Looking for advice from Corvette enthusiasts...

[pjt]

Hi all you Corvette enthusiasts!!!

I recently purchased a 1988 Corvette. She is an automatic and when she runs--she really runs BUT
lately I have been having a terrible time with her. She wants to start but then stalls out immediately. I have had her towed 3 times to 3 different garages (2 of them being local Chevrolet dealers) but no one seems to be able to determine what the issue is. I have replaced soooooo many different parts but the issues still remains. Here is a list of the parts I have replaced so far:
Battery, mass airflow sensor, spark plugs, wires, cap and rotor, fuel pump, fuel filter, fuel pressure regulator,intake hose,lock cylinder and 2 new vat keys, numerous other "sensors" that I was told were bad. I am at a loss here. I am trying to find a "seasoned and well experience corvette mechanic that knows the older models". She has not started since Christmas day. I don't have the history on her but obviously there is something wrong. She wants to start---but will not remain started. Any ideas?????? Spring is fast approaching and I want to drive her--not look at her taking up space in my garage.....Any help will be appreciated.....:ugh

 

[Rob]

Welcome to the Corvette Action Center!

I'm going to move your thread into the C4 Tech forum for greater exposure...

 

[gmjunkie]

Look like the only thing you haven't replaced is the Ignition Coil and Ignition Module in the distributor!~ :L

Both of them can have the same symptoms your having,Replaced allot of L98 ignition modules in my time!

 

[hoosierdaddy]

Welcome to Corvette Action Center

Welcome aboard, glad you've joined us. gmjunkie is about as seasoned as you can get I would listen to him for sure

-Bill

 

[vetteoz]

Here is a list of the parts I have replaced so far:
Battery, mass airflow sensor, spark plugs, wires, cap and rotor, fuel pump, fuel filter, fuel pressure regulator,intake hose,lock cylinder and 2 new vat keys, numerous other "sensors" that I was told were bad. I am at a loss here.

Sounds like your mechanics work on the
" keep replacing parts till you find the faulty item " principle rather than diagnosing the ACTUAL problem.

Start by pulling the engine fault codes to see if anything showing.
Report back any you find

See
C4 Corvette Diagnostic Code Recovery Techniques

 

[pjt]

Sounds like your mechanics work on the
" keep replacing parts till you find the faulty item " principle rather than diagnosing the ACTUAL problem.

Start by pulling the engine fault codes to see if anything showing.
Report back any you find

See
C4 Corvette Diagnostic Code Recovery Techniques

The first garage I had her towed to---hooked it up and stated it was a "security" issue and he does not work on security systems so I had it towed to a Chevrolet garage and they told me it is not a security issue---it was a bad mass air flow sensor (which I replaced and it is no better).

 

[pjt]

Look like the only thing you haven't replaced is the Ignition Coil and Ignition Module in the distributor!~ :L

Both of them can have the same symptoms your having,Replaced allot of L98 ignition modules in my time!

I replaced both of those items---no luck.....she still does not start....she wants to start but just will not stay running....SOOOOOO frustrating......

 

[vetteoz]

..she wants to start but just will not stay running....SOOOOOO frustrating......

So pull the codes yourself and see if anything present.

The fact it cranks over means it is possible , but highly unlikely that it is security related
Are you mechanically minded.
Here are some tests to do to check the above mentioned Ign control module which will if faulty prevent the injectors from spraying fuel

Part 1 -GM Distributor Mounted Ignition Module (ICM) Test.

 

[vet7801]

Injectors

You might want to try and check the resistance of the injectors. The injectors fire in two banks, 1-3-5-7 and 2-4-6-8. If an injector is shorted or way out of spec it kills the whole bank from working. The specs are 15.8 to 16.6 ohms at 65 degrees. Start by unplugging all the injector leads at the injectors. Have a good digital meter and check across the terminals on each injector. With age the resistance changes, so look for similar reading among the injectors. Any injector out of range leave unplugged and plug the good ones back in. Try to start the engine, it won't run real smooth but it should run. I have had several cars I've working on in the past with this problem, so this might help. You should also check to see if the injectors are getting power and ground at the injector while you have them unplugged. With the key on, touch each lead with a test light hooked to a good ground, one of the two leads should light the test light. If that happens it shows injector fuse # 1 and #2 are good and supplying power to the injectors. Now you need a node light plugged into the injector connector, crank the engine over and check them one by one. They should all flash showing that the ECM is receiving a crank signal from the dist and firing off the injectors. Hope this helps.

 

[89blackvette]

Stalls

I am not familiar with the Corvettes! Does the oil pressure sensor also send voltage to the fuel pump? I have an 87 Fiero and it works like this. Fuel pimp comes on for 2 seconds to apply pressure to the injectors, after that the voltage for the fuel pump goes through the oil pressure sensor, if the sensor is bad it will not allow fuel pump to run. This does not allow the engine to run with no oil pressure. As you can see this would cause your exact symptoms. I may be way off base here just a thought. Good luck with it.

 

[vetteoz]

Fuel pimp comes on for 2 seconds to apply pressure to the injectors, after that the voltage for the fuel pump goes through the oil pressure sensor, if the sensor is bad it will not allow fuel pump to run.

The OP switch is wired in parallel to the pump relay as a backup should the relay fail ; there is no " fail safe " function related to oil pressure( the input shown to the ECM is solely for monitoring the pump voltage )
So long as the relay is working correctly , the pump ( thus engine ) will run even with no oil in the engine