Drilling TB after cam
 

what would you start w/ for a A4 w/ hotcam, it idles at about 500 right now and would like it to where it doesnt die when I stop. TIA

also, drill a new one or use factory hole

I drilled mine to 11/64 and it took care of all the surging at a stop. I drilled the factory hole.

what does it idle at now?

Mine idles at the factory 750 rpm. I am thinking of raising it slightly because it will still stall sometimes when the ac is on.

I have an A4 w/the X1 cam and Jayson at MTI told me 5/32'nds or something like that. I'm going to have to check again. And make sure you smooth the edge of the drill...make a lot of difference...I've opened mine up but not that big...wanted to go slowly....

My son is running the LS1 HOT CAM in y2k 5.3 truck
we drill the oe hole, one step at a time going up only 1/64 th at a time were told not to exceed 1/4 in , we did go to 17/64 th all is fine idle at 750

i did 13/64...the car never died..sits at 800

The shop that did my cam install, turned the idle-stop screw, plus some computer tuning. Idles at 750.

Do you have Heads also or just the cam? Maybe Jayson told me 5/32's because I have Stg II Heads also.... :shrug:

You'd be better off to fix the tuning by programming
since there's no easy way to undrill a hole. Changing
the volumetric efficiency params seems to be the
ticket.

JoSeY::I miss stated the size of the hole I intended to state 1/64 over 1/4, NOT 1/64 th over 1/2 sorry, he is running stock heads, is running cam, asp under drive,MW3400-2.2 str,k&n,eaton postract-3.73,Hooker shorties,LS1EDIT,street tires,home made traction bars, at 4900 # runs 14.2 @ 94 mph

Does drilling the TB hold just help raise the idle a little or does it also help smooth out the rough idle somewhat due to the low LSA which caused the P0300 DTC to go set?

Quote:

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Originally Posted by highgear

The shop that did my cam install, turned the idle-stop screw, plus some computer tuning. Idles at 750.

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That is what I did. Turned the screw and raised the idle to 775. :)

Quote:

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Originally Posted by eallanboggs

Does drilling the TB just help to raise the idle speed a litte or does it also help smooth out the rough idle due to the low LSA which causes the P0300 to go set?

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Drilling just allows more air. Because you are running richer.

You cannot raise the idle by drilling or turning the screw. It must be done in the PCM.

:werd:

Does drilling the TB hole just help to raise the idle speed or does it also help smooth out the rough idle a little bit due to the low LSA which ends up causing the P0300 DTC to go set? I have manual trans so idle speed is not as much of an issuse, but random misfires are. I know tuning is the proper way to solve this problem, but can you get some relief using this method?

with my cam (in sig) before drilling the TB it wouldnt stay idling at all, even with my m6. after a few attempts to have the computer relearn the idle with the stock hole settings and no avail, i finally drilled out the TB and it now idles well and stays at a 800 or so rpm.

well, I got it at 1/4 inch, when my foot is on the brake, it sits about 1050 rpms, and off the brake at 1300, it will shift to second while idling. I am going to close up the hole a bit but at least its drivable

Did you drive it a few miles in between each drill size? It can take a several cycles for the computer to adjust to the new air flow. It sounds like you might have gone to far. Does it act like the cruise control is on as you coast to a stop?