Are all PCMs bound to fail? - JeepForum.com

 
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post #1 of 9 Old 04-05-2013, 04:56 PM Thread Starter
GRN74cj5
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1998 ZJ 
 
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Posts: 33
Are all PCMs bound to fail?

I'm trying to do some preventative maintenance to the 127K mile 98 ZJ. We've had it 2 years now and the first thing to go was the radiator. With your help, I swapped it out for a CFS and I haven't had any issues. The fuel pump left my wife sitting, it was replaced and a few months later the check valve is letting fuel drain back into the tank. I have a bosch ready to replace it since we're tired of turning the key to on 3 times. I also have a new Mopar CPS ready to go in. I'm trying to address common problems before they occur and leave us sitting again. Lately I have been reading about the PCM issues many of you have had. I've been wondering if there is anything that can be done to prevent the known problem or is it age related? Mine is working fine (knock on wood). To me, that harness appears to put a lot of stress on the connectors, especially while on a bumpy road. There is a white colored tie that holds it to the firewall, but that appears to be it. Perhaps some large zip ties could be placed around the PCM to help stabilize things to limit shock to the connectors. I also wonder, are there ZJs that have really high miles and still have an original perfectly functional PCM? Maybe there were good ones and bad ones.

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post #2 of 9 Old 04-05-2013, 05:26 PM
leadfootny
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1996 ZJ 
 
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Most of the failing computers are of the 93-95 variety. The older models were susceptible to corrosion. Both of my zj's are on their original pcms with no problems (I should knock on wood). 256K on the 96 and 183K on the 98.

96 ZJ 4.0
98 ZJ 5.9
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post #3 of 9 Old 04-05-2013, 05:40 PM
ZeeJay1997
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Be sure you don't have any exhaust leaks forward of the firewall. My theory is the extra heat has a detrimental effect on everything under the hood. No proof that this is the case, but it makes sense... to me anyhow...
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post #4 of 9 Old 04-06-2013, 05:24 PM
mholmes7979
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PCM's are electronic devices and subject to failure due to heat but, don't fix it if it ain't broke. I have a 1994 and yes it broke.
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post #5 of 9 Old 04-06-2013, 05:55 PM
Exdecuk
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1998 ZJ 
 
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I had a Mopar PCM in my 9er, parked it up for 2 years, went back to it and it was shot. Running the original again now till i get round to a Hemifever tune. The Mopar PCM had about 30K kilometers on it from new over about 6 years.

A man will pay $2 for a $1 item he needs.

A woman will pay $1 for a $2 item that she doesn't need but it's on sale.
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post #6 of 9 Old 04-06-2013, 06:29 PM
jnowak
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93 with 289k knock on wood still going on original
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post #7 of 9 Old 04-07-2013, 01:17 AM
cootertwo
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1997 XJ Cherokee 
 
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Like some have said, it's an electrical item. Some last, others don't. Like some televisions, some seem to go on forever, many die too soon.
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post #8 of 9 Old 04-07-2013, 02:20 AM
UAE59
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most 97-01 cherokee PCM go bad faster than old models and they are easy to fix .. this what i saw
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post #9 of 9 Old 04-07-2013, 05:06 AM
ratmonkey
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Quote:
Originally Posted by GRN74cj5 View Post
I'm trying to do some preventative maintenance to the 127K mile 98 ZJ. We've had it 2 years now and the first thing to go was the radiator. With your help, I swapped it out for a CFS and I haven't had any issues. The fuel pump left my wife sitting, it was replaced and a few months later the check valve is letting fuel drain back into the tank. I have a bosch ready to replace it since we're tired of turning the key to on 3 times. I also have a new Mopar CPS ready to go in. I'm trying to address common problems before they occur and leave us sitting again. Lately I have been reading about the PCM issues many of you have had. I've been wondering if there is anything that can be done to prevent the known problem or is it age related? Mine is working fine (knock on wood). To me, that harness appears to put a lot of stress on the connectors, especially while on a bumpy road. There is a white colored tie that holds it to the firewall, but that appears to be it. Perhaps some large zip ties could be placed around the PCM to help stabilize things to limit shock to the connectors. I also wonder, are there ZJs that have really high miles and still have an original perfectly functional PCM? Maybe there were good ones and bad ones.
The zip ties are the previous owners attempt at fixing a bad connection that many 96-98 computers experience. You'll need to fix the solder joints or buy a new one sooner or later.
It's supposed to be bolted to the firewall with three torx head bolts.
Quote:
Originally Posted by Exdecuk View Post
I had a Mopar PCM in my 9er, parked it up for 2 years, went back to it and it was shot. Running the original again now till i get round to a Hemifever tune. The Mopar PCM had about 30K kilometers on it from new over about 6 years.
This is an extremely common failure method for dodge computers. So common in fact that many salvage yards wont sell them. They go bad just sitting around with no power.
Had you left a battery tender on it and started it once a month it wouldn't have gone bad.

'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.

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