Jose Calderon

So I've been having a problem with my 1996 grand Cherokee. it's a straight 6 nearing 195k miles and is my dd. I'll try my best to explain everything that's happened step by step.
The whole problem started about a year ago when it started stalling on me. I tried replacing ignition switch, ignition coil, and crankshaft position sensor. it all seemed to help but codes kept coming back and kept stalling. I decided to replace my computer and after that it hasn't happened until about 2 weeks ago. when it stalls it starts misfiring pretty bad and just dies on me. all my gauges still read fine and nothing flickers or loses power, it dies how it would when you run out of gas. so I replaced my fuel filter thinking it was a fuel issue, but that didn't change anything.I metered all my fuel injectors and cleaned them, then I checked fuel pressure and did a fuel pressure drop test and everything seemed fine, but at the time I checked it my jeep was also starting first try. I checked fuel pressure while the problem was happening and fuel pressure was still fine, so that rules that out. I had an ignition coil code come up and replaced that right away and still stalling. Igniton coil code came back up so I thought something obviously isn't right. I replaced it again under warranty, then replaced distributor cap, rotor, spark plugs and wires and still having the same problem. im starting to think it's a computer/connection problem? going to try zip tying the connectors to the computer and put electrical grease on them when I get off work today. if someone can think of something I haven't tried yet please help, I have my work vehicle today, but have to drop it off tonight and really need the old jeep going again. (I still have the coil code also)

xjmachine

yes you are right, that sounds like a computer issue. when you have it running try shaking the wire harness where it connects to the pcm. see if it stalls or acts weird. a couple of years ago this was happening to me, so i replaced the pcm and it still kept happening, turns out the pcm i bought at orileys was faulty. so that is a possibility for you as well. (remember parts like that are not new they are "rebuilt" from old ones) so they traded for another one, and hasnt happend again
good luck sir, keep us posted

Jose Calderon

Okay I'll try that later today when I mess with it again. I got mine about a year ago from Oreilly also. Did they trade yours out free? If so I might just take it there and swap it before I zip tie the harnesses to it. Thanks for the reply!

xjmachine

yeah they did but i figured it was bad within a week of getting it. doesnt hurt to ask if you figure thats the issue

Jose Calderon

Yeah I'll definitely at least try. I'll post again after I've done all that

Jose Calderon

Problem fixed!!....for now lol.
Yesterday after work I started it and wiggled the wire harness, then what do you know.. Jeep turns off.
Zip tied the connectors nice and tight, shook the PCM a little and no stalling. Test drove it and drove over some bumps and cruised around for about 30 min and still good! Of course it would be something so simple after all the headache lol. Oh well, learning experience I guess

xjmachine

glad to hear it. hope them zipties hold up for a good while

Jose Calderon

Yeah me too. Worst case I have to buy new pig tails for them and splice a good hundred wires lol

MsCin

I to replaced the PCM and it made no difference, I do belive its in the wiring harness from the fuse box to the computer. For some reason Jeep hasnt done the best job protecting the computer connections from the elements, I still have the issue and ready to run it off the cliff. By cleaning up the connections it does help but it is short lived maybe a few good weeks.

dave1123

Are you good with a soldering gun? Take the PCM off the jeep and open it up. Check all the connections to the terminal strip for cracks in the solder. You may have to "unpot" it, that is remove the plastic foam packing around the circuit board. Since they went to lead free solder, cracks have been a problem. I'd use standard electronic leaded solder if you can find it.

MsCin

Im thinking that may be out of my scope of skills at the moment but I will do research on it. I did remove and replace the PCM so Im aware of how to R/R and will take your suggestion perhaps find someone to help with the inspection of the board. Anything at this point would be helpful, its fustrating and Im way past the point of throwing parts at it. I just dont get why if its a PCM problem it is not setting a code. Only a random code ever set misfire in Bank 3 which I should know the code by heart now ... lol


thanks again Cindy

Jose Calderon

Try cleaning the connectors and putting some electrical grease in them. This won't necessarily keep a good connection but it will keep moisture and dirt from getting in. Then take some big zip ties and put them around your computer to fasten the connectors to it. Did this to mine and haven't had the problem since

MsCin

I did some research on you tube from a good tutorial of how to open the pcm and check the pins, I think this is something can do. Actually Im pretty excited to try the soldering will report back on how it goes. Thanks bunches !!

Jose Calderon

Good luck, keep us posted!

Bonnie Perron

I had the same issue(stalling) and I Replaced the PCM ...still had a misfiring issue after that...so I added another ground from the firewall to the block and my jeep has ran great ever since! BTW.... o'reilleys sells faulty parts....I don't care what it is....if it's from o'reilleys....it's broken!!