Posdeer

I have a 91 Cherokee Laredo 4.0, my son drives it to school. It will randomly die on him while moving or sitting still, then all it will to is crank. Wait a couple hours and it will start right up. I've been told it is the fuel pump but when it won't start you can still hear the pump run when you turn on the key. Can't convince myself that is the problem. This is our first Jeep and are learning as we go. Is there anything else that could be causing this?

Turbo X_J

Any codes?
When it stalls,
1. Verify spark: spark plug wire, shaft of a screwdriver, close to metal, spark?
2. Check fuel pressure with a gauge, what is the pressure is psi?

Force

I had that problem way back on the wife"s '93 XJ country.
Would be just going down the road and it would die. Set for abit and it would start right up like nothing was wrong. Dealer put a gadget in that when it died, I had to push a button to record the code or something for them. All my internet searching pointed to a faulty CPS
(crank positioning sensor) Dealer finally took my word for it and changed the CPS ( under warranty) never had the problem again.

Johnnybanks

I had that problem in a 2000. Turns out it was idling too low and the cable needed to be adjustable

Posdeer

It's not showing any codes when running or after it dies. He says when it dies it's just like you shut off the key. The first night we tried to check for spark but didn't get anything, but it was 9 at night and raining so didn't try to hard, we towed it home that night and tried once it was home and it fired up and didn't have any problems for a week or so.

DFlintstone

Sounds like the CPS which may not "throw" a code. On two of my (different type CPS) 90"s, just unplugging it and plugging it back will make it start. It's at about 11:00 on the drivers side of the bell housing. Yours would have 4 wires coming up I think. If you do change it go with Napa or Mopar, not a place to go cheap.

DFlintstone

Force, I might add the comma there. helping your Uncle jack off a horse!** helping your Uncle jack, off a horse!

gertie240

uncle should not be capitalized, but the proper noun Jack should.
And plus one on the NAPA sensor.

Turbo X_J

Urban dictionary got it right:
http://www.urbandictionary.com/defin...Capitalization
Capitalization is the difference between "I had to help my uncle Jack off a horse.." and "I had to help my uncle jack off a horse.."

Posdeer

Lol thanks, I'll locate the cps and give it a try next time it dies.

DFlintstone

That's some pretty potent medicine there Turbo. I do still like the comma though, maybe a bit too much!

Posdeer....It's always good to fill out your info so we can see it in each post. If it's a manual trans there is some chance you have clutch dust boogieing up your CPS.

Posdeer

Sorry to bring up an old thread, but the problem was a crack in the coil, pulled it off and had a very small crack on the bottom side, replaced and no more problems. Hopefully this will help if someone else is having the same problem.

jordan96xj

Thank you for the follow up.