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Discussion Starter · #1 ·
The last few weeks I am driving down the road and my jeep is cutting out and or misfiring and the check engine light has come on. Upon start up, the light is off but after a few minutes or less it starts misfiring/running rough again. Pretty sure its electrical. I get code 41 besides the usual 12 and 33 when doing the key diagnosis. So I took my alternator out and had it tested at Autozone and the guy checked it 3 times and said it was fine. I also took in my battery and it too came out clear. I have replaced the TPS,CPS, o2 sensor and new plugs at .035. My next guess is the coil or plug wires(which all appear in good shape). I have the 4.0 6 cylinder. Any insight would be most appreciated.
 

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First thing to do...clean all your grounds(firewall, block, alternator) and battery cables.

Then remove, inspect, and re-attach related connectors. Many times you can find some simple issue while doing this. The other CPS(Camshaft Position Sensor) in the distributor tends to see broken wires or oil contamination so give that a good look. MAP sensor wire damage/looseness will give you cutting out issues, too.

We can go from there...
 

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Hey DREDnot, what's with the distributor cap?
I see the JB Weld and the left plug wire tower seems to have a hairline crack around the base.
Then the tower on the right has that orange goop on it.

Is this something you took off a recent purchase or perhaps a customers Jeep?

Just wondering.

Good Luck, L.M.
 

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Discussion Starter · #5 ·
Update!!!

Well earlier this morning I replaced the coil and distributor cap and rotor, as well as new spark plug wires. Still having the same problem. So I said to heck with it and replaced the alternator..... guess what it stopped. So apparently something was failing with the alternator even-though the Autozone test showed it was o.k. Running much better now and no engine light. for grins I did the key test again and got codes 12 and 33. also got 11 and 54? Gonna look them up. But on the bright side code 41 is gone. No check engine light either.:beerme:
 

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Hey DREDnot, what's with the distributor cap?
I see the JB Weld and the left plug wire tower seems to have a hairline crack around the base.
Then the tower on the right has that orange goop on it.

Is this something you took off a recent purchase or perhaps a customers Jeep?

Just wondering.

Good Luck, L.M.
That was the cap on my sahara when I bought it. I don't know what it was, but it had the consistency of sand.



This was on the inside of just that one, also

It ran fine, but my SOP is to replace all tune up components, cooling, fuel system, yada, yada, so this was what I found when I was disassembling things. That hairline crack was actually just a grime ring from the boot. The JB weld was from fixing the fuel inlet pipe on my Vulcan carb.
 

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replaced the alternator..... guess what it stopped. So apparently something was failing with the alternator even-though the Autozone test showed it was o.k.
I have never trusted alternator and starter tests at these places. Its right up there with the new automatic key duplicating machines.
 

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First thing to do...clean all your grounds(firewall, block, alternator) and battery cables.

Then remove, inspect, and re-attach related connectors. Many times you can find some simple issue while doing this. The other CPS(Camshaft Position Sensor) in the distributor tends to see broken wires or oil contamination so give that a good look. MAP sensor wire damage/looseness will give you cutting out issues, too.

We can go from there...
I want to say thank you to DredNot for this bit of advice. I have not messed with my Jeep since June 2016 because the engine would just die for no reason. Sometimes it would start back up, others it wouldn't. Did this 12 times on a 20 minute drive home from a friend's house last year and that was the last time I drove it. I haven't had the time or the energy to try and figure out what was wrong until recently when I came on here looking for someone else with a similar problem. My battery was also dead, so after swapping in a new battery (free replacement from PepBoys, got it in just under the 3 year deadline!) I tried to start it. Only cranked, but wouldn't start. Wiggled the wires to the MAP sensor, nothing. Crank sensor, nothing. TPS, nothing. Temp sensor, nothing. Reached down behind the alternator and A/C compressor to wiggle the wires to the ignition control module.....then she started right up! Ran fine for a while, turned it off, started back up, pulled her out of the garage and spun her around, put her back. Ran fine the whole time.

Then I wanted to see if I could replicate the problem to isolate the problem to the wire harness going to the ICM. Used a dowel rod and manipulated the harness and boom....engine cut out immediately. So, I am extremely pleased with what I will call progress for now. It could very well be the heavy gauge ground cable that bolts to the engine block, but I haven't had a chance to get in there and really check all the connections to the alternator and block. At least I have a starting point.

So again I say thank you DredNot! This tip got me going in the right direction again!
 

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I want to say thank you to DredNot for this bit of advice. I have not messed with my Jeep since June 2016 because the engine would just die for no reason. Sometimes it would start back up, others it wouldn't. Did this 12 times on a 20 minute drive home from a friend's house last year and that was the last time I drove it. I haven't had the time or the energy to try and figure out what was wrong until recently when I came on here looking for someone else with a similar problem. My battery was also dead, so after swapping in a new battery (free replacement from PepBoys, got it in just under the 3 year deadline!) I tried to start it. Only cranked, but wouldn't start. Wiggled the wires to the MAP sensor, nothing. Crank sensor, nothing. TPS, nothing. Temp sensor, nothing. Reached down behind the alternator and A/C compressor to wiggle the wires to the ignition control module.....then she started right up! Ran fine for a while, turned it off, started back up, pulled her out of the garage and spun her around, put her back. Ran fine the whole time.

Then I wanted to see if I could replicate the problem to isolate the problem to the wire harness going to the ICM. Used a dowel rod and manipulated the harness and boom....engine cut out immediately. So, I am extremely pleased with what I will call progress for now. It could very well be the heavy gauge ground cable that bolts to the engine block, but I haven't had a chance to get in there and really check all the connections to the alternator and block. At least I have a starting point.

So again I say thank you DredNot! This tip got me going in the right direction again!
I can't believe the last time I messed with my jeep was July. Finally made time to dig further two days ago. The culprit was a worn connector at the ignition module. Seems to be fixed now!
 
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