I ran the Jeep today and it seemed to run nicely out of the garage. I only ran it about 1 mile and it started to run REALLY high at idle. I have the datalogs off of it from WinALDL. BLMs and INTs are definitely moving around a little, but not enough to cause it to do THIS. Out of gear, it will hold a rock solid 750 rpm idle. In gear, it bumps a little, but once the engine warms up, it wants to idle at 1300 rpm or more. Could this be related to the P/N switch or a tranny parameter? Maybe a crappy vacuum leak somewhere I haven't looked yet?
TIA, guys!

 

I had 1 that did that.
It was going back into open loop at idle. I had to adjust the TPS% for OL and the OL idle AFR enable(7747) so it would stay in closed loop at idle.
Once I had my VE and idle and timing all tuned it was not a factor.

Not sure if this is what yours is doing but when I first started playing with these I chased the fast idle for a while!!

I also lower the IAC steps for all temps.

 

IAC...Ah HAH!!! Hmmm...that is interesting. It also brings to mind the possibility of a vacuum leak somewhere.
Thank you, Bill. Once again you have bailed my *** out of a hole.
Results in the morning.
The weird thing is that it idles like a champ at first. Then, once I get it out on the road, it wants to idle up like it is overheated or something. I took it out of gear today at the local Circle K and it idled up to 1750 rpm...WTF????

 

I know, like I said I chased my tail for a while. since I don't use the vss i was sure that was it......nope.
tried the pk/n wire....nope.

It ended up just being basic things like the VE and making sure the IAC was adjusted for the lower temp thermostat.
What I found may be different than yours nut it's a place to start.
make sure the IAC count is still moving and above 0 when this is happening. I have had the IAC lock in 1 position.
I have read about the IAC getting confused when you don't run the VSS and may require an IAC reset so it can relearn!!!

 

Make sure the IAC isnt all coked up with carbon and varnish. Sticky IACs dont work well. Also make sure that the steps in the IAC steps vs cool temp table above, say, 50 deg C are less than or equal to the IAC kickdown steps.

 

Thanks guys! I happen to have a freshly cleaned up IAC that I was getting ready to put in my Holley throttle body.
I did the IAC reset a week or so ago. Maybe I need to do it again. My battery WAS a little low then. I haven't even touched the VE yet...just trying to get it to idle right after I put it on the road. It idles beautifully on the driveway after it is warmed up. Maybe I DO need to play with the IAC tables a little.
Thanks again...

 

Just saw this part in the log. Is this indicative of a vacuum leak?
Engine was at 186F...normal operating temp.

 

Yes, if its a mild motor it should only be around 35-40 kpa. Fully seat the IAC and unplug it and start the vehicle again and see if it still only pulls around 12 inHg. Also check to make sure the map is still functional. You can test it with a vacuum pump and gauge. It should coorelate very closely with a mechanical vacuum gauge (provided the map is converted to units of vacuum). After that, find the leak...

 

I think I know where the leak is. If it is where I think it is, I am gonna REALLY feel like a dumbass.
Results in a little while. I have to go get some carb cleaner so I can find the vacuum leak.
What is the conversion from MAP kPa to inches of Hg?

 

the conversion to vacuum in inHg is [29.9 inHg - ((MAP value)/101.1 kPa x 29.9 inHg)] to get the vacuum in inches of mercury.

 

Thank you sir!
I'll go outside in a few minutes and see what I can come up with.

 

Be careful with that carb cleaner! I started a small fire a couple weeks ago when the car I was working on decided to backfire while spraying with carb cleaner to find a vac leak!

 

Found the problem...the TB to manifold gasket was leaking. Carb spray is cool...and I didn't start any fires.
Thanks guys! I think that may have been the source of the problems. I found it today while I was tuning the low VE stuff. It reared its ugly head right after I got the IAC and TPS reset done. I started it up, put it in gear, and the thing couldn't hold a solid idle at all. Talk about surging! I mean 75 rpm surges that were EASILY noticable.
I'll convert the datalogs and post a section in a little while for your perusal and subsequent insults.