Idle screw questions..

[Sharpimage]

Hey folks,

I've been thinking of turning my idle screw out just a little bit so it idles
lower than 750.. I was thinking around 500 or so would sound pretty sweet.
Is the PCM gonna fuss about this at all? also, will i achieve my desired effect
of a deep idle/rumble? Or will the truck just stall out?

Regards,

Andrew

 

[Yellow venom]

Hey Andrew,I have mine idleing at 500,you have to change it in the pcm or SCT tuner,mine idles a little too low,the exhaust rattles a bit,but sounds good at the tailpipe.it will run just fine,I tried to turn mine up a little bit on the idle screw and it hung up really bad,idle came down very,very slowly,So I would say its gotta be done through the pcm,good luck,I will check back to see how you make out.

 

[JeffBoyette]

Interesting question.. during one argument i had on another thread. someone said they disconnected the IAC. I tried it to see how it worked, then I turned down the idle with the screw. It sounded great and stopped 80% of the exhaust backrap and popping. just a deep growl on decel and more engine breaking. I assume the stock tune is programmed to make the IAC allow some air past the butterflys when you first close the throttle to reduce driveline lash or for emissions, time to compensate for rich/lean. Not sure. But i got a CEL.

I plugged it back in, turned the screw equal turns in the opposite direction to put it back to stock and reset the computer. But i still craved the new sound and drivability so i turned the screw back to reduce the idle. The IAC let enough air through to keep the idle where programmed, sounded like shit, idled rough and got some engine knock. and you get a light again. You have to tune the idle to 500 or the iac will compensate.

ANOTHER NOTE: Harley wanna be's aka honda and suzuki's turn the idle down to get that sound and the reduced oil pressure burns the engine up

 

[Sharpimage]

mhmmm, So from what i'm reading if i want to turn down the idle to 500
or so i need to have it done in two places, the PCM and then physically turning
the idle screw out. Does it matter that i have a stage II PCM?
I'm tempted to just "play around" but god knows what that could get me
into.. :shot:

 

[BigRed460]

The "Target Idle" is set in the pcm, if it's not reached the pcm will use the IAC to make it idle where it wants...

The easier way to turn it down is to "twist" the tps sensor...

 

[Sharpimage]

The easier way to turn it down is to "twist" the tps sensor...

haha what do you mean by "twist" I just went out to take a look and
the TPS sensor has two screws in it that prevent it from any twisting.:dontknow: