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Fuel Pump No voltage

2K views 7 replies 4 participants last post by  evilpebble 
#1 ·
I have a 1994 Jeep YJ that does not send enough power to the fuel pump; 4.72-5v. We have been able to confirm our fuel pump works, but there is something not sending the right amount of power to the pump.

One issue that has arisen since this has been the Fuel Level Gauge no longer works. Could this lead to the problem?

We checked EVERYTHING: Relays, plugs, followed wires, tested continuity from the fuel pump.

It's a huge headache and needs to work by Friday.

We have one suspect, a loose wire in the engine compartment. See images:


 
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#3 ·
No help on the FP problem....But the blue plug you have there is for the hood light. There's an underhood lamp on a mercury type switch that turns on when the hood is up. I think I have 2-3 various plugs that aren't plugged into anything on my 94. Common harnesses cover all the options -- leaving a spare or two if you don't have something.
 
#4 ·
it's basically a closed circuit so everything must work for it to function properly. just trace the wire back to the gauge from the pump inspecting it as you go. after that, if your sure the pump sensor works, the wire isn't degraded or compromised, and the ground is set right it might be an internal problem in the gauge cluster assembly itself. trust me, had to trace and rewire just about my whole jeep, but everything works like it should for me now.
 
#6 ·
Well I'll see if shunting the gauge works. If not I'll wire it to something that's hot while the ignition is on.

Do you think if I wired the fuel pump in line with the ignition coil it would cause too much drain and reduce spark? I'm not sure if it would, but it seems my only option beyond setting it on a toggle switch.
 
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