Looking for guidance after a PCM swap... - JeepForum.com
Reply
 
LinkBack Thread Tools
post #1 of 18 Old 11-27-2018, 01:14 AM Thread Starter
Kokala
Registered User
1997 TJ Wrangler 
 
Join Date: Nov 2018
Location: Honolulu
Posts: 6
Looking for guidance after a PCM swap...

I am no mechanic and have learned a lot form the forums. After much research and testing using these forums as reference, I decided my PCM was failing. Symptoms were, fuel pump not shutting off after 3 seconds coupled with the gauge cluster not waking up until after several attempts at turning the key on and off. I decided it was the PCM because after replacing the fuel pump the problem persisted and when the gauge cluster would finally wake up the Jeep would fire and run like a champ. Finally, the Jeep quit starting all together. It has sat for about 4 months.

After installing the new PCM the fuel pump and gauge cluster behave normally. The jeep turns over strong and starts but dies instantly. If I hit the gas I can get one or two revs out of it before it dies. It sounds normal in that instant. No sputter, it shuts off like the key was removed. I have cleaned the IAC and replaced the TPS after getting the code P0123. I back probed the TPS before replacing it and had voltage from .8 to 3.9 from closed to open. The new TPS gives the same reading.

Any thoughts? I have a sinking feeling the PCM is still the issue... Any help is appreciated!

`97 Wrangler Sport
4.0 L
Manual
No mods
Stock


Last edited by Kokala; 11-27-2018 at 01:15 AM. Reason: Formatting
Kokala is offline  
Sponsored Links
Advertisement
 
post #2 of 18 Old 11-27-2018, 05:50 AM
tsc
Registered User
2006 LJ Wrangler 
 
Join Date: Mar 2007
Location: Pacific Northwest
Posts: 531
Any chance your rig has sentry key? Where did the new pcm come from?
tsc is offline  
post #3 of 18 Old 11-27-2018, 06:47 AM
2jhanna
Web Wheeler
2002 TJ Wrangler 
 
Join Date: Jun 2007
Location: Denton County, TX
Posts: 8,884
Quote:
Originally Posted by tsc View Post
Any chance your rig has sentry key? Where did the new pcm come from?
This was my first thought also, either his rig, or the new pcm.

Another thought is to go back to your old pcm and see if symptoms go back to original.

I am multi-talented, I can talk and piss you off at the same time.

jhanna
denton county, tx
2jhanna is offline  
 
post #4 of 18 Old 11-27-2018, 12:55 PM Thread Starter
Kokala
Registered User
1997 TJ Wrangler 
 
Join Date: Nov 2018
Location: Honolulu
Posts: 6
Quote:
Originally Posted by tsc View Post
Any chance your rig has sentry key? Where did the new pcm come from?
I too was thinking security system.

My rig does not have any security key. I'm not familiar with how they are integrated when present. Is it possible the PCM is looking for one?

Quote:
Originally Posted by 2jhanna View Post
Another thought is to go back to your old pcm and see if symptoms go back to original.
I went back to the original PCM and got the same symptoms. Fuel pump running continuously, or running for 3 seconds pausing then running continuously. Fuel and voltage gauge doe not function on the cycles when the fuel pump runs continuously but will "wake up" occasionally. Crank but no start.

Installing the new PCM after that, the Jeep starts up strong and dies nearly instantly. I can still get one or two good revs.

Quote:
Originally Posted by tsc View Post
Where did the new pcm come from?
PCM is from Flagship One. The unit they sent has a factory code on it that matches a 96 Cherokee, automatic, and different engine size. I contacted them before installing and they assured me the internals matched what I had purchased....... Looks like I'm a sucker.

I'm am probably going to return this one as I'm pretty sure it's the problem. Is there any other reputable resource for PCM's these days? It doesn't look like Cardone makes them any more, so RockAuto and the chain stores have none available.
Kokala is offline  
post #5 of 18 Old 11-27-2018, 03:52 PM
Jonny Jeep
Web Wheeler
 
Jonny Jeep's Avatar
1997 TJ Wrangler 
 
Join Date: Feb 2007
Location: Manchester
Posts: 6,159
97s didn't have sentry key so if the new PCM is a 97 or is programmed as a 97 it shouldn't be an issue. If it's a 98-99 PCM, the 97 dash doesn't have the sentry key light so I don't know how you'd easily check if the PCM has sentry key programmed.



