Ive searched here, the web and been living out of the FSM for a few days. PLEASE help!!!

1984 corvette, 84k miles, auto.

Problem occurs regardless of outside temp, level in fuel tank, if the engine is warm or cold.

Has both new injectors and a new 85 fuel pump, sock and fuel filter about 6k miles ago. Has a new Fuel pump relay.

THe car will *usually* start. When it does it will run well for a period of time ranging from a few seconds to well over half an hour. The previous owner indicated that it had a problem with the factory alarm that would at times keep it from starting. He suggested that unplugging and replugging the fuel pump harness in would "reset" the alarm. This did seem to work on several occasions though it may simply be a coincidence.

I can watch fuel spray from the injectors then stop. So it is not getting fuel.

THe FSM looks like if the ignition is interrupted the computer will cancel fuel. THis makes me think that it could be an ignition problem or a fuel problem. I am leaning toward ignition but do not fully understand which or how the various related sensors "cut" fuel pump power.

I know this is a LONG message, but I am stumped and will need to use this as my daily driver beginning Monday for a couple weeks.

Thanks for taking the time to read and respond!
-Scott

 

Check for trouble codes. I would guess that if the computer stops firing the injectors because of loss of ignition pulses, it would set a code. If the injectors stop squirting either they are not being fired of there's a loss of fuel pressure. I'm not one of the experts, just another 84 Vette owner.

 

Thanks for the reply. It has no codes (except the gm test code). Im not sure how the alarm works with regards to the ignition. If it interrupts the signal form teh starter switch to the starter solenoid then that cannot be my problem as the engine always rotates fine and strong. When the fuel is not getting to the injectors there is no power going to the pump as measured at the fuel pump connector harness.

I cleaned all the connections I could find under the hood (related and otherwise) and it seems to be running fine now, sure dont trust it but its acting great.

Although it seems to be running fine now I am still all ears as I have LITTLE confidence that anything has actually been corrected.

 

The fuel pump only runs a few seconds when you turn the key on. It establishes pressure in the system. Then when you crank enough to establish oil pressure the pump resumes. I don't remember if the computer has control of the fuel pump. If the engine has not started, the fuel pump will not do the initial few second run again unless the key is off for 10 seconds. Autozone's website shows a ignition module for $19.99. If they're that cheap it might be worth having one on hand. My book says the computer fires the injectors when it receives ignition pulses. It makes sense to me that the alarm would interupt the starter, but it's a guess. The first time my alarm went off, I had no idea it even had one. It was in a restaurant parking lot and I had to read the owners manual to find out how to stop it.

 

THat makes sense about the ignition pulse. I had not figured in the fact that the pump would not be re-energized until the ten seconds.

If the ignition is not firing then no pulse signal would be detected either. I think I will swing and have an ignition switch in hand just in case until the car proves reliable.

I would rather this thing not run well than be running fine without having made any actual repairs

 

Here is a link to a crossfire forum.
They have or had tons of information, but they are going through some kind of transformation and all the post are not showing up. Hopefully it's temporary.
http://www.crossfire.homeip.net

 

Started doing it again. Each time it is with more frequency and it is now cutting off while driving at times. If I let it sit, it will eventually restart. This happens regardless of vehicle or outside temp.

I replaced the ignition switch in a n attempt to "throw parts" at the problem.

Looks like ti is not getting a signal to the fuel pump at times. THis makes me think the ignition may not be sending a signal.

Would a bad ignition control module act like this???