I have a 2008 impala ss with 77000 miles on it that will not start. initial problem was the fuel pump was bad but I have since replaced the pump. the car ran for a few days but has went back out. replaced the pump again and have now learned that I am not getting fire to the fuel pump itself. the pump will start if I connected it directly to a 12v power source. I have tested the fuel pump relay and its good also. another problem that I have noticed is that the battery is not holding a charge either. not sure if these two things are related or not but I am now at a loss as to what could be causing my problem.

If your electrical system is having issues, I highly suggest replacing the battery if its over 3 years old. Once its replaced, conduct a thorough inspection of the wiring from the tank forward. Especially the NEGATIVE pump wire. You may need to get an AllDatadiy.com subscription to get electrical schematics for your car. I think its very well worth the price you pay.

the battery is new, on the 4 pin plug (2 to the pump and 2 to the gauge) going to the fuel pump there is fire going from the hot pin that goes to the fuel gauge but no fire coming from the positive wire to the pump. also tried a new wiring harness.

Then you have an open somewhere between the pump and the relay. Time to start digging.....


Just to make sure, please use a good wire from your test point to the NEGATIVE side of the battery when you are testing for POSITIVE voltage at the harness to the pump please. We need to eliminate if its the + wire or the - wire.

so is it possible that a short on the negative battery wire could cause the problems with the lack of fire at the wiring harness?

No, I want to eliminate the possibility it could be either of the 2 pump wires.

so you have no voltage on the gray wire to the pump? try checking the pump fuse with a meter? sometimes the fuse and relay sockets get loose and dont transmit power properly. the fuse is after the relay so you have to turn on the key while testing because it only turns on for a second or two

used a test light tested the negative wire to the pump and I have continuity.

the fuse for the pump is good. no fire on the gray wire but fire on the purple wire to the pump which goes to the gauge.

gauge and motor are separate circuits. you need to test the fuse with the light if thats all you have, but a meter would be better, because bad sockets cut the voltage down and you would be able to tell