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91 corsica 3.1 fuel pump not pumping

04-29-2009, 09:58 PM
3.1 mpfi ...it has been sitting for about 2 years and ran good when parked.. i was told the only thing wrong with it was a battery drain if parked overnight, (dead battery by morning).. i replaced the fuel filter and no fuel is pumping into the new one..i tried cranking it with no filter to see and nothing.. is their any way to directly power the pump from the data port? (i have done it with my camaro). would the relay kill the pump? any other suggestions would be great

04-29-2009, 10:07 PM
Not aware of a way to do that, and sorry to say we no longer own our 91 or the GM service manual. However there is a relay on the firewall that may be sticking. Probably gonna have to look in a Haynes manual to find it as I remember there were 2-3 similar relays. Ours acted up the last year we owned it.

05-01-2009, 12:02 PM
I have the manual in front of me.
If you suspect a problem with the fuel pump, verify the pump actually runs. Have an assitant turn the key switch to on- you should hear a brief whirring. If it doesn't come on check the fuel pump fuse. If it is good check the fuel pump relay. To test the relay start the engine and let it idle then disconnect the the fuel pump relay. If the engine does not continue to run the oil pressure switch is faulty. If it continues to run reconnect the relay and and turn off the ignition. With a test light probe the fuel pump test terminal. If the light does not come on the fuel pump circuit is okay. If the light comes on the oil pressure switch is bad.
That's what the manual says. I don't know how you would start the car if the pump doesn't come on. I would do the fuel pump test lead first just to see if the pump kicks on and I would unplug and replug the connectors on the fuel tank (may be a bad connection). I would also check the wire to the oil pressure switch since the manual mentions it.

05-04-2009, 11:39 PM
Some GM cars around this year had a fuel pump connector to jumper the fuel pump. You can always remove the fuel pump relay and jumper it with a wire into te terminals there.

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