: No Fuel when key is on only when cranking



caliguy65
03-29-07, 06:55 PM
Hello everyone. I have a problem and hope someone can help.
I have a 84 RWD Coupe with the 4.1 engine. It used to start up and run good but after it sat for a few months now it wont start.

I checked the fuel pump to see if it was pumping and it pumps fine wile cranking the engine but when the key is in the on position it only goes on for about five seconds then turns off.

The car used to also make a clicking sound from the engine compartment when the key was in the on position but since this problem started I don't hear the clicking anymore.
I checked for blown fuses but all were ok. I couldn't locate one labeled Fuel Pump but none of the fuses under the dash were blown.

What could the problem be?

Thanks in advance

danomac
03-29-07, 10:14 PM
There is a fuel pump relay, but if you're getting fuel while cranking it should be OK. I have an 81 with the 368cid motor, and on my car the fuel pump relay is controlled completely by the ECU.

On some other GM cars, the fuel pump runs through the oil pressure switch, so fuel is supplied while oil pressure is present. If your oil pressure switch/sender goes bad you'll see symptoms like you are describing.

I don't know if the above applies to you, but you may want to track down some wiring diagrams to see if that is the case.

The Ape Man
03-31-07, 11:20 AM
Your fuel pump is functioning as designed. It is supposed to pump only for a short time with the key on, engine not running.

The Ape Man
03-31-07, 11:22 AM
Pull out a spark plug and look to see if it tells a story. Check spark at the plug wire too.