Check engine light, 1988 Corvette

[Bill S.]

I'm not sure I'm using your system right, but here goes!

I have a very nice '88 Red vette. with the Z52 pack. has 104k, but looks and runs great. No Leaks!
I have done a lot of things to try and get the "check engine light," to say Off. Meaning some days it on and some days it's off. Most of the time it's on.
Things I have done:

1. Cleaned injectors
2. replaced plugs
3. had wires checked. (No miss)
4. Put 1 new oxygen sensor on. They said their was 2, but we only found 1.

I been told to buy a EGR Value Temperature switch. ($60.) @Keens Parts), If bad, That shows a code 32. What is code 32?

Thanks.

Bill S.

[Brian M.]

Re: Check engine light, 1988 Corvette

Check the gas cap.

[Edward J.]

Re: Check engine light, 1988 Corvette

Bill , Code 32 does relate to a EGR system problem, A few things you can check would be the vacuum lines that go to the solenoid sometime they can break,I believe they are plastic. another check is with a vacuum pump to check the operation of the EGR valve its self. if you disconnect the vacuum harness at the solenoid and apply vacuum to the hose that runs to the valve (have the engine running) This will open the valve and cause the engine to stall.This will tell you if the valve is operatiing, if its working its a good think as its a pain to remove. the next step is to test the EGR solenoid .The easy way this works is the solenoid has one wire with constant power and the computer will ground the other side to operate, To test, is to take a common 12v test light and ground the clip and have the engine running and peirce the ground side of the solenoid wire( make sure when you pearce a wire you do in a area hat you can tape the harness afterwards), this will cause the solenoid to open and vacuum will be allowed to flow to the EGR valve and will cause the engine to stall if its working.

PLEASE NOTE THAT THESE TEST ARE ONLY OPERATIONAL TESTS OF COMPONETS.IT DOES NOT TELL YOU IF YOU HAVE A WIRING ISSUE OR COMPUTER DRIVER PROBLEM.

Let me know how you make out, The EGR temp. sensor has been known to be problems but would at least make a atempt to check these first.( They to can be a problem to install as the harness for it is buried and is hard to get to.)

[Bill H.]

Re: Check engine light, 1988 Corvette

Bill, If you own a C4 and want to work on it, you have to have a FSM (Factory Service Manual). It's hard to fix many things without one. Throwing parts at it will be expensive.
If you had the FSM, an explaination and diagnosis chart would be available.
What Ed says is correct on the code 32 and the 32 can be anything in the EGR system. The light going off and coming back on is typical for an EGR problem. You have to find the bad component by doing the checks, again in the diagnosis charts.
I'd do what Ed recommends as a start.http://www.corvettephotographs.com/c4vettes/codes.htm

Luckly, you can pull codes on a C4 by jumping 2 connections on the ADL (Diagnostic Connector). The top paragraphs here describe the procedure for your year: http://www.corvettephotographs.com/c4vettes/codes.htm

Good Luck

[Joe L.]

Re: Check engine light, 1988 Corvette

I'm not sure I'm using your system right, but here goes!

I have a very nice '88 Red vette. with the Z52 pack. has 104k, but looks and runs great. No Leaks!
I have done a lot of things to try and get the "check engine light," to say Off. Meaning some days it on and some days it's off. Most of the time it's on.
Things I have done:

1. Cleaned injectors
2. replaced plugs
3. had wires checked. (No miss)
4. Put 1 new oxygen sensor on. They said their was 2, but we only found 1.

I been told to buy a EGR Value Temperature switch. ($60.) @Keens Parts), If bad, That shows a code 32. What is code 32?

Thanks.

Bill S.

Bill------


Using the diagnostic protocol in the factory service manual is the way to go as others have suggested. However, with 104K miles I would not be the least surprised if the problem is a failing EGR valve. These things are, basically, a maintenance item. They run very hot and, over time, this degrades the actuating diaphragm. Also, carbon builds up in the orifice and may cause the valve to stick open or stick shut. Some folks will remove the valve and clean the orifice. I don't recommend this, though. I'd just replace the valve.

The valve is available from GM under GM #19210674