reseting IAC ls1

[nathans1987]

how do you reset the IAC in an ls1?? my car idels at 1500rpm when it gets hot??

[chargedvx6]

It is set to always self calibrate to factory presets. Usually IAC probs come from mods or faulty IAC valve or TPS afaik.

Have you done anything with the intake like descreen or porting?

[Peanuts Inc.]

it might be idling high from a split PCV hose.... its a common problem.... look at the t/b straight on and then look to left side of the t/b and there is a black hose that leads over to the rocker cover, it usually splits there and causes a vacuum leak and it idles high

[nathans1987]

it only does it somtimes tho and only when hot usually?? i had a look at all of the vacume hoses n they seem fine

nope no porting or anything its all standard

[Peanuts Inc.]

follow the hose i was talkin about right back around the back of the motor.... and it splits off into 2 lines... it splits there too

is it setting an engine light on the dash when it does idle high???

[nathans1987]

nope never sets an engine light well i did get a tps once but that was only for a second its fine now and its got a brand new IAC coz i kinda killed the old one when i cleaned it hehe.

[nathans1987]

changed the tps that seemed to help quite alot then i found a vacume leak from some sensor at the back of the motor now it idels at between 550 and 900 rpm moslt around 800 not sure if thats mormal i ran if for 20 min usually by then its starting to idel at about 1500+ so by theroy its fine now but i bet when i go on the road itll start doing wierd things again :S

[nathans1987]

hmm still idels at 1000-1100............... its not the iac or the tps or a vacume leak??!!! there is no error codes :S

[chargedvx6]

Have you adjusted the idle screw on the throttle body? The little allen head screw. Try letting it out abit to close the throttle blade more but just remember how many turns you d o so you can put it back to the same spot if this doesn't solve it.

[nathans1987]

it wont be that its too erratic like 1 second its about 350 ideling then i drive a bit and its up at 1100 then i drive a bit more and its at 900 :S

[chargedvx6]

Originally Posted by nathans1987

it wont be that its too erratic like 1 second its about 350 ideling then i drive a bit and its up at 1100 then i drive a bit more and its at 900 :S

If that's the case, it's almost certainly a vacuum hose somewhere like Peanuts was saying. The erratic bit is the IAC trying to constantly compensate for the varying reading IMO.

[nathans1987]

yeah thats what i thought but i cant hear feel a leak anywhere :P i have checked every hose i know off hmm i might just start changing stuff lol coz its obviously really small.