Fuel Pump/Relay ?
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Joined: Oct 2005
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From: Western New York

In another thread I suggested a member try unplugging his fuel pump relay to see if it would help with possible flooding/no start condition. So today I decided to try this on my son'* 89 to see if the car would start & if so how long it would run without the fuel pump. I was sure shocked when it started & kept running & running & running. After a little tinkering I decided all that relay does is control the 2 second prime. I'm at a loss as to where the power comes from if you don't need the relay. I have a wiring diagram & it doesn't look like it should run without the relay. Anyone know how this works?
I've not got your car'* circuit diagrams. But on the cars the oil pressure switch provides a circuit for the fuel pump if I recall correctly. That way if the oil runs out or motor quits the fuel pump quits pumping, as in an accident. The prime is only for a couple of seconds.
Thread Starter
Senior Member
Certified GM nut
Joined: Oct 2005
Posts: 1,942
Likes: 1
From: Western New York

You may be right. The Chilton'* diagram for the 89'* has to be wrong. It does show the 92 & 93 getting power from the oil pressure switch. I guess the previous years must have been the same. So the fuel pump relay is just used for the 2 second prime? Can any of the Gearheads confirm this.
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