Jeep Grand Cherokee ZJ stalling FIXED!
by ColbyScottClark - 8/17/13 11:07 AM
Be patient and read, on this is a real solution to the stalling issue that will PERMANENTLY fix the jeep pcm curse. 99% of people who have resolved this problem have traced it to the pcm. Some replace it, some repair it and some choose to jerry rig it. With ZJ's most erratic transmission problems as well as many other hiccups are caused by the faulty pcm or Powertrain Control Module design! The transmission is part of the powertrain and so is also sometimes affected. Don't take your jeep to the tranny shop if your main problem is the stalling/ stumbling issue. I'm amazed by the number of seemingly intelligent people just throwing dozens of parts and repairs at these jeeps without a solid diagnosis or faulty engine codes. Sensors RARELY fail without sending off a fault code to the pcm and showing a cel. As for the fix of playing with the screws, straps and zip ties that is all nonsense. It is a voodoo fix! The so-called "methodical aircraft mechanic" who came up with the screw fix is a simpleton. The screws are nowhere near close enough to the board to short on it, they would have to be nearly an inch longer to penetrate the boards firm jelly-like potting and cause a short. Playing with the screws and straps merely jiggles the faulty solder joints within the pcm and temporarily restores contact. I have a 96' limited 4.0 with 190xxx and had the stalling plague me for nearly a year before I bought an audi to make sure I had a reliable vehicle should the stalling rear its unpredictable ugly face and leave me stranded. I am a marine outboard mechanic and so I chose to keep the jeep refusing to believe that my mechanical ability was not adequate to keep my beloved jeep running well. Drawing on deep reserves of patience and self control backed by the knowledge of this being a common problem and hard to diagnose I refused to buy any parts but one of the few that can fail without showing a cel. The crank sensor. This seemed to appease the jeep for all of two days! At this point I knew that throwing parts at it was senseless, the problem has all the symptoms of an electrical short or poor connection not a parts failure. And so the jeep sat in my shop for months while I tore through the wiring harness and connectors, searching for shorts or breaks. I feverishly prowled the internet searching for a reasonable sensible seeming solution. Replacing the pcm was not an option for me, most people who had success did resolve their problem this way but often it too is a temporary fix. In my experience individual electrical components such as diodes resistors and capacitors do not sometimes work and at others not. They either burn up and fail completely or they work all the time, outside of a failure most electrical problems can be traced to a shorted or poor connection. I knew my computer was fine because sometimes it worked, nevermind when it didn't work I knew nothing was blown because sometimes it DID work. Finally I found the solution on the web provided by a TRULY methodical individual, here is the link to it
This fixed my problem completely 6 months ago! I waited all this time to post to be sure it is a rock solid fix. I'm now sure it is, my jeep has been running and idling stronger than it ever has in my nearly 5 years of ownership! I did have a little trouble getting the solder to flow properly, my solution was to throw a piece of 2"x3' 1/4" angle iron in my oven at 350* for ten minutes. I took it out, laid it on my bench and then laid the piece of the pcm I was working on on it to prevent its metal backing from acting as an effective heat sink and pulling heat from the solder joint. Good luck to you guys and thanks bikedawg69 for this free and simple real solution! Keep Jeepin!