IAC

[Carnut16]

My truck has been setting off a code for the IAC for about a month now. About two weeks ago, I replaced the entire IAC unit to find that it didn't fix anything. The check engine light still comes on and I'm still showing a code 35 for the IAC. Not only this, but the truck is idling at about 1100-2000 RPM and if I let off the brake, it will idle through first gear and into second. Every now and then it will go down to about 900 RPM at idle. Hell, the truck ran better before I replaced the IAC. Does anyone have any suggestions?

 

[syntax]

Throttle Stop screw for the throttle blades, if its adj to far the IAC cant even compensate for it, do you have datamaster? whats your iac counts at? also whats your fp set at for idle?

 

[Carnut16]

I don't have Datamaster and I don't know what my IAC counts are at. I havn't adjusted anything other than replacing the IAC. Before I replaced it, the truck was idling fine.

 

[Hu Ryde]

might have a huge vac leak

 

[TechWeasel]

might have a huge vac leak

I'm thinking the same thing. The ECU should set an IAC code if it can't control the idle, right? If there's a vac leak, the ECU will "bottom out" the IAC count trying to slow it down, and when it can't, the code gets thrown...

 

[ed hess]

if you didnt measure the pintle length before you screwed the iac valve inyou would damage it so your problem would still be there as this one is now shot!
ed

 

[Carnut16]

Before I screwed the IAC in, I did measure the pintle and it was the correct length (I think 3/4 in.). As for the vacuum leak, I have fairly new silicone vacuum lines I bought from Ian, but one could have been disconnected. I'll check those later today.

 

[ed hess]

i beleive the directions with mine said if you had a high idle afterwards to drive it over 40 mph and it would reset itself.
ed

 

[ed hess]

ya never know but ya did plug the wires back onto the iac. go look now.
ed

 

[Carnut16]

I just checked and the wires ARE plugged in. I also checked my vacuum lines and I can't find a leak. Hmmm.... I might have to take it to a mechanic I know and have him hook it up to the computer to find out what's wrong.