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-   -   Replaced IAC motor... Still stalling (http://www.jeepgarage.org/f203/replaced-iac-motor-still-stalling-41875.html)

tkdgirl 05-08-2012 04:28 PM

Replaced IAC motor... Still stalling
 
Had a p0505 last week and replaced the IAC motor (and o2 sensors too). Ran great for a few days and today, started stalling at idle again. What gives?

Should note I left cabin lights on and battery died this weekend. Jumped it back...

Frango100 05-08-2012 05:02 PM

Re: Replaced IAC motor... Still stalling
 
No check engine light on or any fault code set now? Is the problem exactly the same as before changing the IAC motor? Did the problem imediately start after draining the battery?

tkdgirl 05-08-2012 05:15 PM

Re: Replaced IAC motor... Still stalling
 
Here's the sequence of events (LOL!)

- Last Tuesday, engine light comes on on start up. Checked pcode and got p0505. Jeep stalled at ever stop on the way home.
- Last Thursday, installed new O2 sensors.
- Last Friday morning, had new IAC motor put in.
- Last Friday evening, left for our of town and Jeep ran great.
- Sat. night left cabin lights on all day and drained battery. Jumped and was fine.
- Returned home on Sunday evening, everything was fine.
- Today, stalling began on way home from work. I think it began after turning the AC on. So I tested the engine with the AC off- no stall but very rough and low idle on stop.

ETA: In the past 10 months I've had a new fuel filter, new TPS, new plugs, new o2 sensors and new IAC motor.

Frango100 05-08-2012 05:56 PM

Re: Replaced IAC motor... Still stalling
 
But did you check for an eventually fault code set? I would have a look at the IAC stepper motor connector if its completely locked.
And you could try a complete reset, disconnecting the battery one more time for a few minutes and see how it goes.
And if this doesnīt help, its maybe a good idea to check with a scanner with live data the TPS position at idle to be stable. I donīt know for the 4.0, but on my 4.7 its around 12 % in idle.
And when you changed the IAC stepper motor, was the IAC air canal checked and cleaned as well? A lot of oil residue will form overhere and gradually close the opening, causing rough and unstable idle. As you mentioned that it seemed to be starting when switching the AC on, at that point the IAC stepper motor is commanded to open a bit more, to compensate for the higher load from the AC compressor.

tkdgirl 05-08-2012 06:46 PM

Re: Replaced IAC motor... Still stalling
 
Quote:

Originally Posted by Frango100 (Post 626685)
But did you check for an eventually fault code set? I would have a look at the IAC stepper motor connector if its completely locked.
And you could try a complete reset, disconnecting the battery one more time for a few minutes and see how it goes.
And if this doesnīt help, its maybe a good idea to check with a scanner with live data the TPS position at idle to be stable. I donīt know for the 4.0, but on my 4.7 its around 12 % in idle.
And when you changed the IAC stepper motor, was the IAC air canal checked and cleaned as well? A lot of oil residue will form overhere and gradually close the opening, causing rough and unstable idle. As you mentioned that it seemed to be starting when switching the AC on, at that point the IAC stepper motor is commanded to open a bit more, to compensate for the higher load from the AC compressor.

All good tips. It's going in on Friday for another look-see.

tkdgirl 05-14-2012 08:32 AM

Re: Replaced IAC motor... Still stalling
 
Cracked intake gaskets. New one being installed now.

tkdgirl 05-20-2012 07:22 PM

Re: Replaced IAC motor... Still stalling
 
Well, the new intake gasket didn't completely fix the problem. Still very unstable idle with a lot of sputtering and almost stalls. The RPMs fluctuate from around 500-1200.

So could it be a bad PCM?

Frango100 05-25-2012 07:43 PM

Re: Replaced IAC motor... Still stalling
 
No fault codes shown anymore? Where all lines and hoses connected properly? Sounds as some vacuum leak somewhere.


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