fuel pump not engaging
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fuel pump not engaging
i have an '08 f350 6.8l v10. the fuel pump is not engaging when i turn the key. checked all the fuses and switched relays. changed vapor solenoid in charcoal box, drive module on rear frame, fuel pressure sensor on fuel rail. i have removed fuel pump from truck and works with direct current and has power to it when connected. i connect a ground directly to it and it continues to run. is there something I'm missing or do i have a PCM problem
Tuned
Joined: Apr 2001
Posts: 417
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But are you then saying that you have power to the pump while it's in the truck, but it only runs if you rig up a ground to it? If that is the case, it sounds to me like you have a loose ground somewhere. I don't have an 08 diagram to look up for you, but if you can find the ground location for the pump on that model and make sure it is good or that you don't have a damaged wire. Are there any other things not working correctly?
Edit to add that you could have a PCM problem with the grounding issues. Especially if the pump is the only thing using that ground that is not working. (again, no diagram so I don't know if anything else uses the same ground as the pump on your model) Some of those circuits are completed by the PCM closing a ground. So if it is not doing that, directly connecting a ground like you did, bypasses the PCM and makes the pump power up.
Check the crash switch like wae suggested, but that should cut power and not the ground, so if you have power at the pump, then the anti-rollover (crash) switch is good and the relay should be too.
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Rich C.
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
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Aug 11, 2003 11:07 PM
