CPS and ignition coil intermittent loss

[Papa_SmurfTJ]

Having some odd problems with my 2004 Jeep TJ with a 4.0. 5 Engine codes related to Cam/Crank sensors and Ignition Coil.

Drivability: Once engine hits temp, small backfires and bucking when accelerating. Then it progresses worse.. When either slowing down or coming to a stop, the engine will start to stall out or fully die. The kicker, some odd times when accelerating at a stop sign/light all primary coils (A, B and C) will throw a code bit engine continues to run but when accelerating the engine has no power and feels like a constant rumble, totally has an abnormal tone..

Codes: Started receiving codes for Camshaft Sensor/Crankshaft Sensor Intermittent Loss (P1391 CEL)

Code P0340 for the Camshaft Sensor.

Codes P0351, P0352, and P0353 for the whole ignition coil go off.

Diagnostics:
I first started looking at all the connectors/wiring and including engine grounds and nothing out of sorts. Everything looked as it should. So I decided heck let’s replace the CPS, CKS, Ignition Coil with Mopar. Also did the Spark plugs and even the Fuel Pump (Pump has been running rough for a while so needed to be replaced) but nothing fixed the problem.

So I replaced the OPDA (Oil Pump Drive Assembly) with a Crown Automotive one, yet still throwing all the same codes. I dug into removing the entire wire harness and check every wire to find no problems with the wiring.. Next thing has to be the PCM correct?

Sorry for such a massive prognosis on my Jeep.. This has just been happening for 2 months now and i’m tired of searching and having no luck:/ Any advice is more than accepted!

 

[CharlesHS]

I would remove the three 32 pin harness connectors from the PCM and inspect for oxidation on the pins or harness connector clips.
Inspect the wiring harness from the PCM that is routed along the firewall and that is routed around the threaded head stud in the right rear corner of the head. This head stud is known to rub thru the split wire loom and wiring insulation causing shorts to ground.

 

[JKP]

And the wiring over the dip stick.

 

[Papa_SmurfTJ]

I would remove the three 32 pin harness connectors from the PCM and inspect for oxidation on the pins or harness connector clips.
Inspect the wiring harness from the PCM that is routed along the firewall and that is routed around the threaded head stud in the right rear corner of the head. This head stud is known to rub thru the split wire loom and wiring insulation causing shorts to ground.

I appreciate the reply, i’ll take a closer look at the back head stud.

 

[Deepsouthgt]

Look at my most recent thread. I am having the same problem. Mine started after driving in a monsoon rain and then the jeep sitting in a parking lot for 21 days with the cover on it. I have replaced everything that was throwing a code and then some. Even the PCM. Found some melted wires on transmission sensors. Replace the sensors and repaired the wiring the right way. Most recent thing I found last night was the ignition coil has a crack in the plastic body on the side. When I checked the low side after taking it off the engine, the resistance was higher than the range listed in the Chilton manual at 1.5 ohms. It was slightly warm from running for a few minutes, pulling it into the barn. When it cooled down, it was at 1.2 ohms, which is the top of the range. I may be replacing my coil next. Mine will run like a raped ape until the engine warms up, then it will not maintain 45mph. It sputters and bucks so hard, its like a plug wire is off. Does this sound like any of your issues?

 

[JKP]

Sounds like a bad coil. Exactly what my YJ would do with a bad coil. Only one that I found that would last any length of time was the Blue Streak one.

 

[Deepsouthgt]

Sounds like a bad coil. Exactly what my YJ would do with a bad coil. Only one that I found that would last any length of time was the Blue Streak one.

Thanks. I will try that tomorrow and post an update.

 

[wesley697]

Any update yet Deep? Having the same problem I'm at a loss

 

[Geeknahalf]

Sorry for reviving old post, pls don't bash me too bad. I've been trying to figure out what this was on my 04 TJ for over 8 years now, and finally found it today. According to google, this may be cause for your issues.
UPDATE: Google also says it's just to suppress radio noise, and prevent coil from feeding back a jolt that may melt wiring harness: https://www.wranglerforum.com/threads/filter-capacitor.184152/