Electric fuel pump

ROMA SMITH

MEMBER
2004 PONTIAC SUNFIRE
90,000 MILES

I own a 2004 Pontiac Sunfire. My issue is crank no start no power to the fuel pump. I started with the fuel pump relay switch. I established the control side of the circuit was good and that the supply power back to pump was good. A new fuel pump was installed pervious to this no start issue. So I wanted to directly check the pump itself. So on the bottom side of the car I disconnected the fuel pump wiring connector from the underside. I wired two jumper wires directly from a good 12volt battery neg and pos posts. I then wired neg to black ground terminal and pos to the gray power terminal on the connector going straight to fuel pump. The fuel pump came on. I tested the power to fuse on inside driver panel, FP/inj, it was good. Now on the under side the I did get a reading for ground integrity, but nothing on power?Under back seat I used a paper clip to check power nothing? Where is the problem

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

If you use a jumper wire at the relay between the gray and pink wires, does the pump run? Take a look at the attached pic.

Also, do you get a low voltage signal from the PCM to the dark green and white wire at the relay which is what actuates it to send power to the pump?

Also, confirm continuity to ground at the relay.

Let me know.

Joe

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