06' canyon idle issues (from ported tb)

[gixxr750]

ok fellers here it is... wonderin if there can be a possible correction for a problem i'm having. I recently ported the inlet side of my throttle body on my 06' gmc canyon and managed to port a bit from where the butterfly seals and now i'm having problems with my idle.

the truck idles at 1100 rpm in neutral and i have the target idle set to 750. i was getting a code for high idle and the truck would sputter pretty bad when the dtc came up. i then unchecked the MIL light for high idle and cleared my DTC's but it would keep throwing the code and start sputtering except without the MIL light. i was finally able to get the code from coming up by setting the max and max fail under idle airflow both to 0. the truck still idles high, but no more code or sputtering. i'm wondering if i can get some feedback on this. i was thinking if being able to close the butterfly a bit would help with the idle, but i dont see any settings that allow you to adjust this. as it is i understand this is something i goofed up on when porting, but overall other then the idle issue i'm pretty happy with the results of the mod. HPtuner is the only thing i can think of that might help compensate for this... any thoughts? thanks in advance!

[redhotjamedjimi]

theres no replacement for displacement. Theres nothing the pcm can do about too much air/hp whens its running purely on stoich. only way id see is a custom fabbed plenum. also changing your idle ve wouldnt hurt.

[ChevyHighPerformance]

Depending on how much you opened up the area, you can try "squishing" the butterfly. Remove the TB and hold the butteryfly at its 90 degree position. Hold the TB up to the light and see where you gaps are and mark the butteryfly where the gaps are. Remove the butterfly and put it on a smooth firm steel surface. Gently tap (very gently) with a hammer on the rim of the butterfly in the locations that need to be "longer" (flip the butterfly and do this from both sides). As you hammer the material it will thin out and expand to fill the gap based on its poisson's ratio. Do this very slowly - it will take many iterations so dedicate some time. You may have to do some grinding on the edge of the rim to make the butterlfy circular again. This is sort of an art and its tough to explain in words.

[gixxr750]

thanks for this idea it sounds like it would work. i follow what your saying, it will take patience and a steady hand sort of like porting. good thing i have a spare worse comes to worse. its a shame the position of the butterfly can't be adjusted though. i think if i could've been, the high idle might be corrected...

[marky_24]

have you tried to turn you idle down with the scanner? to see if it can be done with out fixing your tb

[gixxr750]

have you tried to turn you idle down with the scanner? to see if it can be done with out fixing your tb

yes, it wont go down...

[turboLS2]

I had this same problem today after I put a ported TB on my 08' Trailblazer SS, but it was both in the sense of a high idle at startup and also having the car wanting to drive itself down the road after you take your foot off the gas. The TB is ported big time ALL the way and even though no air is getting by the blade when it is closed it never closes all the way with the stock settings in the tune.

I had really good luck eliminating the problem by doing two things:

Under Engine--> Idle --> Idle Airflow--> Startup Airflow I multiplied the entire table by .75 which solved my high idle startup issues

then...

Under Engine--> Idle --> Idle Airflow--> Airflow Final Minimum I reduced all the values up to 3500 significantly for every gear including P, N, and R. I tried these values below first but the truck wanted to slow down a little too much when I let off the gas driving down the road:

4.00000 4.00000 4.00000 4.00000 4.00000 4.00000 6.00000 8.00000 10.00000 12.00000 16.00000 20.00000 20.00000 20.00000 20.00000 20.00000 20.00000
4.00000 4.00000 4.00000 4.00000 4.00000 4.00000 6.00000 8.00000 10.00000 12.00000 18.00000 22.00000 22.00000 22.00000 22.00000 22.00000 22.00000
4.00000 4.00000 4.00000 4.00000 4.00000 4.00000 6.00000 8.00000 10.00000 12.00000 17.00000 21.00000 21.00000 21.00000 21.00000 21.00000 21.00000
4.00000 4.00000 4.00000 4.00000 4.00000 4.00000 6.00000 8.00000 10.00000 12.00000 14.00000 18.00000 18.00000 18.00000 18.00000 18.00000 18.00000
4.00000 4.00000 4.00000 4.00000 4.00000 4.00000 4.00000 8.00000 10.00000 12.00000 14.00000 18.00000 18.00000 18.00000 18.00000 18.00000 18.00000
4.00000 4.00000 4.00000 4.00000 4.00000 4.00000 7.19922 8.00000 10.00000 12.00000 14.00000 18.00000 18.00000 18.00000 18.00000 18.00000 18.00000
2.80078 2.80078 2.80078 2.80078 3.00000 4.00000 5.00000 6.00000 7.00000 8.00000 10.00000 12.00000 12.00000 12.00000 12.00000 12.00000 12.00000
4.00000 4.00000 4.00000 4.00000 4.50000 5.50000 6.50000 8.00000 10.00000 12.00000 19.00000 23.00000 23.00000 23.00000 23.00000 23.00000 23.00000
2.80078 2.80078 2.80078 3.00000 4.00000 5.00000 6.00000 7.00000 8.00000 8.00000 10.00000 12.00000 12.00000 12.00000 12.00000 12.00000 12.00000

So now I am going to try these for a happy medium:

4.00000 4.00000 4.00000 4.00000 5.00000 6.00000 8.00000 10.00000 12.00000 14.00000 18.00000 18.00000 18.00000 18.00000 18.00000 18.00000 18.00000
4.00000 4.00000 4.00000 4.00000 5.00000 6.00000 8.00000 10.00000 12.00000 14.00000 20.00000 20.00000 20.00000 20.00000 20.00000 20.00000 20.00000
4.00000 4.00000 4.00000 4.00000 5.00000 6.00000 8.00000 10.00000 12.00000 14.00000 19.00000 19.00000 19.00000 19.00000 19.00000 19.00000 19.00000
4.00000 4.00000 4.00000 4.00000 5.00000 6.00000 8.00000 10.00000 12.00000 14.00000 16.00000 16.00000 16.00000 16.00000 16.00000 16.00000 16.00000
4.00000 4.00000 4.00000 4.00000 5.00000 6.00000 8.00000 10.00000 12.00000 14.00000 16.00000 16.00000 16.00000 16.00000 16.00000 16.00000 16.00000
4.00000 4.00000 4.00000 4.00000 5.00000 6.00000 8.00000 10.00000 12.00000 14.00000 16.00000 16.00000 16.00000 16.00000 16.00000 16.00000 16.00000
2.80078 2.80078 2.80078 2.80078 3.00000 4.00000 5.00000 6.00000 7.00000 8.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000
4.00000 4.00000 4.00000 4.00000 4.50000 5.50000 6.50000 8.00000 10.00000 12.00000 21.00000 21.00000 21.00000 21.00000 21.00000 21.00000 21.00000
2.80078 2.80078 2.80078 3.00000 4.00000 5.00000 6.00000 7.00000 8.00000 8.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000

All that said now all I have to do is gradually bump them back up until I am content with how it drives. No more high idle and no more driving after I take my foot off the gas