Okay here goes my long winded and hopefully not too stupid of a question:

Sometimes when I have driven my car a distance that requires me to drive a half hour or more (this never happens after a short drive) the fuel pump won't shut off after the car is shut off, it buzzes away until I call my husband out to disconnect the battery to kill it, lol.

The car has also been more sluggish at acceleration lately (happened around the same time the fuel pump started malfunctioning) and the oil gauge has quit working too.

What could be causing this?
Are these problems related in some way or are they separate?

Any help anyone can give me would be greatly appreciated and if I am in the wrong forum please direct me to right one. Thanks!

Amy

 

Wow I have never heard of that. My guess is that the pump is on its way out. It should still shut off when the car is off though. I do know that A bad oil sending unit will cause a fuel pump to delay but nothing like you described.

 

Malf. fuel pump relay or the backup oil pressure activated switch sticking would be the most likely suspects. Those are the only two switched power conduits I can think of that would cause the pump to run on. Could also be chaffed wires that are making contact with eachother but thats less likely. Both the relay and backup switch are realatively easy to test. The fuel pump relay is on the firewall while the backup pressure switch is tapped into a passage above the oil filter. If your husband is at least semi-knowledgable he could test each by unplugging the connector and see if the pump runs on. If not, a service station should be able to perform the test and fix the problem for a nominal ammount. If the fuel pump is dead or worn out from all the excessive running then repairs will be more expensive.

 

Teh oil gauge quitting is probably from a bad sending unit, which is another easy to replace part. Its screwed into the chinawall next to the dist. in the rear of the engine compartment.

 

I've had this exact same problem...

On my '89 IROC the switch and gauge sender are the same thing, there is no sending unit at the back of the intake just the one above the oil filter (bottom rear of the driver's side of the engine). I had the sender fail internally somewhere and oil began to leak out thru the connector.

Replace this thing and your oil pressure gauge will magically come back to life and your fuel pump will quit its incessant whining, I promise....

Drew
'89 IROC L98/M6

 

AFAIK, none of the tbi cars came with the integrated press. sender/switch. Both are seperate.

 

TBI trucks use the same sending unit for both.

 

Hey drew, this is a really old post but I'm going to do these checks and see if that will fix my problem I was repairing some wires from where the PO like an idiot cut the wires and added an inline switch to turn the FPump on and off. but when I first bought the car the fpump still would prime and shut off like it was supposed to. then when I went under the hood and used wire connectors to hold the wires instead of tape then the fpump started to prime and will not stop until I shake the relay. even when I take the key out I have to shake the relay. I told my wife its probably getting stuck. It is 21years old. if that does not do it for $17 then I will test the oil pressure switch. But it only started when I bothered the relay. thanks everybody!!!!!!!!