What would cause the car to revert back to a crappy idle? I have been reflashing my car w/LS1 edit over the last few months with changes that have been sent to me (email) by the Performance company that dynotuned my car last year. It always seems like the changes make a difference, but then a few days go by and it goes back to the way it was. I have a 225/225 .589/.589 112LSA. Just curious if there has been any similar problems with tuning.

 

No. What have you changed?

 

I forgot to say earlier that it is an automatic.

Changes since dynotune: (5 Edit files)

Moved throttle screw 1 1/2 turns

All Idle Speeds have been increased to at least 925
IAC Park Position values are all above 21
Idle Air Values have been increase above 120C
P/N Airflow Decay was increased by 30% on from 0MPH to 14MPH
VE Table has been increased in the first 3 column's (Don't know by how much)

From what I understand that's the only tables that they change, so I haven't really looked anywhere else.

I compared the latest flash I recieved to NOGO's method on fixing idle issues. The VE tables and High Octane Spark advance tables were also altered very closely to what is recommended. The only difference that was a lesser value was the idle after 132 degrees, it was 925.

 

I hate to say it, but it sounds like your problem is just the tune. You are probably hitting a wall somewhere in how much your PCM can adjust. Most of the changes that you have been sent are standard "chop-shop" PCM tunes. You really need the capability to log some data and see what your PCM is doing. Now when you say your VE was raised...is that what you meant? Higher values? I have seen that before on cars that have cams and lids. It is done to get the trims in line, but your car will still idle like crap. The problem with doing that is that your MAF pulls your trims positive, but your VE is actually too rich anyways. So you end up loading up with fuel, and a crappy idle, even though your trims look ok. But I have still seen "pro" tunes where it was done. Please check and make sure the values were increased and not decreased.

 

I have Autotap, and I've been loging some of the data. The only thing that seems abnormal is how much the advance spark jumps at idle. Varying almost 10 degrees just sitting in park. (may be normal, I don't know) I really don't know exactly what to be looking for. I have EVILive V5. Is there anything that would help me figure this out? I've been logging the "desired IAC" counts. They look good as well. The idle is fine, the problem really only exists when I let off of the throttle (i.e. parking lots, stop lights). It begins slowly surging at 20-25, and then gets worse until I come to a stop. Once I stop, it levels back out quickly.

The main VE Table is the table that I was talking about. (Engine Calibration/Fuel Tab/Main Volumetric Efficiency Button)
My apologies. It was actually decrease.

Stock to Dynotune: x by 65% in column for 400
x by 75% in column for 800
x by 90% in column for 1200

-No changes on first email tune
-Second email tune x by 95% in column for 1200
-No changes on third email tune
-No changes on fourth email tune

The tuner is quite a distance away from me. Being in the Air Force you can't really depend on being somewhere for a while. I'd would be so much easier just driving to see the tuner, but distance has prevented that from happening. I really don't think that this is a second hand shop that has done the work to my car. The tuner has bent over backwards, always returned my calls/emails. I have been very impressed so far with them. I'm just really trying to help in any way I can. Plus it really gives me a chance to learn about this stuff. Really all I want is my car to be as close to normal as it can be.

 

Anyone?