Idle Relearn Procedure for an LS2 GTO? Can't get the car to not IDLE HIGH.
02-25-2014, 01:02 PM
#1
Staging Lane
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Idle Relearn Procedure for an LS2 GTO? Can't get the car to not IDLE HIGH. My Previous thread....
Anyone have this info from GM? Or do you need a Tech 2 to accomplish this? I've tried the relearn procedure where you idle the car in park with and without the A/C and that doesn't work.
I put on a NEW Throttle Body and my car is idling high (around 1200-1400 rpm) and i'm getting PO507. And no I do not have any vacuum leaks! If I borrow another throttle body from a friends the car and install it, the car idles and runs fine. I've tried 2 different TBs and both have the same issue and both can't possibly be bad. Theres got to be something with learning somewhere.
Any input? Thanks.
Anyone have this info from GM? Or do you need a Tech 2 to accomplish this? I've tried the relearn procedure where you idle the car in park with and without the A/C and that doesn't work.
I put on a NEW Throttle Body and my car is idling high (around 1200-1400 rpm) and i'm getting PO507. And no I do not have any vacuum leaks! If I borrow another throttle body from a friends the car and install it, the car idles and runs fine. I've tried 2 different TBs and both have the same issue and both can't possibly be bad. Theres got to be something with learning somewhere.
Any input? Thanks.
02-25-2014, 09:29 PM
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Staging Lane
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The car was fine before I messed with it as far as I know...
I decided the other evening to clean the MAF sensor and the TB on my GTO with CRC MAF cleaner (used this stuff for years on several cars with no issues. Plus my DD had an issue last week and cleaning it did wonders). I did this to the GTO and let the MAF properly dry and I sprayed the TB and blade (had someone hold open the TB by holding the pedal) and wiped it out the best I could.
After doing this I started the car (which took a little throttle effort which I expected (since I know some cleaner got in the intake and needed to be burnt off). It seemed to idle maybe a couple hundred RPMS more than normal. Then I notice my headers on cylinder primary 5 was bright red and 7 was starting to turn red. I ended up getting that PO507 code. I quit for the night and messed with it tonight. I checked all the plugs and they read all the same but I know I have a lean condition on 5 and 7. I went ahead and cleared the code and ran the car again. I noticed a slightly higher idle and the primaries were glowing again. I sprayed carb cleaner on the tb connectors to check for vac leaks and didn't notice any noticeable change (the car is cammed btw). Now I'm stuck with what to do now. I went to do a simple task and here I am now. I looked up PO507 on the internet and several people have replaced IACs and EVAP purges with no luck. Several others had vacuum leaks that needed to be fixed (which I'm sure I don't have). One person even mentioned a MAF problem which I'm wondering if this couldn't possibly be my issue?
Hoping someone here has had a similar senerio and can possibly lead me in the right direction. I'm starting to think the MAF since after messing with it everything went to hell.
Appreciate any help, thanks....
I decided the other evening to clean the MAF sensor and the TB on my GTO with CRC MAF cleaner (used this stuff for years on several cars with no issues. Plus my DD had an issue last week and cleaning it did wonders). I did this to the GTO and let the MAF properly dry and I sprayed the TB and blade (had someone hold open the TB by holding the pedal) and wiped it out the best I could.
After doing this I started the car (which took a little throttle effort which I expected (since I know some cleaner got in the intake and needed to be burnt off). It seemed to idle maybe a couple hundred RPMS more than normal. Then I notice my headers on cylinder primary 5 was bright red and 7 was starting to turn red. I ended up getting that PO507 code. I quit for the night and messed with it tonight. I checked all the plugs and they read all the same but I know I have a lean condition on 5 and 7. I went ahead and cleared the code and ran the car again. I noticed a slightly higher idle and the primaries were glowing again. I sprayed carb cleaner on the tb connectors to check for vac leaks and didn't notice any noticeable change (the car is cammed btw). Now I'm stuck with what to do now. I went to do a simple task and here I am now. I looked up PO507 on the internet and several people have replaced IACs and EVAP purges with no luck. Several others had vacuum leaks that needed to be fixed (which I'm sure I don't have). One person even mentioned a MAF problem which I'm wondering if this couldn't possibly be my issue?
Hoping someone here has had a similar senerio and can possibly lead me in the right direction. I'm starting to think the MAF since after messing with it everything went to hell.
Appreciate any help, thanks....
Did the idle relearn, didnt notice any difference and the code came back. Sprayed around looking for vacuum leaks with little luck. Im wondering if the vent hose that connects on the Vararam coupler could have a slight leak... Im going to change that up (planned on it anyway, never liked it) and see what happens. Hoping its that easy but im not getting my hopes up yet. Ill report back soon.
