96 ZJ dying again! - Page 4 - JeepForum.com
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post #46 of 53 Old 02-06-2019, 09:08 PM Thread Starter
xtrattitude4u
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1996 ZJ 
 
Join Date: May 2013
Location: Vancouver
Posts: 89
There were still no codes stored in the PCM.
I followed the dirty dozen and cleaned the fuse box connections, alternator connections, and all the relay and fuse contacts, no dice.

Today I received a new Mopar crankshaft sensor so I installed it. Took her for a test drive for over an hour and there were no issues.

I'll need to give it more time to be sure, but it seems fixed. I tried viewing the 5v signal output of the original sensor with a oscilloscope but I couldn't get any clear reading.

While I was at it, I upgraded the batt ground cable and installed the military spec terminals.

The crank sensor was only 2 yrs old and was a Mopar. But the silicone was already separating from the lead wires, allowing moisture and who knows what into the sensor, likely shorting it out.

I may pull it out and cake the top in more silicone in attempt to make it last longer.

I guess they don't make them like they used to.







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post #47 of 53 Old 02-07-2019, 01:36 PM Thread Starter
xtrattitude4u
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1996 ZJ 
 
Join Date: May 2013
Location: Vancouver
Posts: 89
Well it died again.
It started up once enough for us to park it, then was back to crank no start.

This time it threw a code:

P0351- ignition coil primary / secondary circuit.

I had my wife try to crank it while I wiggled the PCM connectors first, nothing. Grab the harness and shook it around, nothing. Wiggled the main ignition wire around, nothing.

Grabbed a screwdriver and gave the coil a good tap on the side, boom it started right up.

So the brand new Delphi ignition coil I just purchased is bad.

:Facepalm:



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post #48 of 53 Old 02-07-2019, 10:38 PM
ZeeJay1997
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Quote:
Originally Posted by xtrattitude4u View Post
So the brand new Delphi ignition coil I just purchased is bad.

The two pin connector at the coil. Take note of which wire goes where. Slide the red tab out, open the connector, and remove the sockets and wires from the connector. Do a fit test on the pins, one at a time. They are probably loose. Use a small pair of pliers to VERY slightly elongate the bore of the socket. Easy does it. Fit test again. Repeat until the sockets have enough friction to hold themselves firmly.


Did this to mine about 100k ago and no more coil codes.
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post #49 of 53 Old 02-08-2019, 08:54 AM Thread Starter
xtrattitude4u
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Join Date: May 2013
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Quote:
Originally Posted by ZeeJay1997 View Post
The two pin connector at the coil. Take note of which wire goes where. Slide the red tab out, open the connector, and remove the sockets and wires from the connector. Do a fit test on the pins, one at a time. They are probably loose. Use a small pair of pliers to VERY slightly elongate the bore of the socket. Easy does it. Fit test again. Repeat until the sockets have enough friction to hold themselves firmly.


Did this to mine about 100k ago and no more coil codes.
Thanks Zeejay.

I'll be doing this.
I swapped the coil again last night but it's still doing the same thing.

The funny thing is, I can't get it to die by wiggling that connector. I also can't get it to start up again when I wiggle that connector during crank no start.

It seems only tapping on the side of the coil will spring it back to life. I can't get it to die by tapping on it either, only get it to fire up and run for awhile after tapping on it.

I forced the guy at the parts store to tap on the coil I returned on their test bench.


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post #50 of 53 Old 02-08-2019, 09:04 AM
ZeeJay1997
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Quote:
Originally Posted by xtrattitude4u View Post
The funny thing is, I can't get it to die by wiggling that connector. I also can't get it to start up again when I wiggle that connector during crank no start.
The socket makes contact with the pin with hairlike, spring loaded wires. Once they get weak and carboned, they are peculiar about passing current. While you have it apart, spray some contact cleaner inside the sockets and blow them out with compressed air.


You may have to replace the connector.


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post #51 of 53 Old 02-08-2019, 09:27 AM
ZeeJay1997
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Oh yeah, it's easier if you have the coil removed when you fit check the sockets.


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post #52 of 53 Old 02-10-2019, 10:31 PM Thread Starter
xtrattitude4u
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Join Date: May 2013
Location: Vancouver
Posts: 89
Thanks for the suggestion ZeeJay!
I think I figured this out.

I took the connector apart and test fitted the sockets on the original coil and they held on great on the right pin, ok on the left.

I then took the new aftermarket coil out and the fit was horrible. Both sockets are so loose on the pins they basically just fall off.

So the pins on the new coil are slightly smaller in diameter than the original.

The left pin on the original coil was slightly loose so I ovaled the socket slightly to get a better fit.

Some more test drives are needed to be sure, but I think this is the final issue. If the coil gives me any trouble, I'll get a Mopar one. The only reason I replaced it was the resistance was lower than spec, but maybe that's not a problem.

Another lesson learned the hard way about aftermarket parts.

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post #53 of 53 Old 02-17-2019, 04:45 PM Thread Starter
xtrattitude4u
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1996 ZJ 
 
Join Date: May 2013
Location: Vancouver
Posts: 89
The Jeep's been running fine since I switched back to the old coil.

Big thanks to ZeeJay and Goldwing for the suggestions.

On a side note, the dirty dozen is an amazing thread, thanks for putting that together ZeeJay.
I didn't know about it until you mentioned it.
Need to search better I guess.

So my initial problem was the crank sensor, although it was a new MOPAR and only 2 yrs old.
Not sure why the original lasted 20 years and this one lasted 2.

It tested good every time I tested it, so there was no hint of any issue until I replaced it. The CEL never came on, even after cranking with no start.
Last time it failed, the PCM threw an ignition code once it was in crank no start.

The PCM was also on it's way out, so I'm glad I took care of that. I'm not sure it was causing any dying yet, but it probably was going to soon.

All the grounds are now pristine as well.

I created problem #2 by putting in a coil with pins that we're too small. So don't buy Delphi brand coils, because 2 of them had that problem.

With all the cranking we did the 1year old battery probably needs to be done now too.

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