i only have 4.75 volts going to fuel pump. i have checked the fuel pump relay and the auto shutdown relay. they both work when i put power to them. i also replaced the main ground wire going to engine and the ground going to chassis. still not enough power going to fuel pump. i checked the fuses in the power dist. center under hood they are all good. so is there anything else that i can check for like fusible lins or etc... all all help would be greatly appreciated.
2007-01-03 15:24:58 · 4 answers · asked by cornell 1 in Cars & Transportation ➔ Car Makes ➔ Jeep
did you check the ohms on the positive side there may be a wire that is half broken
2007-01-03 15:34:15 · answer #1 · answered by edward m 4 · 0⤊ 0⤋
Sounds like the fuel pump ballast resistor (aka fuel pump resistor) is defective. In the circuit between the fuel pump relay and the fuel pump motor on your Cherokee there is a ballast resistor and a ballast resistor bypass relay. During start mode and under wide open throttle conditions your ECM bypasses the ballast resistor via the ballast resistor bypass relay and delivers full voltage to the fuel pump motor. But after start-up under normal throttle conditions the fuel pump motor is energized via the fuel pump ballast resistor which lowers voltage delivered to the fuel pump to reduce the pump speed to normal running mode, which in turn reduces pump noise and extends the life of the pump. After start-up there will be no power to the fuel pump if the fuel pump ballast resistor is defective. The fuel pump ballast resistor on your Cherokee is located at the top of driver side fender apron near the firewall. It will be a white rectangular ceramic type ballast resistor with a spade terminal on each end. I think it is a 1-ohm ballast resistor but you better check with the dealer parts department to be sure you get the correct one. In the meantime, until you get a replacement, you can just unplug it and jump the 2 wires together and run the fuel pump full power. But understand that will shorten the life of the fuel pump and so I suggest you replace the ballast resistor as soon as you can. Oh! And of course you should check the ballast resistor connectors first. You might get lucky and find that the problem is just a faulty connector.
2016-05-23 01:25:11 · answer #2 · answered by ? 4 · 0⤊ 0⤋
What voltage do you have across your batt. terminals ?? If you have 4.75 volts it has to come from the battery. That means you definitely have a circuit between the batt. and fuel pump. Where the loss might be is not possible to figure from here.
2007-01-03 16:26:04 · answer #3 · answered by tronary 7 · 0⤊ 0⤋
check your alternator. it should be pumping about 14-15 volts. if not, then that is your problem. hope it helps.
2007-01-03 15:37:43 · answer #4 · answered by Anonymous · 0⤊ 0⤋