any sponsors or people up north that can check out my tune?
 

I've had a high idle for 6 months, basically just hangs as the rpm's drop. P0507. Here is what I've tried:

-swapped throttle body
-spray brake cleaner looking for vacuum leaks
-visually check for vacuum leaks
-replace entire PCV system (for several reasons)
-completely plug off PCV system
-completely plug off HVAC lines to intake
-replace IAC motor (twice)
-replace TPS
-reset TPS
-remove, inspect gaskets, reinstall intake manifold torquing to spec (had to replace knock sensors)
-swap MAF
-running it on speed density
-disconnected battery for 20 minutes to reset computer
-replaced o2 sensors
-capped off EVAP system at the intake
-swapped on ls6 intake manifold with all new gaskets
-replace intake to brake booster hose
-zip tied MAP sensors in nice and tight

any ideas?

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UPDATE (6/2/11): got HPtuners and took a look at my tune, looks like when I had it flashed to a 6 speed tune they went back and put some of my original tune back on from when it was auto so it's a half and half a4/m6 tune, also found some other oddities but I don't know enough to comment on why it would be that way

1. target idle on stock m6 tune showed 0's across all P/N board whereas mine is all filled in as if it were automatic (seems like stock auto idle settings, but calibration details recognizes my car as 6 speed)

2. MAF frequency at one point dips down and then rises back up, I've read it should never do this since an increase in air should never cause a drop in frequency

3. Main spark advance for the most part has a few degrees pulled throughout most of the High Octane table in my tune vs the stock tune

4. M6 Spark smoothing is disabled on mine but enabled on stock (probably still auto settings)

5. Throttle follower table is basically completely flipped on mine vs. the stock tune, again thinking it's an a4 still when it's now an m6


Screen Shot:
http://i56.tinypic.com/fbkiuf.jpg

soooo I flashed it to an entirely stock 6 speed tune and tuned out my emissions codes and whatnot, we'll see if that fixes everything

stock throttle body?

ported stocker, didn't idle high for the first two years though but I tried swapping in a different one anyway with no change

and it's more of a hanging idle than a high idle, when I rev in neutral it shoots up and then hangs at a few spots on it's way down for wayyy too long

Sounds vacuum related. You seem to have done a good bit of checks already that I would check out.

When you 'reset' the ECU, was there ANY IMMEDIATE difference? trying to see if ECU is bad, although the LS units are pretty good.

Also, O2 sensors good/ working? - I have seen them send odd data to ECU and cause weird occurrences.

I was wondering if o2's could be related since I've gotten o2 codes randomly, maybe once a year since I started screwing with exhaust and whatnot. I was told by a few people they would have no effect on the idle but I have no idea what sensors send data where and how the computer uses that data. I'll try swapping in a lower mileage set (I think I have some somewhere) and see if it makes any difference

ahh ok i had a prob with an aftermarket TB on my TA... my vettes curently got codes for both rear o2's and they arent affecting anything.

hmm yeah the rear o2's are tuned completely out on my car, the fronts have more to do with the tuning from the little that I know so it probably won't have much effect except for the code I wouldn't think

okay swapped out the o2's, thought it helped but after a few minutes of driving same thing

it really doesn't idle too high, it just hangs when the rpm's are dropping for way too long

I also capped off the EVAP system at the intake, and it seemed like it helped for a a few minutes of driving but when I got back home and revved it still hung forever at 1200rpm, dropped a tad, and then hung again before dropping to a normal idle

this is really beginning to bother me

Not directly applicable to your car, but this happens when the advance weights stick in older vehicles. Granted you dont have that, but food for thought. Can you hook up via laptop and see if your timing is changing/ 'hanging up'?

I don't have any software that will allow me to see what's going on, I was hoping someone locally would be able to check it out for a few bucks

installed ls6 intake this morning, zip tied the MAP sensor down good and tight since it was loose (normal, but it bothered me), all new gaskets, seated well, new intake to booster hose and fitting

we'll see if there's any change today

I am not to sure on the LS motors but is the TPS adjustable, can u change the voltage going through it or the angle.

I forget the procedure but I reset it a few times and on a scanner the throttle position reads 0 at closed and follows consistently when I drive

Since you can duplicate the problem sitting still it should be easy to find by someone with the right tools who knows what to look for. If it just started the last 6 months but was fine before then I doubt its in the tune, any time a car I've tuned started running a little off its been something electrical or mechanical going bad - sometimes you can tune around the problem for a while but in the end it should be found and fixed. Who did your initial tune? Maybe they can datalog whats going and give you a direction to go on cause changing parts blindly sucks.

-Steve

I really haven't put any money into the problem yet, I got the intake for $50 with new gaskets and the whole PCV system for $20 because mine was full of oil buildup and the Y piece was tearing. The rest of the parts I had laying around already.

TTP did my tune, but they're gone now. the problem actually started right after my 6 speed swap and having it flashed to a 6 speed tune (they had originally tuned it when it was auto also). I ordered HPtuners so I'll try to post some info on my tune. I had them flash it to a 6 speed tune and then asked if they could put the engine tuning back on it but I'm not sure if they did or if I'm still on a stock tune just with AIR/EGR/o2's/CAGS etc deleted

its something in the tune....

IMO, it's something to do with the auto/6-speed swap in the tune. I know I had similar issues with my Monte with the idle hanging up until I swapped in a prom burned for a 5-speed car. The "throttle follower" probably still needs adjustment in the tune; sounds like it's keeping the IAC motor held open longer than it needs to be, which causes the high idle.

hopefully my HPtuners will be here tomorrow, I'm going to try to download a stock 6 speed .bin and compare the idle tables with mine

updated the original post with some findings if anyone is following this

The guy who wrote LS1Edit lives in Morristown, and for $50 he re-flashed my PCM completely using a Tech 2000 bench setup. Complete new binary image including the operating system. If you're at all uncertain about the contents of your flash, this might be a good next step.

pcmdoc@surfree.net was his email address last time I used it.

I flashed it to a stock tune now and everything has been good so far so I'm happy for now but thanks for the input

Awesome man, glad it's running good now! I had a feeling it was something in the tune since I had BTDT with the Monte.