Known C4 issues
Thread Starter
Racer
Joined: Sep 2017
Posts: 452
Likes: 55
From: Marianna Fl
Known C4 issues
As I am progressing with my 1990 vette I am finding little things that are not working. So far we have bad injectors, cooling fans/relay not working, LCD wont display, daylight sensor isn't working and the door switches for the rear hatch don't work. The dash and weatherstripping also need work from sun exposure.
I am about to order new injectors and know they sell a repair kit for the LCD and the light detector. I have to test to see if the fan motors work at all and will take care of that on my next day off. Are there any other gremlins that are common for a C4 I can try to track down before I get my self stranded away from home?
I am about to order new injectors and know they sell a repair kit for the LCD and the light detector. I have to test to see if the fan motors work at all and will take care of that on my next day off. Are there any other gremlins that are common for a C4 I can try to track down before I get my self stranded away from home?
Le Mans Master
Joined: Dec 2005
Posts: 8,561
Likes: 946
From: Communist Colorado
Fuel pumps & relays
Steering rack gets morning sickness
Antenna usually is broken by now
Bose stereo amp issues
Driver seat bolsters wear
1/2 shaft U Joint
Wheel Bearing Assemblies
Headlight motor gears wear out
power seat lumbar bladders
That said the stuff you mention is pretty common stuff...
Steering rack gets morning sickness
Antenna usually is broken by now
Bose stereo amp issues
Driver seat bolsters wear
1/2 shaft U Joint
Wheel Bearing Assemblies
Headlight motor gears wear out
power seat lumbar bladders
That said the stuff you mention is pretty common stuff...
Last edited by 81c3; Oct 18, 2017 at 04:37 PM.
Racer
Joined: Apr 2017
Posts: 337
Likes: 26
From: San Antonio, TX
I'd add that pesky problem where the hood release quits working, might want to see about installing the emergency release for that early, it's a cheap repair if I recall correctly
If you can get spare abs sensors I'd get them, nobody really makes them anymore that I've found
The door panels get wonky, alot of C4's will have their panels start hanging away from the door and leaving a giant gap between window and panel
The visors tend to get floppy eared, my fabric has started disintegrating
There's a couple more that I can't remember, but I think 81c3 got most of them. Most of the problems you're having are pretty common
If you're getting in to change the fans, I'd recommend checking out the radiator. Often times it can get clogged with any grass, dirt or debris it sucks up off the ground, and that'll kill your temps.
How long have you had her? Any maintenance records for her to reference?
If you can get spare abs sensors I'd get them, nobody really makes them anymore that I've found
The door panels get wonky, alot of C4's will have their panels start hanging away from the door and leaving a giant gap between window and panel
The visors tend to get floppy eared, my fabric has started disintegrating
There's a couple more that I can't remember, but I think 81c3 got most of them. Most of the problems you're having are pretty common
If you're getting in to change the fans, I'd recommend checking out the radiator. Often times it can get clogged with any grass, dirt or debris it sucks up off the ground, and that'll kill your temps.
How long have you had her? Any maintenance records for her to reference?
Last edited by KenMathisHD; Oct 18, 2017 at 06:57 PM.
Team Owner
Joined: Dec 2007
Posts: 20,974
Likes: 261
U-joints
bushings
hubs
steering wheel wobble
tape deck / cd player issues
head gaskets
depending on year fuel injectors
shocks
weatherstripping
vats
heater core
abs on some years
automatic 3-4 clutch pack
windows go up slower on earlier cars
dash isssues
bushings
hubs
steering wheel wobble
tape deck / cd player issues
head gaskets
depending on year fuel injectors
shocks
weatherstripping
vats
heater core
abs on some years
automatic 3-4 clutch pack
windows go up slower on earlier cars
dash isssues
Thread Starter
Racer
Joined: Sep 2017
Posts: 452
Likes: 55
From: Marianna Fl
Well the all the parts of the fuel system have been replaced or are on order so fixes that issue. I will keep an eye open for the rest of the mentioned issues. Thankfully I wont suffer the same issue a friend of mine did with the 3-4 clutches, kinda hard in a ZF. I will look into the hood release pretty soon.
Team Owner
Joined: Dec 2007
Posts: 20,974
Likes: 261
Well the all the parts of the fuel system have been replaced or are on order so fixes that issue. I will keep an eye open for the rest of the mentioned issues. Thankfully I wont suffer the same issue a friend of mine did with the 3-4 clutches, kinda hard in a ZF. I will look into the hood release pretty soon.
These were not built to last. They were built with mostly off the shelf gm parts though so that helps. Except the clutch for the zf is an issue for some people.
Thread Starter
Racer
Joined: Sep 2017
Posts: 452
Likes: 55
From: Marianna Fl
The clutch dose make a horrible racket when engaged but not under load. I suspect it is either the springs in the friction plate or the throw out bearing. With the clutch pedal depressed or while driving there is no noise and there is no noticable slop in the drive line. On the note of a clutch is it the same pull type as what you get on an LT1 or is it the conventional push type?
