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Unread 12-21-2011, 12:04 AM   #31
JS97ZJ
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Quote:
Originally Posted by MeanGreenZJ View Post
Below is a PDF of the Chrysler drive cycle that lists the conditions that must be met before the PCM is ready with all monitors active after disconnecting the battery.

http://img.neons.org/archives/chrysler_drive_cycle.pdf
Thanks for the link.

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Unread 12-21-2011, 12:20 AM   #32
JS97ZJ
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Quote:
Originally Posted by ZeeJay1997 View Post
Catalyst Monitor Drive Trace
Pre-Conditioning Requirements:
- MIL must be off.
- No DTCs present.
- Fuel level is between 15% and 85% full.
- ECT above 70º F.
- Engine must have run at least 90 seconds
- Engine between 1,350 & 1,900 rpm.

This is interesting because if the fuel is below about 1/4 tank when it fails, the fuel gauge pegs to zero. It also occurs only in the RPM range mentioned above.

So how does a catalyst monitor kill a PCM? (this is a rhetorical question)
Zee, Where on earth do you get all your info from?...
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Unread 12-21-2011, 12:25 AM   #33
MeanGreenZJ
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It's all in the PDF link....

Quote:
Originally Posted by JS97ZJ View Post
Zee, Where on earth do you get all your info from?...
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Unread 12-21-2011, 12:26 AM   #34
ZeeJay1997
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Quote:
Originally Posted by JS97ZJ View Post
Zee, Where on earth do you get all your info from?...
From the FSM and the link MeanGreen posted.
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Unread 12-21-2011, 12:29 AM   #35
JS97ZJ
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I must have missed a section in the FSM.
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Unread 02-08-2012, 05:33 PM   #36
henrygeorge
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what i've deduced from this write-up is that one can use a metal ty-wrap to hold the computer and connectors snug to minimize shorting until new connectors are soldered to the wire harness and/or the pcm is ordered and replaced.

i did notice on a replacement pcm that the rebuilder just cut into the back of the computer, filling in the hole with potting compound, to check the integrity of the solder joints on the back of the pcm while ignoring the connections on the top of the mother board as an unlikely failure point, with going in through the front being the source of a new failure point.
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Unread 02-09-2012, 12:05 AM   #37
JS97ZJ
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Quote:
Originally Posted by henrygeorge View Post
what i've deduced from this write-up is that one can use a metal ty-wrap to hold the computer and connectors snug to minimize shorting until new connectors are soldered to the wire harness and/or the pcm is ordered and replaced.

i did notice on a replacement pcm that the rebuilder just cut into the back of the computer, filling in the hole with potting compound, to check the integrity of the solder joints on the back of the pcm while ignoring the connections on the top of the mother board as an unlikely failure point, with going in through the front being the source of a new failure point.
To clear up your confusion with your deduction, the ty-wrap/pipe clamp or whatever that is being used to secure the connectors to the PCM, is only a temporary fix and is only a way of telling that there is a bad connection (not a short) in the soldered connections that are making contact between the female portion of the connector and the PCM circuit board. The wire harness portion of the connector (male connector), is not the source of the problem. It also seems that the cause of the intermittent shutting off, is being caused by an internal lost off of power from the 5v power regulator, that the PCM operates on. One of those 96 pins on the circuit board has the bad soldering connection that is causing the problem.

By securing the connectors to the PCM with the ty-wraps is only forcing the female part of the connector to make better contact with the PCM's main board.

The cut out portion of ZeeJay's PCM, was an attempted repair performed by a company that does repairs on automotive computers. They cut out the back of the unit to gain access to the back of the PCM in order to re flow the pins. They ended up soldering the wrong pins and almost completely destroying the mother board.
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Unread 02-21-2012, 12:29 PM   #38
gt88
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Possible reading comprehension issue here, but...

Hi guys, havent been back here in a long while, but thank the guy upstairs that you've been busy! The wife's daily 96 has been doing the stall dance for about a year now, off and on, and of course its cold out so here we go again.

