Fuel pump priming issue, what controls it????

[fbodlovr]

Ive asked this plenty of times, and it seems like nobody really had much of an idea, so I thought I might ask one more time to see if someone can answer this for me.

Heres the issue im having. When I turn on the key, the fuel pump doesnt kick on to prime. I did replace the fuel pump relay, and when the ignition is on i can put power to the relay to trip it and get the fuel pump going. Also, if the battery lasts long enough, it will crank long enough for oil pressure to build up, and then the fuel pump will kick in. I know there is a fuse for the fp/inj and it is good. Now, I have looking at a wiring diagram on gnttype.org and found there is a prime wire close to the relay? What exactly controls the fuel pump with priming it, and knowing when to kick it off? The ecm is upgraded to the 87. PLEASE help. This is killing me. Also, anyone know where I can get some new door pins with bushings, AND new rollers?

 

[buickpower]

well, the oil pressure switch is wired in parallel with the fuel pump prime circuit. that is in case the relay fails, the switch will close when you finally crank long enough to build ~4psi oil pressure. however as long as the relay is good, the pump should prime just fine. I'd check for a faulty trigger wire.

 

[fbodlovr]

The relay is good. but now, where is the trigger wire?

 

[Jerryl]

You got mail. Send you a wiring diagram so you can see the inputs. Too large to post.

 

['71buickg.s.]

can you send that diagram to me too? jdd0688@hotmail.com

we're having the same problem.

 

[Jerryl]

[QUOTE='71buickg.s.]can you send that diagram to me too? jdd0688@hotmail.com

we're having the same problem.[/QUOTE]
E-mail send

 

[fbodlovr]

Did anyone ever figure out what causes this????? 71buickgs, you find anything out on yours? I havent tried it yet, but I kind of wonder if the problem might be the main harness coming threw the firewall.

 

[Sam Colalillo]

This may help

Sorry I am to lazy to type, but Read both these threads. I think they will clear some things up for you .


thread 1


thread 2

let us know what you discover.