I had this issue out in the desert but I tossed it up to bad circumstances all around until it happened again.......twice.

First time (after the desert) I was driving this trail that was uphill the whole way. I stopped for a couple minutes and the Jeep died. It wasn't running too hot. Maybe 220 TOPs. Hour later it fired back up no problem.

Second time. I was doing some highway driving. Stopped at the store. Came back out and it wouldn't start. Walked around for a while (about an hour) and it fired right up.

At the desert and on the trail drive, I unplugged the wire to the ignition coil and held a tester to it while a friend turned it over. No power to it whatsoever.

I've done a fair share of googling and people have attributed it to a few things. Crankshaft position sensor, camshaft position sensor, ignition coil.

Before I just start randomly replacing things, is there any surefire way to diagnose this? And how do I test the sensors and coil to see if they're in good condition? Do I need to run the Jeep hot then test them with an ohms-meter and look for something?

 

An expert on the '95 XJ may come along and answer your questions(s).


That is to say this is a '95 you're talking about.

 

Yeah it's a '95 4.0 Automatic.

 

Check for codes yet ?

 

There's no check engine light but I'll do the whole deal with the key tomorrow and see if it throws anything.

 

Well just an update. No codes thrown. So no idea. If I were to test the CPS sensor, what resistance should it show?

 

http://comancheclub.com/topic/31487-renix-cps-testing/ - not 100% sure if that's applicable to a 95 as well?

Have you done plugs/wires/cap/rotor yet? Grounds? Battery cables? Test your alternator and/or battery yet?

All of those things are suspect. For me, when mine was randomly dying out after driving and shutting it off and it wouldn't start back up - refreshing the battery cables and ground cables did the trick.

Also could maybe even be your ignition switch - might want to spray a bit of contact cleaner in your key hole and shove a key back and forth in it and see if that helps, and then obviously look into changing it out.

 

Stabs, that's just for Renix. If anyone finds the one I posted a couple of times for HO, please PM me! (I accidentally "cut" it from my list, while intending to copy)

 

That's the thing, it'll crank fine. It's just cutting power to the ignition coil for some reason. Hour later and it'll fire right up.

 

Not yours flintstone, but here's one:

https://www.cherokeeforum.com/f51/testing-cps-5563/

 

Mine does the same exact thing it's the crankshaft position sensor!!! That is a common thing that happen in an xj . It run around 60-70$. It's above the transmission on the back of the block and it's a pain to get to it.

 

MMMMM Well, far be it for me to question Blue...he is describing the Renix test>>" Measure across the CPS leads for voltage generated as your helper cranks the engine. The meter should show .5 - .8 VAC when cranking. (That's between 1/2 and 1 volt AC.) If it's below .5vac, replace it"

HO has three...across what? (not sayen it does not work, but I'm skeptical)

I found a test where you check voltage (DC, IIRC), and rotate the crank with a wrench. Back probing I think. When the gap is on the CPS it reads (X), and not on the gap reads (Y).

The resistance test can tell you it's bad, but not that it's good, is what I gather. Worth doing for HO owners! (Renix can just as easy go right to the ACV test)

 

It sounds like the cps, top of the bell housing. Similar problem on my 95, especially on hot days.

 

savagess Next time it does it, try just unplugging-replugging the CPS, see if it starts. Long story, but that has worked for my (now two) Renix for years...No idea why. Might work for HO as well.

 

It did it again and I checked computer codes. It's throwing a faulty temp sensor code. Odd because it'll give me a reading on the gauge.