Pro
Joined: Jun 2008
Posts: 674
Likes: 235
From: Louisville Kentucky
2023 C4 of the Year Finalist - Unmodified
2022 C3 of the Year Finalist - Unmodified
2021 C4 of the Year - Unmodified Finalist
2018 C4 of Year Finalist
2015 C4 of the Year Finalist
And don't forget the "Air Bag" light problem on the 1990 models.
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Thread Starter
Racer
Joined: Sep 2017
Posts: 452
Likes: 55
From: Marianna Fl
Pro
Joined: Jun 2008
Posts: 674
Likes: 235
From: Louisville Kentucky
2023 C4 of the Year Finalist - Unmodified
2022 C3 of the Year Finalist - Unmodified
2021 C4 of the Year - Unmodified Finalist
2018 C4 of Year Finalist
2015 C4 of the Year Finalist
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,282
From: Hartford WI
As I am progressing with my 1990 vette I am finding little things that are not working. So far we have bad injectors, cooling fans/relay not working, LCD wont display, daylight sensor isn't working and the door switches for the rear hatch don't work. The dash and weatherstripping also need work from sun exposure.
I am about to order new injectors and know they sell a repair kit for the LCD and the light detector. I have to test to see if the fan motors work at all and will take care of that on my next day off. Are there any other gremlins that are common for a C4 I can try to track down before I get my self stranded away from home?
I am about to order new injectors and know they sell a repair kit for the LCD and the light detector. I have to test to see if the fan motors work at all and will take care of that on my next day off. Are there any other gremlins that are common for a C4 I can try to track down before I get my self stranded away from home?
Race Director
Joined: Oct 2011
Posts: 16,086
Likes: 819
From: Dallas Texas
2025 C4 of the Year Finalist - Modified
Considering what 6 speed manual trans were available at the time, they are pretty damn tough. Stronger than a T56 for sure. Costly to fix, yes. But if one had a 700r4/4l60/4l60e failure, you should rebuild it with stronger parts. And that won't be cheap either. So that's why to me, it is better to go ZF. Plus, you can make better exhaust sounds with it.
Thread Starter
Racer
Joined: Sep 2017
Posts: 452
Likes: 55
From: Marianna Fl
Le Mans Master
Joined: Dec 2005
Posts: 8,561
Likes: 946
From: Communist Colorado
Actualy they where replaced with what looks to be the same as what came in the LT1 engines ( Rochester I think?) The repair bill was 1300 just for the injectors back in 2004. So glad I didn't pay for that. I am actually picking up a set of these. I know cheep ebay but for the purpose of getting up and running why not give them a try? I have had surprisingly good luck with ebay parts as of late and if they last me 6 months to a year so I can troubleshoot everything else they where worth the money.
Thread Starter
Racer
Joined: Sep 2017
Posts: 452
Likes: 55
From: Marianna Fl
Thats fine. I have bought these kind of parts with low expectations before and got great results for a fraction of the cost. And with injectors the only "rebuild" you can do is pull the filters, drop it in a sonic cleaner and replace the o-rings. They are designed to never be opened once assembled.
Neither here non there until I get them in anyway, but thanks for all the other things to look at while I get this thing ready for a first distance drive. Quick question, how high on the dash is the trigger point for the coolant fans? When I had the car running before it got pretty warm but the fans never kicked on. I have checked the fans and relays all work, I can even trigger them from the PCM plug.
Neither here non there until I get them in anyway, but thanks for all the other things to look at while I get this thing ready for a first distance drive. Quick question, how high on the dash is the trigger point for the coolant fans? When I had the car running before it got pretty warm but the fans never kicked on. I have checked the fans and relays all work, I can even trigger them from the PCM plug.
Le Mans Master
Joined: Dec 2005
Posts: 8,561
Likes: 946
From: Communist Colorado
Thats fine. I have bought these kind of parts with low expectations before and got great results for a fraction of the cost. And with injectors the only "rebuild" you can do is pull the filters, drop it in a sonic cleaner and replace the o-rings. They are designed to never be opened once assembled.
Neither here non there until I get them in anyway, but thanks for all the other things to look at while I get this thing ready for a first distance drive. Quick question, how high on the dash is the trigger point for the coolant fans? When I had the car running before it got pretty warm but the fans never kicked on. I have checked the fans and relays all work, I can even trigger them from the PCM plug.
Neither here non there until I get them in anyway, but thanks for all the other things to look at while I get this thing ready for a first distance drive. Quick question, how high on the dash is the trigger point for the coolant fans? When I had the car running before it got pretty warm but the fans never kicked on. I have checked the fans and relays all work, I can even trigger them from the PCM plug.
