[Gmecm] Re: +AFs-Gmecm+AF0- 2.5L 151 TBI'ed +ACY- Working Great, but...

[Jared Ryan]

TBI doesn't fast-idle nearly as fast as a carburetor.  The maximum 
fast-idle speed in my 9C1 '746 calibration is 1400 rpm.  The fast-idle 
specification for my car with the factory QuadraJet was 2200 rpm.  That's 
a huge difference.

I like not having the engine run so fast at start-up, and not having to 
bump the accelerator pedal to get it to slow down.  The ECM does that all 
by itself, using the IAC motor.

The normal idle speed can vary.  The ECM has tables that let it change the 
idle speed according to temperature and whether or not the air conditioner 
is running.

On Mon, 14 Aug 2006, David Allen wrote:

> In my experience, TBI engines don't fast-idle nearly as fast as a carb engine.  The ECM uses the IAC motor to add extra air to make the fast idle.  The amount of extra air is determined by coolant temperature.  There is a table in the calibration for this function.  If the IAC is frozen the engine will run fine but the idle will be fixed and not able to respond to changes in load or temperature.
> Hppe this helps+ACE-
> David
>
>
>
> +AD4- Ok, got the check engine light figured out... got my oil pressure sender
> +AD4- figured out... only problem now is on startup it doesn't +ACI-fast idle+ACI-...
> +AD4- can anyone explain to me why this would be and what I should check for
> +AD4- (or how even works lol)...
> +AD4-
> +AD4-    +ACo- Idle Air Control maybe?
> +AD4-    +ACo- Is there a sensor that would send info to the IAC that it needed
> +AD4-      to +ACI-fast idle+ACI- in the first place until the engine got +ACI-warmed up+ACI-?
> +AD4-    +ACo- Does it only fast idle in cold weather?
> +AD4-
> +AD4- Those are the only things I can brainstorm about it ATM lol...
> +AD4-
> +AD4- If it is some sort of sensor, how would I test them to see if they're
> +AD4- working properly?
> +AD4- +AF8AXwBfAF8AXwBfAF8AXwBfAF8AXwBfAF8AXwBfAF8AXwBfAF8AXwBfAF8AXwBfAF8AXwBfAF8AXwBfAF8AXwBfAF8AXwBfAF8AXwBfAF8AXwBfAF8AXwBfAF8AXw-
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