I was just wondering, how open should the throttle body blades be at idle. Or should they be all the way closed? Will the IAC provide enough air that the blades should be closed?

Thanks.

 

Check your Factory Service Manual or the Tech Tips section for the proper procedure for the "minimum air" adjustment.

RACE ON!!!

 

siggy, i'm pretty sure you don't have a stock setup but for the LT1 there should be zero air going by the blades at idle. the TB bores even have a coating to help seal between the bores and the blades.

 

Thanks guys. I didn't believe any air should be passing by but I wanted to make sure.

 

LT??? Where did that come from? If the year had been mentioned and I was aware it was a '92 or up, I would have kept silent.

RACE ON!!!

 

Its not an LT . . .its an 86 TPI. I read the proper procedures for this year in the tech tips section about setting the idle.

THanks.

 

yeah, it was hard to give any sort of reply without any info on the vehicle. i did remember siggy had some sort of non-standard setup but that's all i remembered. i took a shot in the dark and guessed (incorrectly) that he had some LT variant.

siggy, if it's not a bother could you let us know what's sittin under your hood?

thanks.

 

Sorry bout that. I tend to forget that C4's also had the LT1's. I love Corvettes and my best friend has an 85 that we work on all the time (in a good way).

I am running the following.

An 86 TPI setup in a 66gmc. Its not the stock motor but rather the TPI put onto my 350. I am running Trickflows 195 23 degree heads. No AC, no EGR or emissions, VATS removed, etc. It has a Th-350 behind it with 4.10 gears. I absolutely love the TPI except at this moment when its acting up.

I reset the Idle Air and TPS and set it at 500 RPM in drive (like the tutorial said) however it was having a hard time staying alive. Still not getting any engine codes. When I plug a vacuum gage, it bounces around as the engine revs and dies. I have checked time and time again for vacuum leaks and there are none. I replaced the coil and module (both were under warranty so I figured if its free, why not). I cleaned the IAC and throttle body too. My friend with the 85 was having a very very similar problem and he ended up replacing the computer which solved it. This problem came on all the sudden which is why I pulled the intake and replaced all the gaskets and what not (it was leaking a bit of coolant as well).

Tomorrow I will try a new IAC and computer (these I can test before buying . . . an advantage of being a past employee of a parts store lol).

Still, its wierd that at times it will idle perfect, but other times, it revs some and dies out some. If I give it some throttle is sings nicely. No popping or backfiring of any sort. I've worked a lot on TPI's but this one is perplexing me.