IAC Counts

[Bruce Plecan]

-----Original Message-----
From: Walter Sherwin <wsherwin at idirect.com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Monday, October 12, 1998 12:10 AM
Subject: Re: IAC Counts


>GM changed the fuel pressure spec for the 94-98 L19 TBI engine only, from
>9-13psig to 26-32psig.  I'm pretty sure the other TBI engines did not
>change, although the same concept applies.
>
>Where would I find your "Tune-Up" notes?  I would love to read them.

At the bottom of the DIY_EFI page is a referral to 332 go over there,
and at incoming click on that, and you'll be at the ftp site.  Look
for a couple files about tune-up doc/txt.  My PC is acting up, so I
can't get to my notes here.  If ya have troubles maybe some one
would post the exact address.

Your
>fuel pressure setup is variable .............. Have you altered the
injector
>constant, and the EGR mass tables to match?

I just recently found some related info to that end, and haven't played
with it yet.

  Or did you leave as was?  Just
>curious.

So far as is.
Bruce

>
>Bye.
>
>
>-----Original Message-----
>From: Bruce Plecan <nacelp at bright.net>
>To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
>Date: Sunday, October 11, 1998 4:23 PM
>Subject: Re: IAC Counts
>
>
>>
>>-----Original Message-----
>>From: Walter Sherwin <wsherwin at idirect.com>
>>To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
>>Date: Sunday, October 11, 1998 6:17 PM
>>Subject: Re: IAC Counts
>>
>>
>>>Your comments about the interaction of IAC counts, injector positioning,
>>and
>>>fuel spray pattern with a TBI were great!  I have also twiddled with
these
>>>parameters and have found the same results.  How many IAC counts do you
>aim
>>>for (warm 5-8 ?)?
>>
>>0,Zero. If when the rad fan kicks on, or some other draw 5-8.
>>
>>   I have also found that the Rochester TBI injectors
>>>respond positively to more fuel pressure.
>>
>>Yep,  in the tune-up notes, I mention using two fuel pressure
>>regulators.  One being vacuumed referenced to the engine, and
>>the second one to clip it at a specific psi.  Also, does wonders
>>for deccleration (clean+responsive).
>>
>>  The reward is slightly better
>>>"shattering" of the fuel and a steeper, more regularly defined cone which
>>>helps to reduce part throttle mixture maldistribution (especially with
the
>>>big 454 blades which tend to "paddle" the fuel towards the rear
>cylinders).
>>>Of course, the injector constant has to be changed to match the new flow
>>>resulting from the increased pressure differential.  Starting in 94, GM
>>also
>>>moved in this direction, with a target system pressure of 26-32psig.
>>
>>That is news to me.  Or is this for the CFI system?.
>>
>>Cheers
>>Bruce
>>>
>>>
>
>