post #1 of Old 10-10-2013, 11:54 AM Thread Starter
Blown5pnt4
Registered User
1997 ZJ 
 
Join Date: Oct 2006
Location: Huntington, NY
Posts: 94
help me fix this thing

My 97 4.0 zj has an intermittent stall thats driving me crazy. So far I've done the following

New cap
New rotor
New plugs
New msd coil
New air filter
New sensor in the distributor
Top end clean service from local shop
New battery

After all this it seemed to run amazing for a few days and now it's back to crap. I noticed the negative battery terminal looked a little mangled when swapping the battery so I'm thinking of changing that but not sure if it'll help. How many engine grounds are there ? where are they so I can try cleaning them ? Fairly confident its not the pcm as it was replaced 2years ago with a quality one as was the cps. I just want to stop wasting money on it. Lmk any suggestions. Thanks.


"When Lightning Strikes The Heartbeat Stops"
2001 F-150 Lightning #6065 of 6381 Built 08/09/01
Blown5pnt4 is offline  
post #2 of Old 10-10-2013, 12:35 PM
jm8881
Registered User
1996 ZJ 
 
Join Date: Oct 2005
Location: Palm Desert
Posts: 800
jm8881 is offline  
post #3 of Old 10-10-2013, 08:51 PM
CDRFunkmeyer
Registered User
1994 ZJ 
 
Join Date: Jan 2009
Location: Bellflower California
Posts: 83
No codes? yes I'd say the mangled negative battery cable could matter. The wiring harness should have it's own bolt in the bottom of the engine. Follow the harness back from the battery.

Commander Funkmeyer
___________________
1994 Grand Cherokee Limited 4x4, 5.2L magnum,
2" Lift, K&N Air Intake, rockrails, grillguard, full-rack, driving lights, hitchmount gas can/ spare carrier, Hydrogen Cell
CDRFunkmeyer is offline  
post #4 of Old 10-10-2013, 09:14 PM Thread Starter
Blown5pnt4
Registered User
1997 ZJ 
 
Join Date: Oct 2006
Location: Huntington, NY
Posts: 94
Quote:
Originally Posted by CDRFunkmeyer View Post
No codes? yes I'd say the mangled negative battery cable could matter. The wiring harness should have it's own bolt in the bottom of the engine. Follow the harness back from the battery.
The cables look good it was the terminal that was mangled looking. I put in new ones tonight as well as jiggled the pcm connections and swapped the fuel ppump relay. Seems good now but its done that before....

"When Lightning Strikes The Heartbeat Stops"
2001 F-150 Lightning #6065 of 6381 Built 08/09/01
Blown5pnt4 is offline  
post #5 of Old 10-11-2013, 09:46 AM
Donnyd21
Registered User
1998 ZJ 
 
Join Date: Sep 2012
Location: Moore
Posts: 165
Ecu
Donnyd21 is offline  
post #6 of Old 10-12-2013, 06:00 PM
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Posts: 8,550
anytime a PCM behaves for a few days after a battery disconnect, then starts crapping out, it is highly suspect.

when does the stall occur? at idle, cruise, accel? what happens to the gauges? lights? if the cruise is on, does it turn off when the the stall occurs?

are any codes stored?
ZeeJay1997 is offline  
post #7 of Old 10-12-2013, 06:10 PM
Oldfrog
Registered User
2007 WK 
 
Join Date: Feb 2008
Location: Louisiana/Texas
Posts: 5,091
Quote:
Originally Posted by ZeeJay1997 View Post
anytime a PCM behaves for a few days after a battery disconnect, then starts crapping out, it is highly suspect.
This ^

The making and breaking of the battery power can't be good for the PCM....and I 've always suspected that it's ONE of the causes of PCM failure. It it makes you feel any better, I'm on my 5th PCM and so far, so good....

2007 5.7 Hemi, Ltd. QD II -
1997 ZJ, 4,0 select trac, Up country, track lok.
Oldfrog is offline  
post #8 of Old 10-13-2013, 09:16 PM Thread Starter
Blown5pnt4
Registered User
1997 ZJ 
 
Join Date: Oct 2006
Location: Huntington, NY
Posts: 94
Quote:
Originally Posted by Oldfrog View Post
This ^

The making and breaking of the battery power can't be good for the PCM....and I 've always suspected that it's ONE of the causes of PCM failure. It it makes you feel any better, I'm on my 5th PCM and so far, so good....
Ugh I don't know if I have it in me to go thru 5 pcms lol.

Quote:
Originally Posted by ZeeJay1997 View Post
anytime a PCM behaves for a few days after a battery disconnect, then starts crapping out, it is highly suspect.

when does the stall occur? at idle, cruise, accel? what happens to the gauges? lights? if the cruise is on, does it turn off when the the stall occurs?

are any codes stored?
The stall generally happens after its been sitting for an extended amount of time. Like over night before work the next day. I can hit the remote start to warm it up for a few and it always starts right away. It normally then runs for around a minute then stalls itself. After a second for the remote start to reprime itself it starts and stays running till I get in it. Most of the time that's pretty much the end of it. But sometimes when Im driving to work, when Im approaching a red light on the brakes, it'll just die as if all power to everything was cut. Also sometimes When I get on it, like merging onto the highway or a busy road it'll stumble or die and very very rarely backfire. I don't know what else to replace.....Even though it was replaced I think a year or so ago Im starting to think it is the ecu again, but if I start it, and jiggle on the wires at the pcm it doesn't do anything. Doesn't force the stumble or make it run any smoother. Doesn't leave any check codes. Where is the best place to buy a PCM from ?

