REBUILD/SWAPS now in the opening post

BrianCunningham

but isn't there on in the tech section???

http://forums.corvetteforum.com/c4-t...tions-too.html

socalman

This has much, much more.

mbowers13

I'd like to request that the write-up from this member's (StealthLT4) Audio upgrade be listed as well.

Part 1:
http://forums.corvetteforum.com/c4-g...-no-56k-2.html

Part 2:
http://forums.corvetteforum.com/c4-g...ii-no-56k.html

Although both the one listed in the beginning and Stealth's are 96's, they differ in front speaker solutions.

socalman

Done deal

socalman

ALDL 201 (OBD I)

1981 Corvette (L81) models have a very simple computerised ignition timing system. There is very little diagnostic information available with these cars. The GM shop manual is recommended for this vehicle. The ALDL connector is under the centre console ash tray.

1982 Corvette (L83 Crossfire) models had a more detailed ECM, much like later vehicles. The location of the ALDL connector is under the centre console ash tray. The diagnosis is more simplified, but similar to later vehicles.

From 1984 until the end of the 1993 model year a 12 pin ALDL was used. After that, a 16 pin ALDL connector was used. The 1994 and 1995 model year still used the OBD-I system even though they have 16 pin connectors. The 16 pin connector in the 1996 C4 is used for the much more complex OBD-II system and a scan tool is required to discover the OBD-II system's secrets.

For the '84- end of '93, 12 pins:


Pin "B" is the diagnostic enable pin and pin "A" is ground. Grounding pin "B" to enable the diagnostic readout of the ECM/PCM.

To recover the codes, short pins "A" and "B" together using a small section of electrical wire or paper clip.

With the ignition turned OFF, short pins "A" and "B" on the ALDL.

Turn IGN ON (but not to RUN).

The "Check Engine" light (early C4s) or "SYS" light (later C4s) will flash a Code 12 (a single flash followed by two flashes) and will repeat three times (Flash (pause) Flash Flash (long pause), Flash (pause) Flash Flash (long pause), Flash (pause) Flash Flash (long pause).

Code 12 is a delimiter or marker code to show where the error code string begins and ends.

After the three Code 12 flashes, you will either get an error code (or codes) or you will get another string of Code 12 flashes if there are no trouble codes stored.

All codes are repeated three times with a long pause between each code group (36 or Flash Flash Flash pause followed by six flashes, repeated three times, folowed by a long pause with any additional codes stored then flashed).

The "Check Engine/System" light on with engine running means the condition(s) are currently present. If the light is not on during RUN operation, the limits were exceeded at some point in time and the event was recorded in memory, but the reading has since returned to the normal operating range.

Remember to remove the shorting device from the connector after you have read the codes.

Clearing the Codes

To clear the codes from memory, remove the negative battery cable for a minimum of 10 seconds.

Disconnecting the battery will clear all stored codes and and any stored memory (radio button presets, clock, trip odometer, average gas mileage memory, power seats). Your ECM/PCM computer will also have to relearn timing/mixture/exhaust emissions.

Make absolutely certain the ignition key is turned OFF. If you connect the battery with the ignition switch ON, you can destroy the ECM/PCM module.

For 1994 and later models, you will need to recover the codes using a special procedure involving the speedometer and the odometer as explained in the service manual or use a special diagnostic device known as a scan tool.

For the '94 - '95, 16 pins (but still OBD I):



Beginning in 1994, you short pin "12" to pin "4" and once again turn the ignition switch to "On" without starting the engine.

The speedometer will display any codes using the same protocol as the 1990-1993 model but there are some changes in the designation for the modules plus additional modules are added:

Module "1" is still the CCM module.

Module "4" is now called the PCM module (Powertrain Control Module) because automatic transmission computer control was added to Engine Control Module in 1994.

Module 7 (on the 1996 model only) is the RTD module. (This is the Real Time Dampening module which replaced the Selective Ride Control module in 1996).

Module 9 is the ABS/ASR module number from 1994 through 1996.

Finally, Module "A", the DERM (Dynamic Energy Control Module --- the air bag control module) will be requested to show any codes.

Just like the 1990-1993 display, you read the codes on the speedometer and read the module number on the trip odometer.

Again, you can cause the codes to repeat by turning the ignition off for five seconds and then back on.

Turn the ignition off and remove the short to restore normal operation.

1996 to 2004 Corvette (OBD II):

Turn IGN ON, ENG OFF.
ON DIC, Press RESET button to clear any warning messages.
Press and hold OPTIONS.
While holding OPTIONS, press FUEL four times within 10 sec.

Go into an AUTOMATIC mode to shows all parameters: PCM-TCS-RTD-BCM-IPC-RADIO-HVAC-LDCM-RDCM-SCM-RFA. If there are no problems, you will see "NO MORE CODES" on the ICP display.

The computer displays two kinds of codes, CURRENT and HISTORY, designated "C" or "H". A CURRENT code indicates a malfunction is present in the system whose module is displaying data. A HISTORY code indicates a past problem.

When the screen displays MANUAL DIAGNOSTICS, select the desired module by pressing the OPTIONS button to go forward or the TRIP button to go back. Press GAUGES to go forward or FUEL to go back.

To exit the diagnostic mode at any time, press E/M. If you want to erase or CLEAR codes, press RESET.

socalman

Some new goodies added

Pop Evans

I humbly offer the High Reading Tack post. Seems like there was some interest. Might add it to the other 2 you already have.
You're doing a great job....
Regards Pop

http://forums.corvetteforum.com/c4-g...post1575222722