No Power to Fuel Pump

'89 XJ, 4.0L, 4x4, auto tranny. I have been recently dealing with a series of fuel pump problems. It started suddenly out of the blue when my jeep began idling rough and taking an extremely long time to crank. I checked the pressure at the fuel rail and found it to be at 20 psi, nearly half the pressure of what it should be. Went to Napa, picked up a Carter replacement pump, replaced the pump and got nothing. So I checked/cleaned the connections on the pump and the ground on the tank, still nothing. I then started probing with my voltmeter and found that I was not getting any voltage to the pump. In the engine compartment I've got approximately 12 volts coming out of the relay. At the ballast resistor I've got .01 volts going in and .01 volts coming out. Is there something inline between the resistor and the relay that could be the culprit? Any other suggestions?

Thanks,
Justin

Hallo. You have to run the motor to have min.of 12 volt at the ballast resistor.
If not,replace it or connect the 2 pins. Is the pump running, when you make a bridge with a piece of wire between pumprelayconnectorpins 87 and 30?:wave1:

Did you check the fuse? I bet the old pump shorted out when it died and blew the fuse. It's probably not labeled "fuel pump" so you'll have to check every single fuse in the block to find the blown one.

I met a group of dudes out in the desert with a TJ that wouldn't start. I had them turn the key from off to on and listen for the fuel pump, nothing. We looked in the owners manual for the fuel pump fuse, and it wasn't listed. I told them to "check every single fuse" and I went back to my campsite and had a cold beer and some carne asada tacos. Went back over there and they're still farting around with it and I said "Did you check every single fuse?" and they were like "No, there's no fuse for it." So I was like whatever and I started pulling out all their fuses, sure enough one was blown, and when they replaced it, it started right up.

The moral of the story is you should always listen to me when your TJ is dead in the desert :looser:

Alright, the pump is not running when I make a connection between the relay pins, also I've gone through all the fuses on the fuse panel and found nothing to be blown. There is no voltage going into the C4 cavity on the bulkhead connector in the engine compartment. So I've got power coming out of the relay but somewhere between the relay and the bulkhead connector something has gone amiss. Any ideas on what could go wrong in between these two items? I made a jumper between the two connections on the ballast resistor and ruled it out as being the culprit. Looking on the wiring diagram I found a wire going to the starter relay that is spliced into the fuel pump circuit. With the key ON I've got no voltage at the connection to the starter relay...is that normal?

Thanks,
Justin

Can you hook 12v straight to the motor for a few seconds and see if runs? Maybe it's DOA.

FYI alldatadiy.com has complete FSM wiring diagrams for every year XJ with the correct color codes even. Saves my ass whenever I have an electrical problem.

Also, you can take a wire and hook it from your battery + to the orange wires at the ballast resistor and it powers the fuel pump right up no matter if the key is on or not - this way you know the pump is def. ok - I did this the other week alond with popping off the hose to my fuel rail and extending it and filling up my ZJ's tank from the XJ that had recently been hydrolocked - fuel pump pumped 3/4 tank in about 5-10 minutes I didnt even have a battery in it - just took my charger and hooked to ground and clipped the positive to the ballast resistor wires that were previosly wired together