What does the IAC actually do

[devilly]

just wondering what the iac actually does,is it like the air/mixture screw on a carby ?

 

[delcowizzid]

its idle control opens when the engines cold so it idles and opens and closes when fans and a/c turn on and off and when you shift into gear to stop stalling.

 

[IBLOWN]

Like delco said, its a stepper motor that by-passes air around the butterfly in the throttle body to keep the revs steady at idle.

 

[devilly]

oh kewl thanks heaps that explains it so this could be the reason it shakes on idles,took it out and had a look yesterday the thread is heaps worn on it.getting a replacement could this also be the reason my petrol is coming straight out my exhaust?drove for 5mins used 1/2 a tank of fuel....

 

[vyseriesII]

Id' be looking at your o2 sensors to if you have raw fuel coming out the back pipe. It sounds to me they are not working at all and would also make car ruff as guts

 

[devilly]

oh kewl thanks for that, will look into it couple of months ago had extractors put on and seems to be getting worse every drive since then....

 

[devilly]

Thanks heaps vyseriesII's have been researching alot about the o2 sensor will be getting them asap i found this
A lot of factors can affect the relative richness or leanness of the fuel mixture, including air temperature, engine coolant temperature, barometric pressure, throttle position, air flow and engine load. There are other sensors to monitor these factors, too, but the O2 sensor is the master monitor for what's happening with the fuel mixture. Consequently, any problems with the O2 sensor can throw the whole system out of whack

 

[gm1961]

5 mins = 1/2 a tank, , thats sound more like a big hole in the fuel tank or line

Think of the iac sort of a fast idle like a cold choke ( but it does not richen the mixture ) and a bit or a little tiny rev holder for when the aircon is on

 

[Husky]

New extractors usually kill off o2 sensors just after install due to the coating on them from new. That would explain high fuel usage, but I'm sure half a tank in 5 minutes is an exaggeration.

 

[Nut Kracker]

What does the IAC actually do

just wondering what the iac actually does,is it like the air/mixture screw on a carby ?