96-98 PCM repair procedure W/Pictures - Page 3 - JeepForum.com

 1Likes
Reply
 
LinkBack Thread Tools
post #31 of 203 Old 12-20-2011, 11:04 PM Thread Starter
JS97ZJ
Registered User
2004 WJ 
 
Join Date: Dec 2009
Location: Dingmans Ferry
Posts: 2,279
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.

JS97ZJ is offline  
Sponsored Links
Advertisement
 
post #32 of 203 Old 12-20-2011, 11:20 PM Thread Starter
JS97ZJ
Registered User
2004 WJ 
 
Join Date: Dec 2009
Location: Dingmans Ferry
Posts: 2,279
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?...
JS97ZJ is offline  
post #33 of 203 Old 12-20-2011, 11:25 PM
MeanGreenZJ
Web Wheeler
 
Join Date: Apr 2011
Location: Mean Street in a desperate part of town
Posts: 1,710
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?...
MeanGreenZJ is offline  
post #34 of 203 Old 12-20-2011, 11:26 PM
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Posts: 8,612
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.
ZeeJay1997 is offline  
post #35 of 203 Old 12-20-2011, 11:29 PM Thread Starter
JS97ZJ
Registered User
2004 WJ 
 
Join Date: Dec 2009
Location: Dingmans Ferry
Posts: 2,279
I must have missed a section in the FSM.
JS97ZJ is offline  
post #36 of 203 Old 02-08-2012, 04:33 PM
henrygeorge
Registered User
1999 WJ 
 
Join Date: Nov 2011
Location: marietta
Posts: 79
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.
henrygeorge is offline  
post #37 of 203 Old 02-08-2012, 11:05 PM Thread Starter
JS97ZJ
Registered User
2004 WJ 
 
Join Date: Dec 2009
Location: Dingmans Ferry
Posts: 2,279
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.
JS97ZJ is offline  
post #38 of 203 Old 02-21-2012, 11:29 AM
gt88
Registered User
1996 ZJ 
 
Join Date: Mar 2006
Location: Bay area
Posts: 13
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.
gt88 is offline  
post #39 of 203 Old 04-27-2012, 09:29 PM
goatmurray
Registered User
1997 ZJ 
 
Join Date: Apr 2012
Location: Wenatchee
Posts: 41
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.
goatmurray is offline  
post #40 of 203 Old 04-27-2012, 10:32 PM Thread Starter
JS97ZJ
Registered User
2004 WJ 
 
Join Date: Dec 2009
Location: Dingmans Ferry
Posts: 2,279
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.
JS97ZJ is offline  
post #41 of 203 Old 04-28-2012, 11:32 AM
goatmurray
Registered User
1997 ZJ 
 
Join Date: Apr 2012
Location: Wenatchee
Posts: 41
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.


goatmurray is offline  
post #42 of 203 Old 04-28-2012, 11:35 AM
goatmurray
Registered User
1997 ZJ 
 
Join Date: Apr 2012
Location: Wenatchee
Posts: 41
Quote:
Originally Posted by goatmurray View Post
...yank that thing out of the housing by the gang connector!
If ya know what I mean.
goatmurray is offline  
post #43 of 203 Old 04-28-2012, 10:05 PM Thread Starter
JS97ZJ
Registered User
2004 WJ 
 
Join Date: Dec 2009
Location: Dingmans Ferry
Posts: 2,279
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............
JS97ZJ is offline  
post #44 of 203 Old 05-08-2012, 04:51 PM
goatmurray
Registered User
1997 ZJ 
 
Join Date: Apr 2012
Location: Wenatchee
Posts: 41
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.
goatmurray is offline  
post #45 of 203 Old 05-15-2012, 09:48 PM
AAA
Registered User
1997 ZJ 
 
Join Date: Apr 2010
Location: Los Angeles
Posts: 115
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.
AAA is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
CRD Oil Change Procedure rhusak WK Grand Cherokee & XK Commander Forum 5 08-28-2010 07:59 PM
procedure from 4hi to 4lo 69speed ZJ Grand Cherokee Forum 3 10-08-2007 09:33 PM
CAT Removal Procedure kdavis ZJ Grand Cherokee Forum 24 09-24-2007 06:51 AM
Connecticut Repair Shops Capable of Axle Repair? dogbait ZJ Grand Cherokee Forum 2 02-12-2007 06:28 PM
Cleaning procedure Endurancevm ZJ Grand Cherokee Forum 5 03-18-2006 05:08 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome