Maybe the PCM isn't the only problem?

lafittejeep

Member
Sep 6, 2018
73
70053
I have posted on this forum and have read many threads about issues with the PCM, Jeep stalling , hard shifting etc. I purchased a PCM for a company and installed this morning and the same thing that happened before the new PCM is happening. I had 3 shops all point to the PCM problem. This is my situation.. New PCM installed jeep starts right up very happy and hopeful. I let it run for about 45 min and engine kills just like it did with the old PCM. So thinking it may not be or partially the PCM. With the heat and expansion of everything could the cats be partially clogged and could that cause the engine to lose power and die? Still no codes have been thrown. Are there sensors that can be checked or changed that deal with temp that I should be looking for? I will be purchasing a scanner to get live data. 05 Wrangler LJ 138000 miles auto
 

skrelnik

TJ Enthusiast
Supporting Member
Jan 10, 2018
880
CT, United States
One time I dropped my 05 LJ at a reputable Jeep shop for a couple things. The guy calls me and says all is good but the Jeep stalls at every red light or stop sign. He kept it for a few more days and could nor figure it out. I brought it to a local mechanic who said the disributer (OPDA) was out of phase. He corrected it and all has been good.

Clogged cats is also a possibility.
 

Chris

Administrator
Staff Member
Sep 28, 2015
35,396
Salem, Oregon
I agree with what @skrelnik said.

In this case, since the PCM has been replaced, I highly doubt the PCM they gave you is bad. It sounds to me like it's definitely something else, even clogged cars.
 
OP
lafittejeep

lafittejeep

Member
Sep 6, 2018
73
70053
One time I dropped my 05 LJ at a reputable Jeep shop for a couple things. The guy calls me and says all is good but the Jeep stalls at every red light or stop sign. He kept it for a few more days and could nor figure it out. I brought it to a local mechanic who said the disributer (OPDA) was out of phase. He corrected it and all has been good.

Clogged cats is also a possibility.
"out of phase"? What does that mean exactly?
 

ohiopatriot

TJ Enthusiast
Jul 28, 2017
699
ohio
Clogged cats will cause a major power loss but if they're plugged that bad to cause it to die and not restart you'd notice the power loss long before now.

Does it just die like you turned the key off?

Check for spark and injector pulse. If you have them then check fuel pressure.

You might swap the ASD relay out with the horn relay or the like.
 

Len Mongeau

New Member
Jun 19, 2018
6
New England
I have the same issue. 2001 TJ SE 110,000 Auto. No failure codes.
Replaced TPS , fuel pump & filter & injectors. Cleaned tank also.
Does not act up in winter, warm moist temps seem to set it off.
$1000 later still having it towed.
Grrrrr.
 
OP
lafittejeep

lafittejeep

Member
Sep 6, 2018
73
70053
Ok, After installation of the rebuilt PCM, the engine fired right up and seemed very promising. Drove it on the road and transmission was shifting smooth. I let the engine run in my driveway and after 40 min the engine kills. Well after suggestions of checking all harnesses moving them around to hear for any changes in idle checking connections and getting a knuckle nicked by the fan blade (ouch). All wires and harnesses seem to be working fine. Then i switched the ASD relay with the horn relay just on a whim. The engine didnt die after 2.5 hours of running. I actually turn it off and started it back with no problems then I called it a night. So it seems that my problem was two fold. One the rough shifting caused by the PCM and the ASD relay which shut the engine down. Still feeling optimistic and will be driving it around to build my confidence. I will be posting who built my PCM when I can be sure it is stable. So thanks for all the suggestions.