So, one question, it seems the stalling issue is 4.0 specific? I did read through the "Infamous stalling" thread (War and Peace meets Jeep?) and I didnt see any of the v8 guys getting this symptom. Did I miss it?

Also, if this is a 6 only situation, has anybody split open a v8 case to look for differences? Or, not being 100% "up" on Jeep software/flashing, can a v8 control unit be reprogrammed for a 6 cylinder application?

To sum it up, thanks for what I professionaly know was a lot of hard work here-

Also, to keep it short, I'll run my 2 cents input on this subject in the other thread.
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Unread 04-27-2012, 10:29 PM   #39
goatmurray
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I tried doing this, but I can't get the MB out of the housing. I tried a 1,000 degree heat gun and a propane torch to no avail. All it does is soften up the compound a little bit. What can I do?

My only car is now inoperable. I need help ASAP.
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Unread 04-27-2012, 11:32 PM   #40
JS97ZJ
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Quote:
Originally Posted by goatmurray View Post
I tried doing this, but I can't get the MB out of the housing. I tried a 1,000 degree heat gun and a propane torch to no avail. All it does is soften up the compound a little bit. What can I do?

My only car is now inoperable. I need help ASAP.
Forget the heat gun on this repair. Did you make sure that you loosened the sides of the compound in the corners and under the metal strips with a knife down to the bottom of the case?

The case will have to be held in a vise, and gently pull the MB out with a pair of channel locks by the MB connectors.

Grab it only by the strongest part. (Bridged section between the connector)

EVENLY HEAT THE ENTIRE BACK with a torch. I used a map gas torch to make it heat up quicker but propane will be ok.

It's going to take quite a bit of heat to get that sucker out. It will smoke and boil some of the potting compound out from around the sides. Be careful you don't get any of that melted stuff on you. It's not going to hurt the MB. Let it cool completely once it's out.
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Unread 04-28-2012, 12:32 PM   #41
goatmurray
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Thanks js97sj!
I had previously underestimated the integrity of that potting compound.
Went back at it with the propane torch blastin'... Did the trick.
Still scared the poop out of me trying to yank that thing out of the housing by the gang connector!

It's all back together now and I'm going to take it through a drive cycle today and see how it does.
You don't know how relieved I was to hear that thing start up last night after I put it back in.


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Unread 04-28-2012, 12:35 PM   #42
goatmurray
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Quote:
Originally Posted by goatmurray View Post
...yank that thing out of the housing by the gang connector!
If ya know what I mean.
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Unread 04-28-2012, 11:05 PM   #43
JS97ZJ
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It's a little time consuming, but it's worth it.
I don't think that most of these repair companies go into removing the MB in order to properly reflow these connections due to the time restrictions they probably have so they can come out making a profit.

Keep us advised............
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Unread 05-08-2012, 05:51 PM   #44
goatmurray
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ZJ's been doing great.
Now it runs like a champ no matter what.
Held up through heat, cold, wet, dusty, bumpy, shaky conditions so far- no stalling or stumbling or anything.
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Unread 05-15-2012, 10:48 PM   #45
AAA
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I have been having the Jeep stalling issue since June 2011, and now it's May 2012. I tested all the sensors and everything tested good. I researched online, drove around with an OBD II scanner connected to see if I could figure it out, and tons of other things. Nothing helped until I did the zip tie trick. It still stalled, but it changed from stalling after 30 minutes of driving, to stalling about 2 minutes after starting the Jeep. Since I read on this write-up that if the zip tie either fixes or changes the stalling pattern, then I decided to give the soldering trick a try. Well, it's been 9 days now and it hasn't stalled since doing this repair. I think I'll wait a few more weeks before sealing up the PCM for good, but so far so good. Thanks a million for doing this write-up with the pics. It really helped me to know what to expect. If you are having the stalling issue and the zip tie helps, do yourself a favor and take the time to re-solder the pins on the PCM.
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