1996 XJ Intermittent Stalling
 

So I bought this Cherokee about a year ago, it has had its issues but for the most part it has run fine, no stalling or anything like that up until 2 months ago. I took it out in the desert and basically redlined the thing... And I am a huge idiot because its 2wd haha. Anyways, after doing doughnuts in the dirt, I took it back into the roads and bam, it stalled on me. I figured it was just way to damn hot, let it sit for a couple of minutes and it started back up just fine, no problems.

2 weeks later it stalls again, completely random. I think I was driving to get groceries. It started back up immediately. And then it happened a week later, and it eventually got to the point where it was stalling every day. I have replaced:

-CPS/CKP
-TPS
-fluids/oil/coolant all up to date and new
-starter
-plugs and caps
-distributer
-fuses and relays
-Brake Switch sensor
-crank position sensor coil
-Tranny filter

Some of these parts will seem to do nothing with it stalling, thats because a while back my tranny filter was clogged and it wouldn't shift out of 1st gear (I was an idiot). I replaced a couple of parts and eventually the filter which solved it. Those parts I listed are off the top of my head, I know I have replaced more.

Here is where it gets interesting. I installed a thermostat in about 2 weeks into it stalling. It did not have one when I bought it off of craigslist. Put it in there, and it stalled even more. Recently, I took it out and as soon as I did that, the stalling issue seemed to go away completely. Ran for about 2 weeks stall free. One thing weird did happen though, about 1 week into it running fine, it did not start up right away (after not running it for a while) due to vapor lock. Always got it to start though within 30 seconds.

Now, unfortunately, it stalled again today. And it did not start up right away; it had vapor lock again. I got it to start again but still, the whole issue pisses me off. I feel like there has got to be something with my fuel rail. This vapor lock and shutting off thing seems like they are hand in hand. It never had vapor lock in the past when it would quit but now it does. Also, very important, it is also giving me a check engine; code P0420 from my obd. Looked it up and said it was probably the cat converter efficiency. Sorry for the novel, but any suggestions?? This again is a 1996 Cherokee 6 cyl 4.0 liter 2wd. Thanks

Investigate your fuel pump.
The pump can fail intermittently prior to full failure.
When stall happens. Can you hear your fuel pump when trying to restart?

^ what he said...fuel pump

deff sounds like a pump issue, as for the code, when is is cool, hit the cat with your hand or shoe, a bad cat will USUALLY have dislodged material inside that you can hear by doing this. i would suggest (depending on your state) a universal cat which you can get under $200, or a dummy cat, around $40, or if you can get by with pipin it. there are 2 main ways to keep from gettin a CEL. one is a small peice of pipe that keeps the downstream 02 sensor out of the mainflow and the second is a resistor in the downstream 02 sens wiring. i would do this soon, because if your cat is clogged or has plates broken it will get quite hot and usually ruin the downstream 02 sensor that is screwed in the back of the cat itself(about a $40 part)

X2 on sniffing around the exhaust/cat. If your exhaust has leaks it gets out of the blue stoppages. O2 sensors going crazy. Sending weird input.

First off, stop beating yourself up. You took your cherokee out to do what it's meant to do, and when it broke you came here looking for help instead of throwing it away, so you're automatically not an idiot. Idiots will run a car hard and not understand why it breaks when it breaks. Anyway, there are a few things that can be causing this issue. First and foremost, rule out the most obvious by checking for fuel pressure and spark AFTER IT STALLS.

If you have no spark and no fuel then you either have a bad CPS (which you already said you replaced), a blown fuse or you shook the grounds loose on the computer.

For fuses, check all of them, but more specifically look in the main fuse block under the hood for a green 30 amp MAXI fuse that would be labeled for the ECM. Also check for a green 30 amp micro fuse. This one normally isn't labeled for anything, but it is the ASD fuse and will sometimes blow when the O2 sensor wires short out, causing you to have a no-start issue. Since this is more or less an intermittent issue, my money is not on the fuses but it never hurts to rule them out before you start swapping parts.

As for the grounding wires, there are a couple of locations for these, but the main one that I have in mind runs to where the engine oil dipstick is bolted on to the block on the passenger's side. Give those a good tug to make sure they're attached well enough, and inspect the wires for damage. It also wouldn't hurt to check the connections and pins at the computer to make sure they're making good contact.

Now, for your theory that this may have something to do with the injector wiring harness- If you are stalling when the engine warms up and then not restarting until it cools down or maybe even the next day, this may be the culprit. When it you get it running next, give the injector wiring harness a good squeeze and see if it cuts off. If it does, then bingo!

To fix the injector harness, the casing should come apart in two by disconnecting the tabs located on the bottom. Inside you will want to look for a green and orange wire that is junctioned inside of a black rubber-like casing with 6 more wires of its type coming out. To fix it you will need:

Soldering iron w/ solder
Heat shrink wrap
Lighter
Wire strippers
Electrical tape
Knife

To start, simply take your knife and cut the black rubber-like casing from around the wires and discard. Next, you'll want to pull the wires apart and strip them to remove the glue-like substance that previously attached them. The next part depends on how good of a soldering iron you have. Start by cutting a section of your heat shrink wrap and slipping it over the wires, moving it down some to avoid the heat from the iron. I started by taking 2 wires and soldering them together, then adding one at a time until I eventually had them all soldered together, then slid the heat shrink wrap up and used my lighter to seal the connection. Afterwards, wrap the group of wires up in electrical tape and pack them back in to the casing.

Happy Trails! :tank:

Hopefully this solves your problem :cheers:

You need to put away the parts cannon and start TESTING.

"parts cannon" LOL.

Saw it on another thread. Stole it. :D

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