Tiller658

Last night driving down a back road my 94 Cherokee I6 4.0 died on me. Steering and brakes basically locked up and it wouldn't start. Sat for 5 mins and drove fine after that. Did the same thing today but going 65 down the highway, died on the ride of the road. Checked the spark, none at all. Waited two hours to get towed.

What could have happened? Coils go bad? Blown fuse? Only had the jeep for 3 weeks and spend $800 on it, could use some advice.

Turbo X_J

1.) CEL on? any codes.
2.) Do you have a DMM?

freegdr

spark ever come back.

tjwalker

You are experiencing "thermal" (heat related) failure of a component.

The #1 cause of this on the Jeep 4.0 engine is the crankshaft position sensor. If you buy one, do yourself a favor and buy a Mopar unit directly from Jeep. Aftermarket crank sensors are "hit and miss" with a lot of miss.

The #2 cause of your symptom is a flaky ignition coil.

Unfortunately, testing of both of these components may be inconclusive UNLESS you test them immediately after the engine stalls.

Good luck and keep us posted!

Tiller658

What is CEL or DMM?

freegdr

check engine light, digital multi meter

DFlintstone

Sometimes the plug its self for the CPS can be an issue. You might pull it off and put it back and see what happens. Agreeing...if you have a digital meter, and do a resistance check (ohms), on the cps while it's not sparking, and it fails, then you nailed that it's the cps. That's tough though I gather since it might pass the resistance test and still be a problem.

I don't know the resistance values for that one. (200 ohms, +,-- 75, hot, for a different Renix CPS)

Programbo

The best thing about having a 94 XJ is that you can access the computer codes without a scanner. If the CEL (Check Engine Light) is on you can see what trouble codes have been stored.

tjwalker

And here is how to check for codes on your 94...........
--------------------------------------------------------------------------
OBD1 Models: 1991-1995
1) Start engine (if possible). Move transmission shift lever
through all positions, ending in Park. Turn A/C switch on and then off
(if equipped).
2) Turn engine off. Without starting engine again, turn
ignition on, off, on, off and on within 5 seconds. Record 2-digit
fault codes as displayed by flashing MIL.
3) For example, fault code 23 is displayed as flash, flash,
4-second pause, flash, flash, flash. After a slightly longer pause,
other codes stored are displayed in numerical order. When MIL begins
to flash fault codes, it cannot be stopped. Start over if count is
lost. Code 55 indicates end of fault code display.

Tiller658

After some research. I replaced the ignition coil and the crank pinion sensor. $110 for both parts from the part store. Was the sensor.

alnielsen

Both of those went bad on my 94 2 weeks ago. The coil actually had a crack in it.

NorCalJeep

I was going to say CPS, but you got he problem solved :/

DFlintstone

???

DFlintstone

??? Computers.

DFlintstone

So you know it was the CPS, not the Coil?

AND WTF?.....Had a computer glitch...??