HeavySweep

Hey guys, this is going to be my first thread. Not because I haven't used the forum before, but because my XJ has been so reliable, I've only ever needed to do routine maintenance to it. That changed this winter. I was roaring up the road heading for lunch at our favorite deer hunting lunch-stop, when my 97 XJ with the 4.0 fell flat on its face going up the hill. I pulled the codes off with my scanner I keep in the glove box, and it relayed 2 codes dealing with the ignition coil. I'm an idiot and didn't record them before I erased them, but replaced the ignition coil that night, and it still wouldn't fire.

Since that night, my replacement parts are as follows : NEW OEM crankshaft position sensor, NEW OEM camshaft position sensor, NEW OEM ignition coil. I have good fuel pressure, however I have no spark coming from the new ignition coil. I have checked my 5v references to the CPS, CamPS, MAP, and TPS, and they all have 5.14v with the key on. I have checked the DG/OR wire in Pin 1 of the coil connector and found it indeed has over 12 volts when cranking. The ASD system checks out, I checked it even though the ignition coil gets power from it. My PDC fuses and kick-panel fuses have all been tested and found to be good.

While checking wire integrity, I did come across the connector to the camshaft position sensor had a MAJOR issue: ALL 3 wires were bare for about an inch out of the connector. My question is: with those 3 wires touching, is it likely my PCM is toasted in that circuit? I've uncovered all the wiring, tested with a multi meter, and the PCM acts fine. It just has no spark. Sorry for the length, just trying to show an attempt at doing all the diagnostics I can.

Can this kill a PCM?

Brian Mcclung

if you have the wire harness appart to the PCM I would just check those pins. I'm having siminal problems on my 99 but I had more wire damage and thought I repaired proper. and replaced PCM AND STILL NOTHING.. Good luck.

Roler

Crank no start
Or no crank at all?


So you have 12V from the ASD?
Done this test?
Post #5 in below thread

https://www.cherokeeforum.com/f2/ignition-coil-testing-procedure-230526/

Brian Mcclung

I used a different relay from cooling fan and tried. crank no start. nss bypass . new rotor. new pick up plate. new crank sensor. new pcm. no voltage to plug at harness side of coil . tho I definitely had harness damage. I crimped and heat shrank damaged areas. need to find a pinout of pcm and wire harness.

Brian Mcclung

yes tested for 12 v at plug. and no go. asd seams good . grounds don't even look bad. but at this point I'm pising in the wind lol.