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Q: No start, lack of power to fuel pump

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My truck just died while driving, towed it home and installed new fuel pump. Drove it a week and the same thing happened. Engine just quit while driving , replaced fuel pump and drove it for a week, engine quit again. Towed home pulled pump and only have 6.9 volts with key on. Cranks no start . Pump Hase no sound, no pressure at fuel rail. Pump works when running 12 volts direct

My car has 128000 miles.
My car has an automatic transmission.

Hello. Most fuel pumps require 12 volts to operate, and will not function properly with anything less. This lack of power is likely the reason why there is no fuel pressure and why the vehicle is not starting. The symptoms you describe are commonly caused by an issue with the vehicle’s fuel pump relay or ignition switch. These are the two components that control power to the vehicle’s fuel pump and can cause the pump to not work if they malfunction or fail. I would start by testing the fuel pump relay, which is located in the vehicle’s engine bay fuse panel, and then looking at the switch. If these check out then it may be possible that there is some sort of wiring issue to the pump. As electrical issues can sometimes be difficult to diagnose, I would recommend having a professional technician, such as one from YourMechanic, come to your location to diagnose what may be causing the issue.

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