My '97 JGC has hit an iceburg - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > My '97 JGC has hit an iceburg

Component speaker deal for your dash - NalinMFGIntroducing MONSTALINER™ UV Permanent DIY Roll On Bed LineSteering and more from Ruffstuff!

Reply
Unread 05-12-2013, 05:27 PM   #1
chalkboard
Registered User
1997 ZJ 
 
Join Date: May 2013
Location: SoCal, CA
Posts: 54
My '97 JGC has hit an iceburg

I am in my fifties and this is my first post on this great forum. I know how to use a wrench, but current electrical systems are more complex than I have worked with in the past. Unfortunately, I don't think this ZJ can be saved. I have owned it for 10 years and it has 148k on the solid six.

History: Stalling started 4 or 5 years ago. Once every few months in the beginning, then progressed to every few weeks about 3 years ago. Finally, it became much worse including dying at about every light and random stalls at any speed, any temperature, and any weather. I took it to the dealer: Their diagnosis was it needs a new pcm and harness plug. The cost was 2500.00 and no guarantees.

I then went for a second opinion at a reputable shop down the street: Their diagnosis was the harness plug is good, just needs a pcm,,so I let them do it, if they would guarantee the plug. After the repairs it ran better than it ever had for a few months, then the stalling returned. I took it back and they admitted the plug was bad and they replaced the harness at no expense. It then runs decent for a month or two before returning to its stalling norm. The shop assures me all the sensors are good and that there is nothing more they can do.

Current: It will stall under any circumstance, but always restarts easily. There are no check engine lights. It always gets me from point A to B, but this stalling is unsafe and I need to figure it out.

I have read the dirty dozen and have spent hours researching this forum. I am going to start with the grounds and work my way back to the pcm, but my hunch is that the old harness knocked out the new mopar pcm the shop installed. Any thoughts? I'm also shopping for a different JGC, are there any years that don't have this stalling issue?

Sorry for the long post.

chalkboard is offline   Reply With Quote
Unread 05-12-2013, 07:14 PM   #2
Oldfrog
Web Wheeler
1997 ZJ 
 
Join Date: Feb 2008
Location: Louisiana/Texas
Posts: 3,629
Welcome to the forum.

My 97 has had the same issues from time to time. I'm on my 4th PCM. The latest is another Cardone brand PCM....and it's doing it again, once in a while. I bought some dental style picks from Harbor Freight today on my way back from the lake, ( yes, we slaughtered the bass and bream on Toledo Bend this weekend...yay !).... to attempt the most recent "fix", which is to close up the connectors on the harness as described in a thread here. " The REAL fix" is in the title...I believe.

But I dont think that's it, truthfully. 'Going to try it anyway, just to eliminate it as a cause.
I think it's more than that. I think there are other grounding points that become loose. One, as I recall reading about, is under the dash on the firewall near the glove box. ( dont quote me on that one) The A/C unit gets it wet and it rusts the grounding point. We'll see.

Another theory:
I've noticed that when idling, in park, I have a habit of hitting my window buttons, one by one, to make sure the windows are all up....well....the engine RPMs have dropped at times when I do that, which indicates a low current ( amperage) condition in the charging system. This could also indicate a bad ground somewhere....or a window circuit that's pulling too much current w/o tripping fuse or breaker. I'm on my second replacement alternator and my 4th (?) battery since I bought the vehicle new. Are the aftermarket alternators weak or faulty ? What about the cheap batteries we buy now. ( at $100+ today) I have no idea.....but an upgrade is in my plans.

Or is it just the badly soldered boards on many of the PCMs? There are people on here who have had to try 4 different PCMs before they got a good one.

-What about aftermarket O2 sensors? Are they frying the PCMs?
-Clogged cats? Will they cause the ASD relay to trip or screw up the PCM ?
I'm on the second cat now...so we'll see if Meineke honors that warranty this week, because I'm going to see them.

How about low vacuum? I mean....geez...I have 238K on the original engine. Maybe the map sensor and the rest of the BS they put on these engines now cause the PCM to act stupid or lazy, due to low engine vacuum. I have no idea.

I had it fixed for 11 months with a new PCM that was zip tied. Then it ran ok for another 6 months on the replacement. Now the replacement PCM ( Cardone brand, under warranty) is screwing up, mainly on high humidity days, or when the temps drop below 55 degrees at night.
I still have my original PCM and time permitting, I'll get the potting compound out of it with a torch and re-solder the pins, replace any electrolytics in it, and try again. But if there is another unresolved issue somewhere on the Jeep, it may all be for naught until I find it.

I also wonder if oil leaking from the valve cover and/or rear main seal, somehow screws with the crank sensor readings, assuming the oil ever hits the flywheel.

