I have a 92 corvette it won't stay running tried a lot of things changed a bunch of parts. Starts right up every time runs 2 seconds and dies it will stay running if I hammer the pedal down to about 2500 rpm
anyone with any ideas?

 

Codes? Fuel pressure?

 

No codes. fuel pressure 46 psi. also have a new opti,water pump , idle control solenoid,water temp sensor for the head,coil control module.

 

Have you cleaned the IAC valve, (part of the throttle body)? If you don't have the FSM, there are forum threads on that topic.

 

IAC inop. Engine off cycle key to run. Disconnect IAC start engine does will it run at 2k rpm? Injector fuses..will noid light blink in atleast 5 cylinders. It batch fire ECM turns on 4 at a time. IDK iif engine will run on 4. EGR at idle can cause stalling.

 

I've already changed the IAC valve . I did try it with the IAC disconnected it does the same thing dies out after 2 seconds. I also checked all the injectors with a test light they all are blinking.I haven't checked the EGR valve sounds like the thing to do next thanks.

 

If its at idle and stock injectors 46psi is too high. I believe it should be 41?

What do your fuel trims look like? Run it at 2500 and watch the trims.

Why did you install the opti?

Are all these parts your way of diagnosing or other issues that were previously resolved?

When it dies does it fight or shut right off? If it shuts of without trying Id look at ignition. If your fuel trims are high at 2500 I would think a fuel issue.. 46lbs sounds high but I have a 96.

Somehow I doubt there are no codes.. there are some codes that dont give you a CEL until they happen within GM parameters. What kind of scanner?

Any events of any sort before this started to happen? Change anything?

 

Don't know about the fuel trims will have to research that. I changed the opti because the engine died and wouldn't show any signs of life and the water pump was leaking on it I thought it was a no brainer I was wrong still no sign of life .Turned out being the coil module.Then it would start right up and thats when it began what it's doing now, At that point I started checking other things had a good in and out signal of MAP sensor and throttle position sensor and temp probe on water pump and I when to check IAC and broke it thats why I changed that.I found the temp sensor on the head damaged thats when I changed that.As far as checking codes I was using a jumper on the ALDL and got no codes with that method not sure if a proper OBD1 code reader would show something different.

 

Im not sure if you will get all codes with the short thing.. thought that was just the ccm. Someone else can chime in.

So you replaced the opti and it didnt solve it and then the ICM and it started but shut right off correct? I hate to say this but it almost sounds like a bad opti. Your approach is really not great in regards to troubleshooting. Some of it because you dont have the proper equipment.

TPS, and any temp sensor is not going to cause this stuff to my knowledge. Get a good code reader that will read code history as well as current codes would be my recommendation to start.

I would put a scope on the low and high res signals of the opti to verify its working. Im sure you dont have one so the next best thing is a tech2. You can buy a cheap Chinese knock off which will tell you the frequency. The car will run on low res signal but not on high only. Scratch that.. its running @ 2500.. However, I dont know how well it would idle with just the low res signal.

Since the car runs @ 2500rpm your injectors are working and they are working for two seconds at idle. Any black smoke @ 2500?

After it dies at idle does it start right up? (is it flooded?) Verify your pressure regulator is working.. 46psi sounds high.. I thought it was 41 at idle and also engine not running?

I would swap back your ICM to verify that indeed it will not start at all. Doesnt take much to do that.

You need to verify one component at a time and the only way to do that is with the proper equipment. You also should have a factory service manual.. it will refer to the tech2 often so its a valuable tool if you plan to keep the car.

 

Could be the ECM.