ktmcherokee13

i need help... its a 97 xj 4wd, we just did a motor swap in it and was going good, but the we lost power to the fuel pump module. idk what to do, any ideas? thanks

ZachsXJ

you mean there's no power to the fuel pump?

ktmcherokee13

yes and it was just working a week ago, all fuses and relays have been checked and replaced, so there all good.

ZachsXJ

check your wiring and plugs. I had the wire pull out of my fuel pump plug and It stumped me because it didn't pull out fully, just enough to lose contact. take a multimeter and chase all the electricals for the fuel pump and somewhere along the way hopefully you find a fault.

ktmcherokee13

alright well thank you very much, ill try that and see what happens

ZachsXJ

do that and let us know if you find anything. I'm glad to help you troubleshoot if that still doesn't find the problem. Electrical gremlins can be a huge pain in the rear end.

duncan0668

When you turn the key to run and do not start the engine the fuel pump only runs for three seconds. I thought I was not getting power to the pump but by the time I turned the key on and got under the jeep it had turned off the pump.

ZachsXJ

thats the "Start" mode where it runs the pump for a few seconds to pressurize the fuel lines. When you turn the key to on it switches to a completely different circuit that is for the "run" mode. In the "start" circuit the pump primes the lines and thats it. Whereas in the "run" circuit the pump runs continuously.

ktmcherokee13

alright well i havnt got to work on it since this post, but the pump isnt coming on at all, cause we put a pressure tester on fuel lines and there was no pressure.

ZachsXJ

did you do this with the key in the on position? if the key was off...there won't be any pressure esspecially if the drainback valve is shot.