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99 PCM replace/update

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Old Jun 18, 2019 | 05:45 AM
  #76  
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I mean, you could have this, too:



https://www.jeepforum.com/forum/f13/...ptoms-1405626/

The center could spin in worse case scenario.
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Old Jun 18, 2019 | 05:57 AM
  #77  
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Originally Posted by Dave51
And the CPS is properly positioned over the windows?



I wish I had a better picture of the chain, I tried documenting everything with this.
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Old Jun 18, 2019 | 06:01 AM
  #78  
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Originally Posted by Dave51
A PO could have messed it up, but given the history, I imagine not. At any rate, the position of the windows is critical, and if it wasn't checked it needs to be.
I'm happy to check, but what needs to be done for this, there is no play in the sensor bolts or bell mounts?
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Old Jun 18, 2019 | 06:08 AM
  #79  
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Pull the inspection plate on the bell housing and check the condition of the flexplate. Has the P1391 been there since you had everything apart?
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Old Jun 18, 2019 | 06:23 AM
  #80  
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Originally Posted by Dave51
Pull the inspection plate on the bell housing and check the condition of the flexplate. Has the P1391 been there since you had everything apart?
It started before and exists still. I just had the flex plate off to recheck torque converter bolts, I'll pop it off again anyway and see what can be seen.
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Old Jun 18, 2019 | 07:07 AM
  #81  
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Originally Posted by 4x4jeepmanthing
Yes, a few months back I swapped engines.
So the 1391 was happening with your old engine?
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Old Jun 18, 2019 | 01:24 PM
  #82  
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Originally Posted by Dave51
So the 1391 was happening with your old engine?
Correct, and new
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Old Jun 19, 2019 | 05:21 AM
  #83  
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Originally Posted by Dave51
Omigod!! This conspiracy is worse than I thought! In the 1997 FSM, even the Chrysler people think there's a TCM in there!! It's the grassy knoll all over again!
Allright. I see this is about xj, not zj. ZJ did not have the tcm, as the zj and xj have completely different transmissions. My bad.
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Old Jun 19, 2019 | 05:33 AM
  #84  
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No sweat,


pulled the pan, front had oil seeping, ugh I detest rework. How much play in a chain is normal, it has some, but nothing crazy I don't think. Bought rosin flux for making the test leads as AWG suggested. Do you think a t pin will except solder?

Didn't get around to pulling the distributor cap and checking the chain degree, it was late and I'm beat tired.

Last edited by 4x4jeepmanthing; Jun 22, 2019 at 07:23 PM.
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Old Jun 19, 2019 | 06:03 AM
  #85  
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Originally Posted by 4x4jeepmanthing
How much play in a chain is normal...
"If the timing chain deflects more than 12.7 mm (1/2 inch) replace it."
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Old Jun 19, 2019 | 06:35 AM
  #86  
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Originally Posted by 4x4jeepmanthing

Bough riding flux for making the test leads as AWG suggested. Do you think a t pin will except solder?

Didn't get around to pulling the distributor cap and checking the chain degree, it was late and I'm beat tired.
you dont really need solder, just a good twist of wire (why thin 5amp is good) and tape it for insulation..doesnt have to be fancy, this is temp test lead

use small safety pins about 1"long

I would really want to eliminate excessive chain slack..that is what the warning code is saying..or an intermitent loss of signal

hopefully ur close
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Old Jun 19, 2019 | 08:09 PM
  #87  
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Originally Posted by 4x4jeepmanthing

Listen closely and you can hear the Pilsbury Dough Boy laughing lol.
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Old Jun 19, 2019 | 11:43 PM
  #88  
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Originally Posted by fb97xj1
Listen closely and you can hear the Pilsbury Dough Boy laughing lol.
Lol,


I tried the donor pcm, that didn't work so I called the shop back that did the diagnostic, they are going to give me my money back. Really nice folks, but he didn't even know where to point me because of how well everything looked. They use a Snap on scope. He was happy to take another look, but he also said he believed he wouldn't find anything new if they did. He would like to know if I figure it out.

Anyhow, 7 degree on the chain. I did this twice to be sure. I need to verify that tolerance.
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Old Jun 20, 2019 | 01:59 AM
  #89  
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Originally Posted by 4x4jeepmanthing
I tried the donor pcm, that didn't work so I called the shop back that did the diagnostic, they are going to give me my money back. Really nice folks, but he didn't even know where to point me because of how well everything looked. They use a Snap on scope. He was happy to take another look, but he also said he believed he wouldn't find anything new if they did. He would like to know if I figure it out.

Anyhow, 7 degree on the chain. I did this twice to be sure. I need to verify that tolerance.
I wouldnt accept his money back, but thank him for his time so far...

7 degrees, did you say earlier that was right on the max ?...is that 7* of slack ?

I dont have much experience with chains wearing & stretching, but it does happen on engines with high mileage, set a code on models with electronics

there should be be other people that know all about Jeep timing chains, the XJ has a pretty robust looking arrangement..the GM Alloytec not so much
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Old Jun 20, 2019 | 06:08 AM
  #90  
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Originally Posted by Dave51
So the 1391 was happening with your old engine?
Originally Posted by 4x4jeepmanthing
Correct, and new
So from what I can gather, the P1391 has occurred on 2 entirely different engines (except for the flexplate)? You put new sensors on the old engine, but reused them on the new engine? What year is the replacement engine?
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