mickneel

Hey yall, 96 jeep xj has been stumbling and dying, not starting, and being a real pain in the *** for a while. Have changed and cleaned many things: IAC, throttle body, CCV hoses, new CPS. It wouldnt start sometimes would others and today it didnt start and the pump wasnt kicking on, so went to test the voltages of the wires. Found the two grounds they read good, and found the 5v switched and the 12v switched that shuts off after a few seconds, but there was another wire reading 6.4v. What is that?? and is it too low or high for what it is? trying to figure out before buying a new pump. Thanks

mickneel

So basically what is the 6.4v wire coming from?

seXjay

One runs to your fuel gauge on the dash. Regardless of the voltage running to your pump, in KOEO you should have a signal from the the float in the tank to the gauge on the dash. That may be your 6.4v. Can you hear the ASD relay actuating?

mickneel

I switched around all the relays, moving the starter relay to the ASD and the fuel pump and everytime they all seemed to work fine

DFlintstone

I hate to suggest throwing parts at it, but if you tested ground, and also found a 12 volt that goes off in a few secs you may have nailed it. I've never done it but saw posted sometimes you can whack the tank and a dyeing pump might run once more. If nothing else that might verify for you that the pump is indeed about toast.

mickneel

Update for anyone curious:
Replaced the fuel pump (not the whole assembly) and it started up great and didn't stumble while driving. One of the connectors for the power to the pump was really loose so we soldered that so it didn't move anymore. Could've been that or the pump but the old pump was 20 years old so probably didn't hurt to replace that either. (Bosch pump by the way). We'll see how it runs in the coming days. Hopefully that solved my stumbling, stalling and dying issues.