Won't stay started when key springs back

[duckingjeep]

1988 Jeep Cherokee starts but stops running when I let off the key. If I jump the fuel pump module (relay?) it runs fine. Replaced the relay thinking it was the problem, but it didn't work.

1) Any ideas of what to try next?
2) Is it okay to run it permanently jumped?

Thanks

 

[Saudade]

If you turn the key to RUN (not start), do you hear the fuel pump prime, run for a few seconds and then stop?

When you let off the key, does it shut down immediately (like you turned the key to OFF), or does it stumble a bit then die?

Off the top of my head, I'd say ignition switch. It's located at the base of the column. Either the switch is bad, the harness connector is melted (happens a lot), or the switch slipped out of adjustment.

Do not permanently jump the FP relay. That will keep it running and either burn out the pump, or kill your battery.

 

[duckingjeep]

Fuel pump runs in the on position, and it turns over. Then, once I let off the key, it dies immediately.

I will try the ignition switch next. Thanks for replying!!

 

[lawsoncl]

That sounds like the ignition switch needs adjusted or replaced. The switch is under the dash on the bottom of the column, actuated by a rod the runs under the column. You can loosen the two screws and move it for or aft to adjust, but it's also common for them to burn up and need replaced. As cheap as they are, I'd just replace it anyway. https://www.amazon.com/UnayKolb-1977-1993-Cherokee-Briarwood-Ignition/dp/B0D5XH3LY5

 

[duckingjeep]

That sounds like the ignition switch needs adjusted or replaced. The switch is under the dash on the bottom of the column, actuated by a rod the runs under the column. You can loosen the two screws and move it for or aft to adjust, but it's also common for them to burn up and need replaced. As cheap as they are, I'd just replace it anyway. https://www.amazon.com/UnayKolb-1977-1993-Cherokee-Briarwood-Ignition/dp/B0D5XH3LY5

Just ordered. Thanks!!

 

[phydeaux33]

Just ordered. Thanks!!

When you change it just take the extra few minutes and drop the steering column. It can be done without but it will take longer and probably a few NSFW words as well.

 

[duckingjeep]

Thanks for the tip. That makes sense.