50.Cal

I have a 2 part question, maybe I should put this in two posts but Ill try this first.

1) My 94 Grand Cherokee stalled out yesterday while I was idling at a stop light. It started right back up but stalled again. The rest of the ride home I would put it in natural at stops and slightly rev it so it wouldn't die. When I got home I let it idle, it didn't die that time. I have read a few things on it including crank case sensor, cpm screws, or a new cpm. I do also know my tranny is on its way out, not sure if that would do it, It slips at times and lurches at stops sometimes.

2) The second part of the question deals with the cpm. So I have seen them from $200 to $300. If it fixes the problem thats fine but I'm also at a point where I don't know if my jeep is worth it. I got it from a guy who took it off road a lot and did a lot of back yard mechanic stuff to it. My concern is some of the doors and the hood are not lined up very well, slightly off. He said he was never in a accident but you know how that goes, people lie about that stuff all the time. I checked out the frame, uni-body, myself and its looks ok but I'm no pro on that topic. I don't want to start putting a bunch of money in the Jeep if its not worth it, frame/uni-body is jacked. I called an auto shop to see if they would measure it to see its its good but couldn't find any that would. I did that in California for classic cars but I guess Jeeps are different? Any suggestions? Thanks and sorry for the long post.

jon-d

the PCM goes bad at the solder joints located inside of it. easy fix, just pull it out, disassemble and where the pins come in contact with the board its those joints that go bad. I would do that before buying a replacement.


all that other stuff should be checked as well. make sure the CPS is a mopar part, not aftermarket.

50.Cal

Ill give that a shot. Also, I noticed that the problem went away when I hit about 1/2 tank. I filled it up again today and I started having the issue again. Does a full tank have anything to do with the problem?

blueseasons

I would not assume it is the PCM. When mine went out, it would stall and start back up. As time went on the amount of time in between the stalling and restarting lengthened. It gave no warning before it stalled and it would stall at any speed. Revving it would not have stopped it from stalling. I can't help you figure out what it is, but I doubt it is the PCM.

50.Cal

The more I dig into it thats what I think it is to. I guess ill drop $300 on it. Thank you guys for the help and I hope you are cool in Santa Cruz, I know you guys got hit with a ton of rain and hwy 17 is out?

blueseasons

I don't know. It might be worth a half hour labor at a local garage before you buy the PCM, just to be sure. I am no mechanic, but of all the posts I have read concerning stalling, and PCM's, reviving the engine never stopped it from stalling if it was the PCM. If you do decided to get the PCM, I'd go the Cardone route through your local parts supplier before i'd get one off EBAY or from the jobbers in Florida. My Jeep developed a intermittent stalling problem, after I replaced the PCM. After checking that it was not the cam or crank sensor, I peeled back the insulation in my battery cables, I cleaned out any remaining corrosion, trimmed them back a bit to clean wire. I replaced the connectors to my battery posts. I bough the type that allowed me to feed each wire from the harness to each side of the post. I had read that the WJ's need good clean consistent electricity and apparently that did the trick for me.

Might be worth checking out for 3 bucks. https://www.delcity.net/store/Univer...obuxoC3dbw_wcB

dave1123

Here's an off-the-wall thing to check. I only mention it because it just so happened to be a problem with someone else's jeep. Check the fuel tank straps. If one or both straps break, the tank drops onto the shield and stretches the fuel lines with a full tank, then allows full flow as it empties. This could also cause stumbling on turns. I know it sounds stupid, but check them anyway.

50.Cal

Thats pretty interesting. I checked mine and they are good. I also have new battery cables on it. I ordered a crank position sensor as well. I am going to try to open my PCM tomorrow and clean it up and maybe solder the points. Im a bit scared ill mess it up though. I have watched a few videos on it. Would I use regular solder or is there any special kind I need?

Also, I saw some people were having this problem and they replaced their o2 sensors and it fixed the issue. Mine isn't going a code though so I'm not sure. I guess 1 crank sensor, 2 clean solder pcm, 3 o2 sensor?

dave1123

The reason we have so much trouble with solder joints now is they use lead free solder which turns brittle. If you can find some leaded electrical solid core solder, flash them all!