I got up this morning and my car wouldn't crank, I figured it was the battery so I jumped it off and drove to school figuring I just left the door open a little bit. Left school, no crank. Grr. Jumped it again, got home turned it off, and heard the fuel pump still wirring! What the heck? I found the fuse for it right next to the battery, but where the heck is the relay?

Any suggestions as to why it would stay on if its not the fuse

It's a 91 bird with 305 tbi

NE help appreciated.

 

Fuel pump relay stuck, or oil pressure switch stuck. Find the relay (not sure where on a TBI engine), maybe on the firewall?? and unplug it, see if the pump stops...if not, find the oil pressure switch (either above the oil filter, or in the rear of the block, behind the intake, towards the drivers side) and unplug the connector there as well, see if the pump stops.

 

Anybody know where the relay is?

 

On a LO3 its on the drivers side firewall. I'm positive Vader just posted some pics of it this past week. Do a search if you need the pics.

 

Umm, under the hood? But seriously, folks...

I'm not positive on a '91, especially a TBI, but the relay on an older TPI is on the left side of the firewall near the brake booster:



According to my reference, the TBI relay should be in about the same place, but there is only a fuel pump relay and the ESC control unit. Your '91 shouldn't even have the separate ESC since it is incoporated into the ECM, so there should only be one relay. Regardless of what you find there, the relay you are looking for should have a five-wire electrical connector with a red, orange, green/white, black/white, and tan/white wires across the connector. If it is an original relay it may still have "FUEL PUMP" or "FP" inked on it.

 

Ok, thanx, maybe I'll find it now, but I did check a couple of relays by my brake booster and neither of them shut it off. So is it possible it could be something else, something that can bypass these relays?

 

This happened on my car. If the relays don't turn it off, it should the oil pressure sender as mentioned above. This sensor sends the oil pressure to the fuel pump. If the oil pressure drops(after a wreck, or low oil) it turns the fuel pump off, so gas doesn't spray everywear(in case of a wreck). It should be right up by the oil filter. It should be black, and cylinder like. The part costs about $50.

 

So the oil pressure sensor flipping out could cause my fuel pump to stay on and by disconnecting it the fuel pump should shut off?

Oh, and I swear I have unplugged every relay in my engine compartment. Unless it's hidden it's not helping.

 

To answer your question, yes...but you need to make sure your disconnecting the transducer that drives voltage to the fuelpump, not just the single line that goe to the oil pressure gauge.

 

Allright, cool, that must have been it, because I stuck the fuse in and the fuel pump came on. Then I took it out, crawled underneath, disconnected the oil pressure sender, cleaned it off a bit and then put the fuse back in. The FP stayed off! woohoo. So just to double check, crawled back under, reconected the OPS and nothing, it stayed off. Took it for a drive and all is good. So I guess some the water or something that I cleaned out of there was shorting it out. But I'm gonna replace the OPS tommorrow anyway. Think this is necessary?

Anyway Thanx tons.:hail: