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90 xj wont stay started


NAXJA Forum User
Crane, Missouri
I have a 90 xj and when it is cold outside it wont stay started unless i hold the key in the crank position but once I let go it shuts right off. I have changed the ignition switch, crank position sensor and key cylindor, removed the ballast resistor, I even tried putting a space heater under the steering column to see if I warmed it up if it would start. that did not work it must be something in the engine. Any ideas?? I NEED SOME HELP! I HAVE ALREADY BEEN THROUGH TWO STARTERS!!
Check your fuel pump relay. And more importantly, check the fuel pump relay socket for corrosion. Flip the socket upside down and look at the underside.

Also check the fusable links beside the battery.

The fuel pump relay is bypassed when the key is in the crank position.
the ballast resistor is necessary. Had the same problem, and it turned out that i just had a loose wire going to the ballast resistor. try installing a new one and double checking your connections.
similar problem... my '90 does the same thing, you can pull the fuel pump relay and put a jumper wire from pin 30 to 87.
putting power to the resistor ballast will keep mine running, but the jumper wire will not
any suggestions?

the fuel pump relay isnt getting power, so i have ran a fused, jumper wire with a toggle swtich to the place where pin 87 on the relay would go.
flip the switch on, start the jeep; shut the jeep off, flip the switch off. its workin for me now
Had the very same problem. It was the fuel pump relay. Switched it out - no more problems - after a week of trying many other things! Thanks for your post. (13 years later!):cheers: