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Old 07-28-2006, 08:50 PM   #1
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Default Fuel Pump/Relay ?

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?
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Old 07-28-2006, 10:00 PM   #2
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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.
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Old 07-29-2006, 11:44 AM   #3
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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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