Alright I borrowed my TBSS MAF and saw no difference. I seal up the vent tube better on the coupler and still no different.
Still idling high and I'm still getting PO507 and still have red glowing headers. I'm kinda stumped. Any other ideas?
Still idling high and I'm still getting PO507 and still have red glowing headers. I'm kinda stumped. Any other ideas?
I used some rubber hoses and replace the EVAP line to the intake. Replaced the valet cover hose to intake like with new. I even at one point bypassed the EVAP
(by putting a nipple on the intake) and still no change and po507 comes back.
(by putting a nipple on the intake) and still no change and po507 comes back.
To summarized I cleaned my TB and MAF with CRC MAF cleaner like I have done with many of my cars over the years. I had my wife actuate the throttle while I sprayed and cleaned. I DID NOT move the throttle blade by hand, I heard this screws them up on DBW cars. I figured I must of somehow damaged the sensor in the TB by cleaning it. (which I don't know how in the hell that could of happened since I've done the LS2 in my TB SS, the L92 in my Denali, and the LY7 in my G8 without ANY issues what so ever). After extensive diagnosis (see above), I borrowed a friends 100k mile LS2 TB, the car ran fine, no codes, even drove it around.
So after thinking I solved the problem, I purchased a Ported TB and I had the same issue as soon as I put it on! To make sure I wasn't crazy again, I borrowed that 100K TB and and again, same thing. Car ran great.
Since the TB was a ported core I though maybe I have really crappy luck and got another bad TB. So I said screw it, I'm not getting screwed again, I'm buying a brand new AC/Delco OEM GM TB! As soon as I put it on, guess what??? It ran like crap again!!! Something does not make sense here.
Last edited by Iron Indian; 02-25-2014 at 09:51 PM.
02-26-2014, 01:32 PM
#5
Can you post your tune? First you said a borrowed a TB from a friend it fixed the high idle, then you also said that a new stock TB made it run like crap.
If the headers are glowing at idle, that means the PCM is retarding the spark timing to try to lower the idle RPM. I would lower the min idle airflow in the tune. I spray water to locate vacuum leaks, never carb spray. Spraying water on a vacuum leak will cause the engine to run rough, were as carb spray won't.
Russ Kemp
If the headers are glowing at idle, that means the PCM is retarding the spark timing to try to lower the idle RPM. I would lower the min idle airflow in the tune. I spray water to locate vacuum leaks, never carb spray. Spraying water on a vacuum leak will cause the engine to run rough, were as carb spray won't.
Russ Kemp
02-26-2014, 11:03 PM
#6
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I tried posting my tune, file was too big to upload. I can e-mail it directly to you if you'd like, its an HPT file. Let me know.
Yeah I figured timing was retarded a bit for the glowing headers.
I might try lowering that min idle air flow. Though I don't know much on how to mess with it. I usually have to pay to have tunes done, I'm not handy with an HPT at all nor do I trust myself.
I'll have to try the water trick. Only way I've ever found vacuum leaks on cars previously was carb cleaner or brake cleaner. (that can be too harsh though) Like I said, I'm about 99% sure I do not have a vacuum leak.
Thanks for your time and help!
Yeah I figured timing was retarded a bit for the glowing headers.
I might try lowering that min idle air flow. Though I don't know much on how to mess with it. I usually have to pay to have tunes done, I'm not handy with an HPT at all nor do I trust myself.
I'll have to try the water trick. Only way I've ever found vacuum leaks on cars previously was carb cleaner or brake cleaner. (that can be too harsh though) Like I said, I'm about 99% sure I do not have a vacuum leak.
Thanks for your time and help!
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02-26-2014, 11:21 PM
#8
For some reason using carb cleaner to check for a vacuum leak doesn't work very well on an engine with a plastic manifold. Why I don't know, it's just been my experience. The "best" way IMO is when spraying carb cleaner watch your STFT's and your 02 sensors. If you do have a vacuum leak when you spray over it your STFT will go negative and your 02 will max out towards the rich side.
FWIW, I had a 08 Denali at work a few weeks back that I cleaned the TB and MAF on. I did the relearn procedure correctly as per GM but I never could get it to work. I ended up using the Snap On scanner and it fixed it immediately.
What's your IAC count, TPS voltage, etc?
I thought I remember reading that somewhere in HPT there is an idle relearn procedure but I'm not 100% on that.
Let us know what you find out.
FWIW, I had a 08 Denali at work a few weeks back that I cleaned the TB and MAF on. I did the relearn procedure correctly as per GM but I never could get it to work. I ended up using the Snap On scanner and it fixed it immediately.
What's your IAC count, TPS voltage, etc?
I thought I remember reading that somewhere in HPT there is an idle relearn procedure but I'm not 100% on that.
Let us know what you find out.
