IAC Tuner Pro Reading's At Start

Reply Subscribe

Thread Tools

Search this Thread

Jul 18, 2019 | 08:18 AM

rottweiler68

Thread Starter

Member

Joined: Jun 2017

Posts: 143

Likes: 0

From: Illinois

Car: '89 Iroc

Engine: 383 TPI

Transmission: Built 700R4

Axle/Gears: 9 Bolt - 3.45

IAC Tuner Pro Reading's At Start

Having trouble with start and idle on a newly built motor install. Turns over but won't start unless you step on the gas and the it idles very high, without changing rpm's even if you continue to give it gas. So.... logging from TunerProRT, I"m showing the IAC as follow...

IAC Motor Postion - 160
IAC Command Direction - 128

These do not change from just key on, to trying to start, should either of them?

Thank you!

Last edited by rottweiler68; Jul 18, 2019 at 10:50 AM.

Jul 27, 2019 | 11:25 AM

84Elky

Senior Member

Joined: Jun 2010

Posts: 580

Likes: 33

From: Montgomery, AL

Car: 84 El Camino

Engine: 360 TPI

Transmission: 700R4

Axle/Gears: 3.42 + Truetrac, Moser 28 Spline

Re: IAC Tuner Pro Reading's At Start

Quote:

Originally Posted by rottweiler68

Not sure about direction, but IAC should drop immediately when engine begins running to what the code believes the proper IAC position to be (+20 steps if AC is on). A direction value of 128 means no movement is requested. I believe < 128 = IAC is retracting/opening; > 128 = extending/closing. But if no movement, seems like IAC not properly communicating with ECM (wiring connections, etc. )