HELP! Stalling Issue
 

I have a 94 ZJ with the 5.2 and when I drive it and let off of the gas the jeep stalls out, when this happens it also doesnt want to restart. I can crank it over but it will not start. If I let it sit 30 minutes to an hour it will start up just fine. I am at a complete loss here and would prefer to not lose my Jeep because of this issue but I cannot have a vehicle that isn't reliable and that is sadly what the Jeep is becoming.

Any help is appreciated, have been told it sounds like a fuel pump but would like to here from those who also have Grands and may have had a similar issue

I havent solved mine but im back to the #2)

1) Do a proper tune-up: Oil change, Spark Plugs, Plug Wires, Air Filter, etc. Check for blown fuses.
2) Go to junkyard and buy about 3-4 ECMs. Replace each one of these until your truck works. If it doesnt work:
3) Leave a new ECM installed and change the Crank Position Sensor. If it doesn't work:
4) Change the Distributor and with it the Camshaft Position Sensor. If it doesn't work:
5) Change the MAP Sensor, Idle Air Controller and Air Intake Temperature Sensor. If that doesnt work:
6) Change the Throttle Position Sensor. If that doesnt work:
7) refer back to #2

At this point I think I bought a really expensive ECM and it didnt work out of the box. However, I purchased it from a seedy retailer that I dont want to do business with again so I am going the junkyard route.

Griffin, check your CPS for a pulse signal, or just replace it. The symptoms you describe are typical of a failing CPS. DO NOT replace the PCM until you verify a good CPS signal. Without this signal, the PCM will not allow a start.

or do that. He knows more than me as my Jeep is still sitting in that parking space dead. =(

I hate to have guys shotgun parts at a vehicle when a few circuit and signal checks can save money and frustration. Check your fuel pressure while it's running and after it dies. If it's holding pressure but won't start, your fuel pump is NOT to blame. The CPS likes to quit when it gets warm and after a cooldown, starts working again. You can back-probe the connector with a pin and an analog voltmeter to see if you're getting a pulse signal. One wire is 12V supply and the other is a pulse signal as the engine turns, best tested while cranking.

For what it is worth I wasn't suggesting shotgunning, but a series of replacements one after another which were perhaps not in the right order. I would say more of a... Browning approach, perhaps?

In attempting to solve this issue on my Jeep I took the same steps I suggested, except I did them in a different order. I performed major tune up then changed everything that made sense for the troubleshooting, especially with a Haynes manual and you guys here on this forum. I ended up with doing the PCM/ECU last because it was such an expensive part and sad because I apparently have to change this NEW one and there isnt such a thing as a new PCM/ECU.

This issue is really only due to an exclusive 5 or 6 problems, and what it comes down to is a 50/50 change of succeeding by changing the Crank Position Sensor and the PCM/ECU, and troubleshooting through them.

Aside from that, I can support a shotgun method of replacing every one of your sensors with premium MOPAR replacement parts brand spanking new if you can afford it so at least you know you have 200k+ on them and anythign else that breaks shouldn't be those! Haha then its definitely time to get out the Ohmmeter if one of the sensors goes bad before "it's time."

I apologize.

No problem Auger. I flew off the handle because so many guys DO replace a bunch of expensive parts only to find they have a broken wire or something simple. I heartily agree with using only Mopar for sensors because quality of construction is critical and most aftermarket suppliers don't spend the time and money necessary to make a quality part, especially if they are made overseas.

One thing I discovered that annoys me is in 2002 and up, the oil pressure sensor is just on or off. It doesn't read actually pressure! WTF?

Thanks everyone for your help, I ended up selling the ZJ. It needed more work than it was worth in the end(found out it needed new front axle as well), ended up buying a 96 ZJ from my dad in much better shape and lifted.