As the Jeep has been sat for four months could it be the battery has enough charge to start but is then low enough that the engine will struggle to run?
Jonny Jeep is offline  
post #6 of 18 Old 11-27-2018, 06:44 PM
rcroane
Member
2006 TJ Wrangler 
 
Join Date: Dec 2011
Location: Springfield
Posts: 268
Quote:
Originally Posted by Kokala View Post
I too was thinking security system.

My rig does not have any security key. I'm not familiar with how they are integrated when present. Is it possible the PCM is looking for one?



I went back to the original PCM and got the same symptoms. Fuel pump running continuously, or running for 3 seconds pausing then running continuously. Fuel and voltage gauge doe not function on the cycles when the fuel pump runs continuously but will "wake up" occasionally. Crank but no start.

Installing the new PCM after that, the Jeep starts up strong and dies nearly instantly. I can still get one or two good revs.


PCM is from Flagship One. The unit they sent has a factory code on it that matches a 96 Cherokee, automatic, and different engine size. I contacted them before installing and they assured me the internals matched what I had purchased....... Looks like I'm a sucker.

I'm am probably going to return this one as I'm pretty sure it's the problem. Is there any other reputable resource for PCM's these days? It doesn't look like Cardone makes them any more, so RockAuto and the chain stores have none available.
Reviews for Flagship One are really bad. Most info I have read says buying from any internet PCM builder is a real crap shoot. There is one guy who has posted having good luck with Modulegods. Have you tried sourcing one remanufactured by Chrysler?
rcroane is offline  
post #7 of 18 Old 11-27-2018, 07:30 PM Thread Starter
Kokala
Registered User
1997 TJ Wrangler 
 
Join Date: Nov 2018
Location: Honolulu
Posts: 6
Quote:
Originally Posted by Jonny Jeep View Post
97s didn't have sentry key so if the new PCM is a 97 or is programmed as a 97 it shouldn't be an issue. If it's a 98-99 PCM, the 97 dash doesn't have the sentry key light so I don't know how you'd easily check if the PCM has sentry key programmed.



As the Jeep has been sat for four months could it be the battery has enough charge to start but is then low enough that the engine will struggle to run?
I sure was hoping there was a way to determine if the PCM was looking for a sentry key.

I have it at AutoZone for an overnight charge and test. Battery is 3 years old and right at the end of the Costco warranty.


Quote:
Originally Posted by rcroane View Post
Reviews for Flagship One are really bad. Most info I have read says buying from any internet PCM builder is a real crap shoot. There is one guy who has posted having good luck with Modulegods. Have you tried sourcing one remanufactured by Chrysler?
I was super hesitant to try from them based on their reviews. Their ebay store has them at over 95% so I thought that might be a safer, proven channel. Everyone I looked at seemed like a crap shoot. I never stumbled across a source by Chrysler. Mopar doesn't have any. I'll take a look a Modulegods in the event I return this one. Without quality rebuilders, when these computers go does that mean our trucks just die?
Kokala is offline  
post #8 of 18 Old 11-28-2018, 06:50 PM
rcroane
Member
2006 TJ Wrangler 
 
Join Date: Dec 2011
Location: Springfield
Posts: 268
Quote:
Originally Posted by Kokala View Post
I sure was hoping there was a way to determine if the PCM was looking for a sentry key.

I have it at AutoZone for an overnight charge and test. Battery is 3 years old and right at the end of the Costco warranty.



