Ok, my car's now been in the garage 5 times for the same problem...

[hanselthecaretaker]

I have a jeep zj, which is a soldier, but it's sick.

Ever since last summer, when I start it up cold, it will occasionally stall, and in the last few months it has gotten worse, like being very hard to get started again. It now will even get to the point where I'll start it and rev it to keep it running but it will just wind down and stall again, even backfiring a little. I also smell fuel mixture when it starts up again. It also stalls when it's idling or at low rpms, like pulling away at a stop light. I tell each of the three different garages I've broughten it to the symptoms, but they seem to ignore them because they don't know how to do anything without their precious computer and codes. The first time I'd brought it in was November, and pretty much once a month after that. No one can figure out what might be wrong with it, since it acts up very sparatically, and I don't have the time to have it sit in a garage, waiting for their computer to catch the problem.

Cap and rotor, ignition coil, plug wires, and battery have been replaced, and the throttle body has been cleaned. I'm thinking it's gotta be fuel delivery or something, but that whole assembly is like $600 parts and labor.

It's frustrating because it's only problematic in the first few minutes of running. When it's completely warmed up it runs fine, like on longer trips.


The problem better fucking be found this time.




It's a jeep thing........

 

[Buddy_Christ]

What year? Miles?

Have you checked the fuel filter?

 

[hanselthecaretaker]

What year? Miles?

Have you checked the fuel filter?

It's a 98 with 127k or so miles. the fuel filter could be it, but wouldn't it cause more constant problems than just when it's warming up?

 

[USMC fighter]

if its carburated try tighting the idle screw

 

[Buddy_Christ]

It's a 98 with 127k or so miles. the fuel filter could be it, but wouldn't it cause more constant problems than just when it's warming up?

Fuel filter is just a normal part of a tune up. Ever had one get clogged? Not fun to deal with. Bitch will stall like hell under strain. Had one get clogged in an old chevy and it sometimes wouldn't bog at all. If it's stalling/bogging all the time, then it's worth checking out.

You could have cracked vaccum lines, always a possibility.

Considering the year and the fact that it's doing this when cold and coming off idle, I would think the computer is having a problem putting the car into "open loop." That's where the fuel flow goes back to when you are not pressing on the gas or the car is warming up, you could consider it to be "high idle." This might not be the correct answer, but it sounds like it could be the problem.

Does it only do this when cold? Does it do the bogging/stalling when it's warm and you are coming off of a stop sign?

Can you take it to the dealer or is that where you have been taking it?

If I had this car in front of me and was sitting in a dealership with unlimited parts at my disposal to test with, I'd grab a computer for the exact same make/model (including the same trans, makes a difference), plug it in, and see if it gives the same issue.

You could try resetting the computer. The computer might have picked up something weird along the way that's not letting it go into open loop correctly. That's as simple as popping the hood (or could be under the dash, I havn't messed with Jeeps, but a lot of newer cars have 2 fuse boxes, one under hood, one under dash) and finding the underhood fuse box, then pulling the fuse for the ECM. If you can't find that, you could always disconnect the battery for a few minutes. That works as well, but pulling a fuse is so much simpler.

 

[hanselthecaretaker]

if its carburated try tighting the idle screw

It's FI, but is it possible that the timing is off a little? It seems to idle well, although the engine rpms dip a little at first when I put it from neutral into drive at a drivethru.

 

[hanselthecaretaker]

Fuel filter is just a normal part of a tune up. Ever had one get clogged? Not fun to deal with. Bitch will stall like hell under strain. Had one get clogged in an old chevy and it sometimes wouldn't bog at all. If it's stalling/bogging all the time, then it's worth checking out.

You could have cracked vaccum lines, always a possibility.

Considering the year and the fact that it's doing this when cold and coming off idle, I would think the computer is having a problem putting the car into "open loop." That's where the fuel flow goes back to when you are not pressing on the gas or the car is warming up, you could consider it to be "high idle." This might not be the correct answer, but it sounds like it could be the problem.

Does it only do this when cold? Does it do the bogging/stalling when it's warm and you are coming off of a stop sign?

Can you take it to the dealer or is that where you have been taking it?

If I had this car in front of me and was sitting in a dealership with unlimited parts at my disposal to test with, I'd grab a computer for the exact same make/model (including the same trans, makes a difference), plug it in, and see if it gives the same issue.

You could try resetting the computer. The computer might have picked up something weird along the way that's not letting it go into open loop correctly. That's as simple as popping the hood (or could be under the dash, I havn't messed with Jeeps, but a lot of newer cars have 2 fuse boxes, one under hood, one under dash) and finding the underhood fuse box, then pulling the fuse for the ECM. If you can't find that, you could always disconnect the battery for a few minutes. That works as well, but pulling a fuse is so much simpler.

Must spread karma.....

thanks, I've probably reset the computer when I had to put a new battery in.

I only have the problem when it hasn't been running long. After I've been on the highway for 15-20 minutes it hasn't acted up yet (knock on wood).
And it's still got balls too, enough to throw me back in my seat at midrange in town when I punch it.

What you've said about "open loop" is a great possibility......something sticking until all the parts are warmed up. But it doesn't consistently stall...sometimes I can go a week w/o any problems, and other times it could happen 2-3 days in a row.

 

[Buddy_Christ]

Must spread karma.....

thanks, I've probably reset the computer when I had to put a new battery in.

I only have the problem when it hasn't been running long. After I've been on the highway for 15-20 minutes it hasn't acted up yet (knock on wood).
And it's still got balls too, enough to throw me back in my seat at midrange in town when I punch it.

What you've said about "open loop" is a great possibility......something sticking until all the parts are warmed up. But it doesn't consistently stall...sometimes I can go a week w/o any problems, and other times it could happen 2-3 days in a row.

Ah yes, the elusive Jeep electrical problems

It's not really something "sticking" as it is the computer sending a bad message or recieving a bad signal, but it isn't bad enough for the computer to throw a code. Follow me?

What's the weather like when it does this? Lots of rain? High humidty? What?

 

[hanselthecaretaker]

Ah yes, the elusive Jeep electrical problems

It's not really something "sticking" as it is the computer sending a bad message or recieving a bad signal, but it isn't bad enough for the computer to throw a code. Follow me?

What's the weather like when it does this? Lots of rain? High humidty? What?

Any type of weather (warm, cold, freezing) but seems more predominant with moisture/humidity.......electrical=strong possibility. Maybe a crank sensor?

I'm thinking it would be cheaper just to guess and start replacing this stuff.

 

[Buddy_Christ]

Any type of weather (warm, cold, freezing) but seems more predominant with moisture/humidity.......electrical=strong possibility. Maybe a crank sensor?

I'm thinking it would be cheaper just to guess and start replacing this stuff.

Electrical sounds like a strong possibility.

Want to test it yourself? Go grab a spray bottle, fill it with water, start the car, and start misting water everywhere. If it starts giving you issues, well, I think you can figure out what I'm getting at.

This is a more rare one but I've heard of it happening. Sometimes you'll get a minute crack in a spark plug wire and when it's really humid/wet out, it will arc to the block or some other metal, causing a problem. Well, here's the rare one....sometimes you can have an issue in the distributor where instead of the spark going out to the wires, it arcs right down the shaft and into the block. Nice, eh?

Do the spray bottle thing since you said it happens more when it's humid or wet. Don't start yanking and replacing parts, that's just going to cost you more money than it's worth.