Mechanics

CHEVY FUEL DELIVERY

1987 Chevrolet Celebrity

Engine Mechanical problem
1987 Chevy Celebrity 4 cyl Front Wheel Drive Automatic 86,000 miles

I changed throttle position sensor, idle air control valve, tested fuel pump and changed filter. Map sensor was tested and is good. Fuel pressure regulator also was changed. The question is: the injector will deliver fuel until the car just starts to idle then the fuel stops and the car dies. I am lost
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Rkboss82
June 14, 2009.



Hello, any troublecodes? When it stalls, does it restart right away? If it doesn't, have helper crank it, while you check for spark at the plugs and injector pulse. If you have neither, check the crank sensor.

JDL
Jun 14, 2009.
Yes it does restart right away. Runs for approx. 3 seconds and dies. I do have spark and the injector sprays for the first 3 seconds and shuts off. I believe something else is telling the injector to stop spraying so the car dies. If I continuously spray starting fluid the car will stay running and the injector stops spraying. Thanks p.S there were no trouble codes

Tiny
Rkboss82
Jun 14, 2009.
Did you use a gage to check fuel pressure? What was it?

JDL
Jun 14, 2009.
I have not gauge read the pressure but I did hard wire the injector straight to the battery and it sprays like a son of a gun then. I tested the wires from the injector plug and I had 12 volts with key off. I was told when I roll the car over the voltage should go from 12 to 0 and back to 12 in a pulse fashion. When I roll over the car it goes from 12 to 9 and stays at 9, no pulse. Is it possible the computer is malfunctioning? I have checked and changed almost everything you would normally think could be the problem.

Tiny
Rkboss82
Jun 15, 2009.
There shouldn't be any voltage at the injector, with the key off. That circuit goes hot when you turn on the key, the computer controls the injector ground. Did you crank the engine, while checking for a pulse? If using a dmm, it may average what it sees, it won't show zero.

Either the computer doesn't see an rpm signal, something wrong with the wiring circuit, last but not least the computer.

To add, there is a purple wire with white tracer, carries the rpm signal to the computer, should be voltage on that wire.

JDL
Jun 15, 2009.