Who knows? I'm still searching for the ultimate "fix", and hitting each of the obvious ones, as time allows. If it was just about money, I'd have it cured already, because money really isnt the main issue in my particular case. I just want it fixed correctly.
__________________
Cajun Recipes and Fishing tips

Words of wisdom, Posted by Zeejay:
"..it's not air, it is the opposite of air... suckage so to speak."

Stalling? Work through Zeejay's list
Oldfrog is online now   Reply With Quote
Unread 05-12-2013, 07:21 PM   #3
Oldfrog
Web Wheeler
1997 ZJ 
 
Join Date: Feb 2008
Location: Louisiana/Texas
Posts: 3,629
Did someone actually sell you a new harness plug?

Here's some other info I have accumulated:
"NUMBER: 25-003-01
GROUP: Emissions
DATE: Feb. 23, 2001

Google it, as we are not allowed to publish it.

I'm also looking for the Jeep harness plug repair kit info...and will post it when I find it.
__________________
Cajun Recipes and Fishing tips

Words of wisdom, Posted by Zeejay:
"..it's not air, it is the opposite of air... suckage so to speak."

Stalling? Work through Zeejay's list
Oldfrog is online now   Reply With Quote
Unread 05-12-2013, 07:47 PM   #4
chalkboard
Registered User
1997 ZJ 
 
Join Date: May 2013
Location: SoCal, CA
Posts: 54
Quote:
Originally Posted by Oldfrog View Post
Welcome to the forum.

My 97 has had the same issues from time to time. I'm on my 4th PCM. The latest is another Cardone brand PCM....and it's doing it again, once in a while. I bought some dental style picks from Harbor Freight today on my way back from the lake, ( yes, we slaughtered the bass and bream on Toledo Bend this weekend...yay !).... to attempt the most recent "fix", which is to close up the connectors on the harness as described in a thread here. " The REAL fix" is in the title...I believe.

But I dont think that's it, truthfully. 'Going to try it anyway, just to eliminate it as a cause.
I think it's more than that. I think there are other grounding points that become loose. One, as I recall reading about, is under the dash on the firewall near the glove box. ( dont quote me on that one) The A/C unit gets it wet and it rusts the grounding point. We'll see.

Another theory:
I've noticed that when idling, in park, I have a habit of hitting my window buttons, one by one, to make sure the windows are all up....well....the engine RPMs have dropped at times when I do that, which indicates a low current ( amperage) condition in the charging system. This could also indicate a bad ground somewhere....or a window circuit that's pulling too much current w/o tripping fuse or breaker. I'm on my second replacement alternator and my 4th (?) battery since I bought the vehicle new. Are the aftermarket alternators weak or faulty ? What about the cheap batteries we buy now. ( at $100+ today) I have no idea.....but an upgrade is in my plans.

Or is it just the badly soldered boards on many of the PCMs? There are people on here who have had to try 4 different PCMs before they got a good one.

-What about aftermarket O2 sensors? Are they frying the PCMs?
-Clogged cats? Will they cause the ASD relay to trip or screw up the PCM ?
I'm on the second cat now...so we'll see if Meineke honors that warranty this week, because I'm going to see them.

How about low vacuum? I mean....geez...I have 238K on the original engine. Maybe the map sensor and the rest of the BS they put on these engines now cause the PCM to act stupid or lazy, due to low engine vacuum. I have no idea.

I had it fixed for 11 months with a new PCM that was zip tied. Then it ran ok for another 6 months on the replacement. Now the replacement PCM ( Cardone brand, under warranty) is screwing up, mainly on high humidity days, or when the temps drop below 55 degrees at night.
I still have my original PCM and time permitting, I'll get the potting compound out of it with a torch and re-solder the pins, replace any electrolytics in it, and try again. But if there is another unresolved issue somewhere on the Jeep, it may all be for naught until I find it.

I also wonder if oil leaking from the valve cover and/or rear main seal, somehow screws with the crank sensor readings, assuming the oil ever hits the flywheel.

Who knows? I'm still searching for the ultimate "fix", and hitting each of the obvious ones, as time allows. If it was just about money, I'd have it cured already, because money really isnt the main issue in my particular case. I just want it fixed correctly.

Thank you for the welcome!!

I am going to do all the free stuff first, including the pin fix you mention. FYI,,Those picks can be purchased at the local drugstore for very little. I would be interested to learn how it works for you.

The fact that mine ran perfect with a new Dealer PCM tells me it can be fixed and that I just have to find the short that keeps killing my PCM.
chalkboard is offline   Reply With Quote
Unread 05-12-2013, 07:56 PM   #5
Oldfrog
Web Wheeler
1997 ZJ 
 
Join Date: Feb 2008
Location: Louisiana/Texas
Posts: 3,629
http://http--www.dodgeram.info/tsb/1997/08-01-97.htm
__________________
Cajun Recipes and Fishing tips

Words of wisdom, Posted by Zeejay:
"..it's not air, it is the opposite of air... suckage so to speak."