"When Lightning Strikes The Heartbeat Stops"
2001 F-150 Lightning #6065 of 6381 Built 08/09/01
Blown5pnt4 is offline  
post #9 of Old 10-13-2013, 10:27 PM
Oldfrog
Registered User
2007 WK 
 
Join Date: Feb 2008
Location: Louisiana/Texas
Posts: 5,091
I assume you've gone through Zeejay's list of 12 things to check?
( especially cleaning the throttle body and IAC )

Could still be the PCM, but disconnect the upper 02 sensor connector and see if anything changes. ( besides throwing a code for the sensor).

I am also assuming you have repaired the battery cables and cleaned and tightened all grounding points? ( battery, fender well, below the oil dipstick and below the coil)

Also check the crank sensor using this method:
https://www.youtube.com/watch?v=yp_kK6U8a64

As for where to get a PCM, you can PM Kolak here on the forum, or get an A1 Cardone brand from Oreilly's, etc. They run about $289 or so....give or take $50. But DO NOT buy one from either of those outfits in Florida !

2007 5.7 Hemi, Ltd. QD II -
1997 ZJ, 4,0 select trac, Up country, track lok.
Oldfrog is offline  
post #10 of Old 10-14-2013, 12:09 AM
ZJfamilyfun
Registered User
1998 ZJ 
 
Join Date: Mar 2013
Location: Alpena
Posts: 172
Quote:
Originally Posted by Blown5pnt4 View Post



The stall generally happens after its been sitting for an extended amount of time. Like over night before work the next day. I can hit the remote start to warm it up for a few and it always starts right away. It normally then runs for around a minute then stalls itself. After a second for the remote start to reprime itself it starts and stays running till I get in it. Most of the time that's pretty much the end of it. But sometimes when Im driving to work, when Im approaching a red light on the brakes, it'll just die as if all power to everything was cut. Also sometimes When I get on it, like merging onto the highway or a busy road it'll stumble or die and very very rarely backfire. I don't know what else to replace.....Even though it was replaced I think a year or so ago Im starting to think it is the ecu again, but if I start it, and jiggle on the wires at the pcm it doesn't do anything. Doesn't force the stumble or make it run any smoother. Doesn't leave any check codes. Where is the best place to buy a PCM from ?
Just a shot in the dark..........but have you thought to diag the remote start system???? Who installed it? A shop? You and a buddy? Are all the connections good?? Just a thought being its tied into the starting/ignition system.
ZJfamilyfun is offline  
post #11 of Old 10-14-2013, 06:54 AM
newfieZJ
Registered User
1995 ZJ 
 
Join Date: May 2008
Posts: 6,557
Quote:
Originally Posted by Oldfrog View Post
Could still be the PCM, but disconnect the upper 02 sensor connector and see if anything changes. ( besides throwing a code for the sensor).
O2 sensors can do some weird things . Most times , the issue develops during the warm up cycle where the PCM controls most everything on settings vs using the sensors . Case in hand , the 02 . One case I saw the jeep would go into convulsions for about 30-45 secs , run perfect before and after . Just one example . No CEL .

I'd have to try this before buying anything . A wanky 02 could be the issue . Should run fine with it disconnected , PCM will compensate .
newfieZJ is offline  
post #12 of Old 10-14-2013, 12:12 PM
chalkboard
Registered User
1997 ZJ 
 
Join Date: May 2013
Location: Las Vegas
Posts: 118
Clean/Lube PCM connections

I too faced the stalling issue with my '97 4.0. For me, cleaning the pcm connections, both sides with deoxit, and then applying pin-head amounts of dialectic grease to the female side connectors resolved my issues. I didn't just smear the grease on the female side. I made sure it made it into each independent female lead. The connector face remained free of grease.

OldFrog and ZeeJay know much more than I do about this issue, but that is what worked for me. I actually traced my problem to the number 7 pin.

Good luck!

2001 WJ 4.7/67k "Old Bones"
1997 ZJ 4.0/154k Sold
chalkboard is offline  
post #13 of Old 10-14-2013, 06:21 PM
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Posts: 8,550
Quote:
Originally Posted by ZJfamilyfun View Post
Just a shot in the dark..........but have you thought to diag the remote start system???? Who installed it? A shop? You and a buddy? Are all the connections good?? Just a thought being its tied into the starting/ignition system.
This crossed my mind also. When it's time to fish or cut bait, it would behoove you to disconnect the system and see if it's the problem. Any type of add on electronics on these things makes me nervous.
ZeeJay1997 is offline  
post #14 of Old 10-15-2013, 11:45 PM
kachink
Registered User
1998 ZJ 
 
Join Date: Sep 2010
Location: Lake Forest
Posts: 774
Your post above says it stalls when idling after a remote start and when braking. When I had a random stalling problem I finally noticed that it was only stalling when I didn't have my foot on the gas. I removed the throttle body and thoroughly cleaned it, including the IAC and the pocket under the IAC. It didn't stall again for a couple of years.
kachink is offline  
Reply


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



Posting Rules  
You may not post new threads
You may not 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