In Spec.?

[PlayingWithTBI]

If IAC valve had issues wouldn’t it throw a code?

IDK for sure but, FWIU the PCM sends commands for how many steps the IAC should open/close but, there's no position feedback.

Can you see IAC steps commanded? Maybe put it in gear and see what your PCM commands. If it's still trying to close, you may have a vacuum leak.

 

[Caman96]

IDK for sure but, FWIU the PCM sends commands for how many steps the IAC should open/close but, there's now position feedback.

Can you see IAC steps commanded? Maybe put it in gear and see what your PCM commands. If it's still trying to close, you may have a vacuum leak.

Not sure how to see that using Dash Command. No codes present.

 

[Caman96]

Just figured out how to test that, thanks. This video explains. Will report back.

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[Caman96]

Ok, I just confirmed the PCM is sending commands to IAC. According to this ^^^ video it’s likely the IAC(# @xXxPARAGONxXx).

 

[Schurkey]

At temp and in gear I’m still at 650 rpm when it should be 550 rpm’s.

Tach accurate?

Will your scan tool show actual RPM vs. commanded RPM?

 

[Caman96]

Being that it fluctuates slightly (SAE.RPM), wouldn’t that be actual?

Tach accurate?

Will your scan tool show actual RPM vs. commanded RPM?

FWIW, the Dash Command RPM is matching the RPM tach on truck.

 

[xXxPARAGONxXx]

Depends how bad it is.

All that being said, your RPM won't be on the dot. Air temp, coolant temp, engine load all play a part in VCM calculating idle speed. It's going to vary.

 

[Caman96]

Depends how bad it is.

All that being said, your RPM won't be on the dot. Air temp, coolant temp, engine load all play a part in VCM calculating idle speed. It's going to vary.

How bad what is?
At temperature, in gear at idle I should be 550 rpm, but I’m at 655 rpm. It’s consistently like that. I’m just thinking 105 rpm’s higher seems to high.

 

[Caman96]

Here’s another thing - can anyone confirm rpm’s at idle in gear?

 

[xXxPARAGONxXx]

How bad what is?

How dirty (bad) the IAC is.