Posted on 12/31/2011 7:04:50 AM PST by Blueflag
Need help from people with Jeep mechanical electrical experience/diagnosis. Our 1996 Jeep Cherokee Country (classic, not Grand) 4.0L I6 4WD has started to have a repeating and random sudden loss of power (engine quits with NO dash warning lights on dash). Need suggestions from people who have been there and done this. I am a fairly savvy and experienced car mechanic on my own, and this has me baffled. See Body of Comment for details.
Efforts so far: New fuel filter, (no water in fuel) new coil, cap, rotor and wires. One can of Dry Gas (SeaFoam) added just in case. New fuel cap (in case not venting) No OBP codes indicating (so not crank position sensor or fuel vent solenoid) No check engine light when operating. Runs great when 'normal' 94,000 miles on odometer (all ours)
NOTE AGAIN, when the engine stalls, remember that NO lights come on like they would if I had a fuel starvation problem. That to me points to a bad/loose connection SOMEWHERE in the low voltage side of the ignition circuit.
SO ... Has anyone encountered this before with their Jeep Cherokee, who might be able to point me to the most likely fault ... so I don't have to start checking for loose grounds one by one using the wiring diagram?(aaaarrrggghhh)
Sounds like the neutral switch on the automatic
xmission. These can be a real pita.
I’m neither a mechanic nor an engineer, but my first guess would be a failing control module.
wifie had the same problem with her jeep... neutral safety switch is probably the culprit... this is located in the console near the gear selector...remove console, locate switch and replace..
“I’m neither a mechanic nor an engineer, but my first guess would be a failing control module.”
Yes, sounds like a computer module box (CCM) going bad. Had an F-100 Ford pickup that did this. Would just die like you turned the ignition off while driving. No bucking or lights on the dash because for all intents and purposes, it was like turning the key off.
Try replacing the O2 sensors.
5.56mm
yeppers. found several comments on Jeep forums that said replace the reverse light switch and the stalling goes away. You never know what affects what on modern wiring harnesses.
It’s a good idea/hint, because I noticed last night that when my daughter backed the Jeep up in our driveway that her backup lights did not immediately illuminate. So that switch *IS* iffy anyways. Good idea to do it as part of the shotgun effort.
This idea is repeatedly mentioned on the various Jeep forums as an idea. They’re only about $100, so ...
Not definitive. But again, a good idea in the shotgunning process.
This sounds like it could be a sticking neutral safety switch. However, if there is a complete loss of power at the moment it quits (no headlights, etc) you might have a short somewhere in the forward wiring harness. And as another posted, it could be the control module.
It sounds like it might be a problem with the ignition system. I had a problem like this (not Jeep) several years ago where the electrical connection through the firewall would vibrate loose and cause total electrical failure including the loss of headlights. It was quite challenging when it happened at night.
Pickup plate sensor in the distributor....
Sweet. So far two posts on FR (most reliable) and 7 on the forums (generally questionable) about this switch contributing to a random stall.
thanks for the verification.
FReepers are the best, as always.
I had a similar problem with an old Dodge. I was about to buy a new car when I mentioned it to the owner of the local parts house. He said, “Oh, it’s a short in the cable harness at the base of the steering column.” Obviously, it won’t be exactly the same for the Jeep, but if you call the dealer and simply ask or go to a couple of parts houses and ask you may find that whatever it is happens so frequently it’s well known. You might also look for a Jeep forum. Such websites often allow you to ask questions and I’ve been helped numerous times by total strangers. (One sent me a detailed procedure with photos on how to change a cam position sensor that I couldn’t find even though I had the replacement part in my hand.)
It could be that the computer is going bad. That seems to be a recurring problem with Jeeps, it happened with ours, and things get worse until it just isn’t at all reliable.
There is a place in Florida that rebuilds computers and sends it back to you to install.
O2 sensors replaced 1500 miles ago (prior to this problem) and I checked the connections/ grounds there yesterday on both of them. These sensors are a prime suspect. The good news is that they will throw an OBD code generally when they are acting up or have intermittent connection issues. No codes and verified tight yesterday when I was under the vehicle.
Thanks though — it’s a good idea.
oh, and need to add this to my reply to you...
.45 ACP
.223
12 gauge
;-)
Hubby has this advice to check to see if it is the computer:
Unbolt the computer from the upper left firewall inside the engine compartment.
Leave everything connected, just unbolt.
Start the engine.
Shake the computer box.
If your car stalls, that indicates the computer is the problem.
Good call, but EVERYTHING else (headlights, radio, dome light, etc) continues to operate just fine.
I am thinking I will get the reverse/neutral switch and replace it. This is SOOOO typical of weird gremlins like this — that a seemingly unrelated device introduces voltage errors on the harness triggering other problems. SO hard to diagnose unless others have done the hard work for you.
Thanks!
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