'165 Minimum Air Question...

[Shannen Durphey]

It really depends on your car.  If you're running a completely stock engine with
factory equipment and reasonable wear, then yes, it's high.  If you're running a
cam with 320/320 duration and 104 degrees overlap, then no, you've actually done a
good job of keeping the IAC counts down.  The number is a guideline that I use when
tuning, when doing tune-ups, and when adjusting minimum air on a mild car with a
working calibration.  

I have never seen an IAC count of 256 displayed on a scan tool.  Even with a faulty
IAC being commanded full open, I've never seen this count displayed.  If it was up
around 100 for a mild engine, I'd be thinking about other ways to get the numbers
lower, and I'd be looking at the throttle plates, intake, etc for carbon and
garbage buildup.  Opening throttle reduces vacuum to things like brakes and pcv, so
it's not a bad idea to get the rpm as high as you can while keeping throttle at a
minimum.  If ya gotta, ya gotta, but
if ya don't...

But it's really a guideline to be used in conjunction with the other factors which
affect idle speeds.

Shannen





Bob Wooten wrote:
> 
> With the car sitting in @ the starting line waiting for the other guy to
> dry hop my car was sitting @ 201 coolant temp, 160 MAT, & a IAC count of
> 93.  would you consider this high?  i checked a number of runs (street
> mostly) & it appears from looking @ the scaling that this is a 256 count
> full scale & I don't think that i ever saw it get higher than 130 or so (a
> peak not average).  this leads me to think that it has a way to go before
> it runs out of room. the amount of flow through the IAC is non linear in
> relation to the count though is it not?  maybe 93 is a ton?
> 
> Thanks
> BW
> 
> > [Original Message]
> > From: Shannen Durphey <Shannen at grolen.com>
> > To: <gmecm at diy-efi.org>
> > Date: 2/13/01 10:14:06 PM
> > Subject: Re: '165 Minimum Air Question...
> >
> > Bob Wooten wrote:
> > >
> > > what would you use as a minimum setting (using counts)?
> > Kinda depends, but I like to see 45-60 or so on the scantool.  T
> >
> > > by poor idle
> > > control you mean that it might surge & pretend that it wants to die
> when it
> > > is just sitting there idling or when coming to a firm stop (firm stop is
> > > kind of like spirited driving only acceleration in the other direction).
> > Anything like spirited not driving?
> > Poor idle control is stalling as soon as it's put into gear, and/or
> stalling at
> > stops, and/or low idle speeds, and/or no A/C compensation, and/or
> sometimes no idle
> > speed flare on startup
> > >
> > > TIA
> > > BW
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