I have a 1999 sunfire GT 2.4 l I had a bad motor replaced the motor and hooked everything back up when hooked battery back up fuel pump engages and will not shut off. I unplugged fuel relay and fuel pump fuse. The fuel pump still continues to flow Im lost I checked the wires everything looks good but like i said im lost and any help would be appreciated. and to note everything else on car was fine before just had a bad piston so replaced motor. please help on here or send me an e-mail therock snipped-for-privacy@hotmail.com Thanks in advance Brian
Fuel Pump wont shut off
Jun 23, 2006
3 Replies
Check the oil pressure sensor and wiring to it. The oil pressure sensor has a set of contacts that are wired in parallel with the fuel pump relay (acts as a "fail safe" so your engine will continue to run if the fuel pump relay fails while driving).
Regards, Bill Bowen
"disturbed1980" wrote:
Shep,
I'll defer to you regarding the wiring of that car - I didn't have my Sunfire manual handy and did this from memory (all the older 4 cylinder Sunfires and most other GM engines have that oil pressure switch backup fuel pump feed). I looked at the Service Manual diagram for that Sunfire and you are correct.
Rock, if you have a voltmeter handy, check for the presence of +12V on the gray wire going to any of the fuel injectors: this is the same feed that goes to the fuel pump. With the ignition switch turned OFF, this voltage should be zero.
I'd go with Shep's idea that you've got a short to +12V to that gray wire somewhere in the engine compartment. My first guess would be to look very carefully around the throttle body and the fuel injectors - there are some items in that area that get a constant 12V feed.
Regards, Bill Bowen Sacramento, CA
"Shep" wrote:
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