Got a '96 Cherokee. All stock. It's a "farm Jeep" in Central Illinois. Virtually never on the road. Rarely sees 30 MPH. Typically used on short trips around a hilly pasture to check on cows and such.

Today it was miserably hot. Temps in the low 90s and bright sunshine. I drove it maybe 20 minutes, then shut it off. It sat for maybe 6 or 8 minutes. When I got back in it cranked over like it always does, but did not fire. After it sat for an hour It started immediately and ran fine.

Drove it out to the pasture, turned around and headed back. Put it in park to open a gate, and it died. Once again it cranked over, but did not attempt to start. Let it sit 90 minutes. It started immediately and ran like normal.

A little over a year ago it was running poorly, and had low fuel pressure. It got a new fuel pump in the tank, and has run reliably since then. So I'm inclined to think it's electrical in nature. But I don't know where to start troubleshooting.

I don't want to just go buy parts and start changing stuff out. I'd rather try to figure out what's wrong. Am hoping some of you have run into this problem before and can point me in the right direction.


Thanks for any help you can offer.

 

Sounds like a crank sensor that is bad you can check it by poring water on it to cool it down if it starts up then that's the problem .

 

Is there a thread about where to find it? I have no idea where it is.

 

 

I've seen a few causes of this.

- Defective fuel pump, more specifically, defective fuel pressure regulator that's part of the fuel pump assembly on 96 model years.
- Heat soak where fuel vaporizes in the fuel rail. You'd need to wrap your fuel rail and fuel injectors with stuff like what DEI sells.
- Crankshaft position sensor

 

Thanks to all of you who helped.

The thought that the CPS was the problem seemed to be most prevalent. And I'm reasonably certain that it wasn't fuel related. So I got a new CPS and installed it today.

I have not had time to test drive it. If that wasn't the problem I'll check back in this thread.

 

What a cliffhanger!!

Also let us know if it DID solve the issue

 

I’d love to know if it solved the issue as well. I was out on the trail today in my 93 and had a very similar experience. Shut it off to go walk ahead on a new trail, went to start it and same thing crank no start. I rolled down the hill I was on, waited a minute and it fired up and ran fine. Later on I shut it off again to stretch my legs by some water, 5 mins later, crank no start. I poured water on the rail thinking it could be vapor locked and I could cool it down but it didn’t seem to help much. Maybe 10 min later with the hood up, more water and temps around 180 it turned over and ran fine. It didn’t die on me thank god. I’m thinking vapor lock? But I’ll try this if it fixed OPs issue.

I’ve also noticed longer crank times on cold starts but I will have pressure at the rail even when cold so I don’t think it’s the FP check valve.

Right before the crank no start

 

Bet you weren't jumping for joy when it started to crank/no start while being out on a trail in the middle of nowhere

When you say having pressure, you mean you pushed the shradervalve?

Just curious: Did you also try starting it with the pedal to the floor?

 

oh crank no start in the woods with wife and kids was a whole new kind of “pucker moment” lmao


yea I have pressure at the shradervalve when it’s cooled off. I didn’t think to check it on the trail at the time. I did not try with foot to floor but I did feather the throttle while cranking and it seemed to have no difference. I’m going to check fuel pressure at pops house sometime this week as I don’t have the gear. I’m thinking a weak fuel pump could be part of the problem? What gets me is once it starts it runs absolutely fine. That’s why I don’t suspect failed electrical components but maybe something under the hood is sensitive to heat?

 

As Roler requested, I thought I'd come back and let you know what happened.

It's been about 30 days since I installed the new CPS. So far it's ran flawlessly.

We have not had any 90° or more days when I drove it. But I have driven it enough some days that the engine should have been at full operating temperature. So I believe the CPS solved the problem.

 

Thanks for coming back and letting the flock know how this went . It might even be a thread with closure!
30 days running sounds promising

Just in case people find this thread decades from now: what brand CPS did you put in?

 

I got a CPS from the local NAPA. I don't recall if there was a brand name on the packaging.