I was super hesitant to try from them based on their reviews. Their ebay store has them at over 95% so I thought that might be a safer, proven channel. Everyone I looked at seemed like a crap shoot. I never stumbled across a source by Chrysler. Mopar doesn't have any. I'll take a look a Modulegods in the event I return this one. Without quality rebuilders, when these computers go does that mean our trucks just die?
You'll need to go through a dealer to get a Chrysler re-manufactured one. Not sure about your year, but really tough to find one for '05's and '06's.
rcroane is offline  
post #9 of 18 Old 11-28-2018, 09:44 PM Thread Starter
Kokala
Registered User
1997 TJ Wrangler 
 
Join Date: Nov 2018
Location: Honolulu
Posts: 6
Welp... no luck with leaving my battery at the store overnight. They say it load tested fine, 89%. Jeep cranked and started again but died.

At this point I'm stuck. Googling the symptoms I keep getting SKIM key which I don't have. I'd be willing to throw $80 at a MAP or IAC if anyone else thinks it's worth it but I am not sure they are the issue.

I'm going to start looking for a new PCM again. I'll check with my dealer for sure.

Anyone have a source for a PCM that fits a `97? Used or remanufactured?

Anyone used a service that has repaired their PCM they can recommend?
Kokala is offline  
post #10 of 18 Old 11-30-2018, 10:44 AM
LafitteJeep
Registered User
 
LafitteJeep's Avatar
2005 LJ Wrangler 
 
Join Date: Aug 2018
Posts: 32
Quote:
Originally Posted by rcroane View Post
Reviews for Flagship One are really bad. Most info I have read says buying from any internet PCM builder is a real crap shoot. There is one guy who has posted having good luck with Modulegods. Have you tried sourcing one remanufactured by Chrysler?
I am that one guy that used ModuleGods and over 1600 miles and running fine.
LafitteJeep is offline  
post #11 of 18 Old 11-30-2018, 10:46 AM
LafitteJeep
Registered User
 
LafitteJeep's Avatar
2005 LJ Wrangler 
 
Join Date: Aug 2018
Posts: 32
Quote:
Originally Posted by rcroane View Post
Reviews for Flagship One are really bad. Most info I have read says buying from any internet PCM builder is a real crap shoot. There is one guy who has posted having good luck with Modulegods. Have you tried sourcing one remanufactured by Chrysler?
Quote:
Originally Posted by rcroane View Post
You'll need to go through a dealer to get a Chrysler re-manufactured one. Not sure about your year, but really tough to find one for '05's and '06's.
ModuleGods did mine over 1600 miles ago. I was under a different user name. I would also check the ASD relay. Swap it out for another just to see if the engine will stay running.
LafitteJeep is offline  
post #12 of 18 Old 12-01-2018, 09:17 PM
chevymad
Registered User
2003 TJ Wrangler 
 
Join Date: Oct 2012
Location: Skamokawa
Posts: 124
Had a jeep come in recently that had the pcm replaced. Same symptoms. New pcm had been flashed with skim enabled even though the jeep had no skim. Trailered it to the dealer for a reflash and it works.
chevymad is offline  
post #13 of 18 Old 03-07-2019, 11:06 AM
Andyduck
Registered User
 
Join Date: Mar 2019
Posts: 4
Autozone had a good PCM for me.It took three days to get it though.You might try a new cranckshaft position sensor.
Andyduck is offline  
post #14 of 18 Old 03-07-2019, 04:47 PM
dbbd1
Senior Member
 
dbbd1's Avatar
2006 TJ Wrangler 
 
Join Date: Aug 2008
Location: Oregon
Posts: 991
Quote:
Originally Posted by Andyduck View Post
Autozone had a good PCM for me.It took three days to get it though.You might try a new cranckshaft position sensor.
How much was yours from a-zone?

The opinions of worthless people, are worthless.

The only problem that you have with anyone in this world, is what you expect of them.

Society is no match for a stupid person.

"Life Is tough but it is tougher when you are stupid"

-John Wayne
dbbd1 is offline  
post #15 of 18 Old 03-08-2019, 09:44 PM
Andyduck
Registered User
 
Join Date: Mar 2019
Posts: 4
a zone pcm

the core charge was $100 the part was $169.Make sure you have the VIN # on hand and the miles with you before you go down there.They had it shipped to my door instead of to the store which I thought was quite convenient.It came from Blue Streak Electronics.I don't know if you can order directly from them or not
Andyduck 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











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 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