Well, it starts again. Tested it in my driveway, started running rougher after being at operating temp, it then stalls out eventually. Starts back up each time with a backfire. So, I'm looking around and stupid me forgot to tell the exhaust man to weld a bung in for my upstream o2. Got to thinking, will lack of the upstream o2 cause it to stall? I figure it sees a constant lean condition and keeps adjusting till it floods. Ill check to make sure it has good fuel pressure. But I'm going to scavange the bung from my jeep exhaust and weld it in and see what hhappens

 

If the sensor is plugged in, that may be part of the problem. If the sensor isn't, it should just set a code, and then run off of tables stored in the PCM.

Might be a failing sensor somewhere too....... once it gets hot, it doesn't work as well as it should. (cam sensor maybe?)

 

Ill try unplugging it and see what happens. The cam sensor is new, which new doesn't always mean good I suppose. I really just wanna drive this jeep and enjoy it! Haha

Well tried it with the o2 unplugged, stalled out quicker, plugged it back in and it ran for longer. If I tapped the gas or gave it any throttle it would stall as the rpms dropped. And to go along with this problem, the started is now acting up, not engaging the flywheel everyother start up.

 

I'm set now that's its the cam or crank sensor. Stalled and wouldn't start and checked for sparkand it sparked randomly. Stopping by the dealership tomorrow for both.

 

So, started my new job this week so I haven't had much time to mess with the Jeep. But so far I've replaced the crank and cam sensor with factory replacements, got the o2 sensor hooked up and in the exhaust now. The motor runs a little better, but still stalls. It doesn't stall as much but still does it. I thought it was just at idle, but today I had it at quarter throttle in my driveway and it stalled. I've cleaned the iac and the passage in the throttle body, no change. I did notice that the plenum gasket is bad, oil had coated the intake. What else would I be looking at here that would cause it to stall?? Map, tps? I know on my jeep a bad tps would just have it idle all over the place but never once did it stall, and the tps was bad for over a year. Would a leaky plenum gasket cause these problems? After all the new parts and cleaning its stalled maybe 3 times. But has attempted to stall about 10 times. Also, sometimes when its idling and I tap the throttle I hear a pop in the exhaust like a mini backfire. Which it hasn't backfired yet after starting it after it has stalled.
I wish I could get it hooked to a computer but I live to far out and I'm nervous about being stuck on the side of the road again, plus its like $80 to hook it just to a computer.

 

Wonder if you are having fuel sync issues....... (the timing for just when the injectors fire).

You can test the tps...... just need a decent meter. (preferably analog.)

Being able to see the data stream while it is acting up would be nice.......

What is fuel pressure doing when it stalls? Inadequate fuel supply (volume, not necessarily pressure) would give you the same symptoms. (especially the part throttle stall.)

 

Backfiring in the intake makes me think the injectors are firing too early. But that shouldn't effect out that bad, unless it was really out.

You ever had the distributor out?

Also, a summary of what you've replaced would be nice, I tried reading through the thread, but I'm not sure what pcm you are currently running, or what sensors have been replaced.

 

I'm not sure on the fuel pressure. I noticed I do have a fuel leak at the hard line. The exhaust shop disconnected it and forgot to clip it in all the way, or tried and couldn't, but I am now missing an o ring there. It leaks alot when its not running, but while its running it barely leaks, like a drop every 5 minutes.
Isn't timing controlled by the pcm? Could it be a streched chain, or it jumped teeth? But it would run bad all the time right? Ill probably find a fuel pressure gauge next week, I think my buddy has one he's not using.

 

Fix the fuel leak before you die.

 

I'm running a 96 pcm from an auto, I've replaced the crank and cam sensor with factory parts, new upstream o2 sensor, have new rotor, cap, and wires as well. I've never had the distributor out. I've cleaned the iac as well.
I'm going to napa tomorrow and getting the missing o ring.