TUFF LT1

Well my car wouldn't idle for anything after the cam install. Last night I removed my throttle body air foil and it fixed the idling problem a bit. the car still wants to idle very low. My IAC counts wouldn't drop below 100 or so with the TB air foil in but once it was out the counts went down to about 80. I'm pretty sure that I need to drill the hole out in the TB to let more air in but exactly how big do I need to drill it with my IAC counts at 80 now to get them to the 20-40 range. I've read that some have drilled to 7/32 and 1/64. What do you think?? Thanks for any input

TUFF LT1

that was 11/64. sorry

CoUnTryMuZiCZ28

I drilled mine out with a 5mm bit and moved it around to make it a tiny bit bigger.. My IAC counts are 30-50.. you dont want them to low either.. Its different depending on cam and stuff.. I would just drill it out a tiny bit and then put it back on and see what it does... Worth the work instead of guessing and then ruining your TB..

TUFF LT1

Good idea, thanks for the info!

grumpygreaseape

how big of a cam? before you drill anything, why arent you working with the minimum air setting? slot the tps screw holes to allow adjustment back into spec. as you open up the blades? the pcm is only going to let it idle where it wants to see it. a big cam is going to want a higher idle speed-that means some limited re-programming is the answer.

CoUnTryMuZiCZ28

No. The Blade adjust screw is temporary.. You will cause hesitation problems if you have them cracked open. they must be 100% closed. The IAC will be working at a higher count then it normally would with a bigger cam.. which would cause idle problems. the counts would see 70-120 with a bigger cam, you need to bring them back down to 30-50. you need to drill out the bypass hole a bit to let more air in.. There are special passages in the intake manifold for the Idle Air.. Yes with a stock cam your car would run fine.. GM didnt plan ahead and do the tweaks for what youd be doing in 5 years.. If cracking the TB blades was the answere then why didnt they just put bigger blades and not special passages and just keep the blades a tiny bit open at all times? hehe.. The Blade stop screw is more for diagnosis, thats to see if you need more air at idle or not.. or to test if your IAC is bad i suppose..