Stalling? Work through Zeejay's list
Oldfrog is online now   Reply With Quote
Unread 05-12-2013, 08:11 PM   #6
chalkboard
Registered User
1997 ZJ 
 
Join Date: May 2013
Location: SoCal, CA
Posts: 54
Quote:
Originally Posted by Oldfrog View Post
Did someone actually sell you a new harness plug?

Here's some other info I have accumulated:
"NUMBER: 25-003-01
GROUP: Emissions
DATE: Feb. 23, 2001

Google it, as we are not allowed to publish it.

I'm also looking for the Jeep harness plug repair kit info...and will post it when I find it.
Hi Frog,

The Jeep dealer stocks a plug with a pigtail for that year. As I am sure you are aware, they no longer stock the whole harness.

In my case, the technician at the dealer was going to cut off the old plug and splice/solder the new one on. Aside from the expense, I doubted he could really do that successfully, and I looked for other solutions.

The local shop I mentioned, honored their guarantee of the plug's condition and replaced the whole engine harness. However it was one from the salvage.
chalkboard is offline   Reply With Quote
Unread 05-13-2013, 06:01 AM   #7
KoreaZJ
Registered User
1994 ZJ 
 
Join Date: Aug 2011
Location: GANGNAM STYLE
Posts: 2,666
Quote:
Originally Posted by Oldfrog View Post
...Another theory:
I've noticed that when idling, in park, I have a habit of hitting my window buttons, one by one, to make sure the windows are all up....well....the engine RPMs have dropped at times when I do that, which indicates a low current ( amperage) condition in the charging system. This could also indicate a bad ground somewhere....or a window circuit that's pulling too much current w/o tripping fuse or breaker...
Mine has always done this since new. A stalled window motor draws lots of current, but not enough to trip the 30 amp circuit breaker.
KoreaZJ is offline   Reply With Quote
Unread 05-17-2013, 05:27 PM   #8
chalkboard
Registered User
1997 ZJ 
 
Join Date: May 2013
Location: SoCal, CA
Posts: 54
Update

Update: I decided to follow my hunch and go back to the local shop to talk to them about getting another PCM since I felt the engine harness plug had knocked out the Dealer PCM they installed. I also asked them what happened to my factory security system which seems to be missing or non-functioning. Their response was unexpected, "Don't ever bring that Jeep back again." lol.

I have since checked the engine grounds, but I live in SoCal so corrosion is not really an issue here. However, I did find a loose fender-to-negative battery terminal ground and fixed that. It made no difference in my stalling.

I then decided to clean the harness and PCM connections. First I used canned air to clean both sides of the connections. I then used Deoxit to clean and lubricate everything both male and female.. Finally, though really tedious, I put a tiny pinhead size dot of dialectic grease on each female connection pin. After doing this 30 minute job, I have not had a single stall.

I can't believe this fixed it, but time will tell. I would sure like to know what happened to my security system.

I will update again in a few days.
chalkboard is offline   Reply With Quote
Unread 05-17-2013, 05:52 PM   #9
Mickey_D
Registered User
1997 ZJ 
 
Join Date: Aug 2008
Location: 40° 3'42.36"N 112° 2'16.73"W, Utah
Posts: 6,709
The security system probably wasn't programmed in to the PCM before it shipped out.

Do you have the auto headlight function? Does it still work?

Does yours auto lock the doors when you hit 15mph?


There are a considerable amount of options that are controlled/included in the PCM that have to be enabled/changed by someone with a DRBIII scan tool (generally only dealerships can afford these, and they charge A LOT to use them). Just as an instance, the only way to program the key fob remotes on 96-98 is with a DRBIII...
__________________
1997 ZJ 5.2 Orvis, Baby!
1953 Willys M100 trailer Tagalong
________________
[_][][][][][][][][_]


Mickey_D is offline   Reply With Quote
Unread 05-17-2013, 10:59 PM   #10
chalkboard
Registered User
1997 ZJ 
 
Join Date: May 2013
Location: SoCal, CA
Posts: 54
[QUOTE=Mickey_D;15447119]The security system probably wasn't programmed in to the PCM before it shipped out.

Do you have the auto headlight function? Does it still work?

Does yours auto lock the doors when you hit 15mph?


Hi Mickey,

Thank you for your insight.

I don't have the auto-headlights, or the auto locks at 15 mph.

Also, I believe you confirmed my concerns about the PCM lacking what I need regarding the security system. I learned before having my Jeep thrown out of the local shop that they had switched the very expensive, properly programmed PCM from the dealer with another one (I think from the same salvage as the harness) in an effort to fix the whole thing. Anyway I am on my own now. Next, I am going to find a cheap FSM so I can check the plumbing of the engine harness they installed. Then, I'll try to figure out what to do about my PCM.

