fuel system

1999 GMC SONOMA
174,000 MILES • 2WD • AUTOMATIC
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DB18765
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what do i do if my fuel pump relay wont engage but the relay and fuel pump are still good
Mar 4, 2011 at 3:05 AM
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WRENCHTECH
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How are you checking it? It only powers for 2 seconds when the key is first turned on so you need 2 people to check it.
Mar 4, 2011 at 3:07 AM
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DB18765
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when i do turn the key on it doesnt do anything but when i put power straight to the relay it works and also when i put power straight to the fuel pump it comes on too i think there may b a problem in the relay/fuse panel under the hood
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Mar 4, 2011 at 3:30 AM
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WRENCHTECH
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Here is the wiring diagram so you can determine why.
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Mar 4, 2011 at 10:55 AM
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DB18765
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would it b a problem if my o2 sensor is bad i know that it is bad because i put an air/fuel ratio gauge on it and the bar jkumps from rich to lean 2xs a second
Mar 4, 2011 at 4:41 PM
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WRENCHTECH
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It's supposed to jump rich to lean to rich, the faster the better.
Mar 4, 2011 at 9:05 PM
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DB18765
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i thought it was supposed to stay at ideal
Mar 5, 2011 at 1:50 AM
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WRENCHTECH
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No, it isn't. the more cross counts, the better.
Mar 5, 2011 at 1:52 AM