Help with high idle????

[jjorgensen52]

I have the front body panels (hood, grille, fenders) off my typhoon, and when i started it the other day w/out the panels, it was idling at 1400+ rpm, even after it warmed up. It also was fighting the brakes when I put it in gear, and jumped to like 10 - 15mph with the brakes off. Does anyone know why it's doing that? I checked for stuck linkages, disconnected vacuum lines, etc, but found nothing. Pictures of disassembled front end @ http://www.typhoon1357.50megs.com/photo.html , in the last 2 or 3 rows of pics. Thanks in advance for any info

 

[Tydriver]

Well dunno how long its been sitting since you have it apart. my guess is the IAC motor is somehow goofed up. Once you exceed 41mph the ECM commands teh IAC motor to full reset (basically recalibrates it to 0) In either event, if you can attain these speeds you may try that and see if it fixes the issue. I havent looked at the link you posted so I dont know what shape the truck is in, but the IAC motor basically is a monitored/controlled bypass around the throttle body to allow the truck to idle/run when parked. It basically allows air past the blades so it will run and not choke itself.

With that said, the only other item I can think would cause an issue is some sort of a vacuum leak or a whacked O2 sensor.

 

[jjorgensen52]

i forgot

i forgot

I forgot to say that the truck ran fine 2 weeks ago and had the battery out until i took off the drivers fender and started it 1st weekend of October.... could that mess up the IAC motor?

 

[Tydriver]

Re: i forgot

Re: i forgot

I forgot to say that the truck ran fine 2 weeks ago and had the battery out until i took off the drivers fender and started it 1st weekend of October.... could that mess up the IAC motor?

YES ! DEFINITELY !! This will do exactly what you describe. The IAC motor needs to be reset in order to function.

 

[jjorgensen52]

ok great... I'll try that this weekend... thanks

 

[fizzler]

how do you reset the IAC motor?

God bless

 

[kwick6]

how do you reset the IAC motor?

God bless

You can check it out by connecting the A&B terminal on your ALDL connector with the ignition
in the OFF position (located under dash drivers side) turn key to the run
position (do NOT start engine) go out to the IAC it will make a slight
growling noise when bottomed out. Now disconnect the IAC and start your
engine set the idle to 650 rpm if it isn't there already. If the Idle has
never been adjusted before you will need to remove the plug covering it. Re
connect the IAC and put the trans in gear the idle should quickly go to the
set RPM.

 

[fizzler]

I just put on my new throttle body (stock from GMC) and it had all sensors already on it. I'm wondering if I need to reset anything (TPS or IAC) or if it comes from the factory ready to go??? It runs ok I guess, still low IAC count though! It hangs around 7 to 8 when the engine is at 180 degrees! I can't find any more vacuum leaks and I'm wondering if I just need to adjust the IAC?

I know this is a stupid question but what is the "ALDL"? Where is it under the dash? And when you say connect the A&B terminal,,, how exactly do I do this? Not a clue here
All of this is still new to me!

Really stumped on this little situation, PLEASE HELP!


God bless