CasperCasper

I took my intake off today and when plugging the IAC hole for sure can isolate the noise. The car is making an extremely loud screeching all the time through this hole. How did you guys get rid of this? I smoothed out the sharp edges to no fix.

TruckerBomb

iTrader: (2)

I've had this problem with 3 different 102mm throttle bodies. I've changed the IAC motor and it made no difference.

The only thing I've found that makes it go away is going back to the 3 bolt 78mm throttle body. I'd like an answer as well as to what this is.

CamaroRick

iTrader: (24)

Get a Nick williams TB, My china 102 did the same thing. It also had leaking bushings that caused idle issues.

eb110americana

iTrader: (4)

Crap. I've got a 92mm one from China. I hope it doesn't pull that **** when I finally get the car running.

pantera_efi

iTrader: (1)

Hi, I make Vortex Tubes used to cool air, the best work was for Fighter Planes in wing cooling/forced bleed air venting for better turning.

Do research in that area, in the opposite direction.

You will find how NOT to create a Whistle.

Lance

Crf450r420

iTrader: (1)

Not all throttle bodies are machined for the large plastic LS1 pintle, so you are likely using the wrong IAC for it. Unless you have the hard idle set so low it has to be open for the car to run. It is likely just not able to close correctly. GM 17112350 has a smaller metal pintle and is wired the same as the LS1. Now if it only does it while the car is cold then it's just because of the design.

TruckerBomb

iTrader: (2)

Ok, just bought a brand new OEM one... i'll let everyone know next sunday what happens!

Exidous

iTrader: (11)

I've had holley 90mm TBs make a whistling sound on light throttle tip in. My current holley 90mm doesn't do this but when the car first starts up and the IAC is almost full open it sounds like it want to suck in your first born. After 40sec or so it's quiet.

My original 90mm was straight through. The current one has a machined hump to help low speed drivability similar to the quality 102s you find out there.

TruckerBomb

iTrader: (2)

Made zero difference. Still whistles.

Crf450r420

iTrader: (1)

Is it just when cold or even after motor is warm? Cold can be normal if it goes away warm. If it does it warm then the hard idle could be so low the IAC is open all the time. You have the wrong IAC or there is an issue with the wiring and it isn't closing. Start with some tape over the port and confirm that is the source. Next if that is the source, I would pull the IAC out and manually pull the pintle out so when you bolt it back in the port is closed. If this fixes it and the car won't run cold, then the computer isn't controlling it. You could also start and run the motor, rev it up to 2500 rpm for 10 seconds and disconnect the IAC plug while still at 2500. Shut the car off and pull the IAC out. If it's still isn't closed then the computer isn't controlling it for some reason.

TruckerBomb

iTrader: (2)

Bit of an update. Using said AIC motor, and after a retune, that whistle is GONE.

soooo, check your tune and buy that part number.