I don't believe the stalling is gone yet, but it hasn't even thought about stalling since cleaning the PCM connectors.
chalkboard is offline   Reply With Quote
Unread 05-19-2013, 12:41 AM   #11
Oldfrog
Web Wheeler
1997 ZJ 
 
Join Date: Feb 2008
Location: Louisiana/Texas
Posts: 3,629
I hope it's fixed, but dont get your hopes up, my friend. Many of us have been there...more than once. I dont call it "fixed" until it runs without a hiccup for 200+ miles....and some of that has to occur on a rainy or cold day to make a believer out of me.

I have several ideas about this ongoing issue which I'm trying, one at a time. If one ( besides replacing yet another PCM) happens to work, I'll be sure to post it.
__________________
Cajun Recipes and Fishing tips

Words of wisdom, Posted by Zeejay:
"..it's not air, it is the opposite of air... suckage so to speak."

Stalling? Work through Zeejay's list
Oldfrog is online now   Reply With Quote
Unread 05-20-2013, 07:06 AM   #12
chalkboard
Registered User
1997 ZJ 
 
Join Date: May 2013
Location: SoCal, CA
Posts: 54
For completeness

I hope it's fixed, but dont get your hopes up, my friend. Many of us have been there...more than once. I dont call it "fixed" until it runs without a hiccup for 200+ miles....and some of that has to occur on a rainy or cold day to make a believer out of me.

I have several ideas about this ongoing issue which I'm trying, one at a time. If one ( besides replacing yet another PCM) happens to work, I'll be sure to post it.[/QUOTE]

Hi Frog,

I probably shouldn't have used the word fixed. But it is running fine for now. I have made a few drives that would have guaranteed a stall or two and I got nothing.

It looks like you have been living with this as long, or longer than I have. I, too, usually try to fix only one thing at a time, but this time, and I didn't mention it earlier, I had to replace a 5 year old Diehard simultaneously. I had cleaned the PCM connections in the evening and then couldn't start it the next morning for the first test drive. So, I jumped it and drove it (no stalls btw) to Sears. They tested it and it wouldn't even make 6 volts under load. Could replacing the battery have an effect? I didn't think so. Back in the day, it would have made no difference, but then cars didn't die at 70 on the freeway either, or if they did, we definitely knew why.

I reread one of your earlier posts. I don't have a problem with my power windows as you do. You mentioned your battery strength, well mine didn't have any, but I don't see how that could make a difference.
__________________
1997 ZJ Laredo Rwd/4.0/150k
chalkboard is offline   Reply With Quote
Unread 05-25-2013, 11:21 AM   #13
chalkboard
Registered User
1997 ZJ 
 
Join Date: May 2013
Location: SoCal, CA
Posts: 54
Update

UPDATE: It has now been more than a week of mixed city and freeway driving and I have not experienced a single stall since cleaning and lubricating the PCM connections. I had mentioned, I was going to try and repair the female pin connections using a dental pick as discussed elsewhere in this forum. But with a modest understanding of probability, I seriously doubted I could fix that many without screwing up at least one of them. So I tried the cleaning/lubricating first.

If the Jeep keeps this up, I may treat it to a full detail, new rotors and shoes on the front, transmission cooling lines and service, repair the headlight switch and more.

I'll update again in a couple of weeks
__________________
1997 ZJ Laredo Rwd/4.0/150k
chalkboard is offline   Reply With Quote
Unread 05-25-2013, 02:07 PM   #14
Oldfrog
Web Wheeler
1997 ZJ 
 
Join Date: Feb 2008
Location: Louisiana/Texas
Posts: 3,629
Dont go spoiling that ZJ ! It might spread the word to others....and I dont wash mine but about twice a year. No sense in giving it any ideas. It's a Jeep, not a Maserati !
__________________
Cajun Recipes and Fishing tips

Words of wisdom, Posted by Zeejay:
"..it's not air, it is the opposite of air... suckage so to speak."

Stalling? Work through Zeejay's list
Oldfrog is online now   Reply With Quote
Unread 05-25-2013, 02:45 PM   #15
eagsc7
Registered User
1994 ZJ 
 
Join Date: Apr 2013
Location: Sweetwater Cyt, WY
Posts: 432
Quote:
Originally Posted by Oldfrog View Post
Dont go spoiling that ZJ ! It might spread the word to others....and I dont wash mine but about twice a year. No sense in giving it any ideas. It's a Jeep, not a Maserati !
Twice a year... Shoot, I have yet to take our ZJ to the carwash. Our XJ only gets washed Once a year... IF THAT!
eagsc7 is offline   Reply With Quote




Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.