MAF and 89 Vet stuff

[Romans, Mark]

If someone has an 86 and it's an automatic I would strongly recommend that
they convert to 89 code because it's much better supported and runs better
and eliminates the cold start injector.  If they have a 4+3 they are
screwed.
Mark
----- Original Message -----
From: "TK" <terryk at foothill.net>
To: <gmecm at diy-efi.org>
Sent: Saturday, August 12, 2000 2:44 PM
Subject: Re: MAF and 89 Vet stuff


> hey Mark,
>
> Is the 86 Y body the same as anything else? I don't remember working on
it.
> I think that's the 7703 ECM.
>
> Terry
>
> ----- Original Message -----
> From: Romans, Mark <romans at starstream.net>
> To: <jwn at sgi.net>
> Cc: <gmecm at diy-efi.org>
> Sent: Saturday, August 12, 2000 10:12 AM
> Subject: MAF and 89 Vet stuff
>
>
> > Hi Jason:  I may be able to help you.  I had saved your messages
intending
> > to respond, just a time thing you know.
> > I will try to go through each of your messages and respond to each
> question.
> >
> > Question 1.
> > Questions on MAF equipped 89 Vette.  Using Diacom for some time now and
> have
> > some questions about the different cell numbers used for fuel trims.
What
> > tables dictate the amount of fuel used in open loop mode?  I understand
> that
> > in closed loop the MAF, O2, etc. determine the proper amount of fuel to
> > deliver and adjust the short and long term fuel trims.  What is modified
> to
> > control the fuel delivered in open loop and PE?  I assume its the MAF
> tables
> > but I need educated on what the values represent.
> >
> > Response.  The BL is a group of cells numbered 1-15 in the following
order
> > (As I consult my hand drawn chart)
> > Starting on the bottom left, left to right and each successive row goes
on
> > top of the prev one.  I put the zero's in front of the
> > single digit numbers to preserve the spacing.
> >
> > 12-13-14-15    L             F
> > 08-09-10-11    O            L
> > 04-05-06-07    A  or        O
> > 00-01-02-03   D              W
> >     RPM
> >
> > The rpm boundary numbers stock (These go on the lines between the boxes)
> > 1000,1200,2000.
> > The flow boundary numbers stock, 14 grm/sec, 22,34.
> > These are the block learn memory cells.
> > The fuel settings are "Initial fuel*(BLM/128) = adjusted fuel.  This is
as
> > BL takes fuel out (Lower number) or adds
> > fuel (Higher number)
> >
> > I would not really suggest messing with the maf calibration tables much
if
> > you can avoid it.  I have done some small adjustments
> > in the first table to add about 10% (Below 30 grams/sec) to compensate
for
> > the ported maf in my car.  Other than that I have the
> > injector constant set stock and run about 50 lbs fuel pressure(With
vacuum
> > line off) at idle.  This seems to keep the BL and INT
> > close to 128 at all areas.
> > At all times the maf is used to calculate the correct amount of fuel,
this
> > is closed loop and open loop.  There are tables to add fuel in open loop
> > I have never messed with these.  The only fuel table I mess with is PE
vs
> > RPM.  This allows me to command a richer afr when in pe and the 02
sensor
> is
> > ignored.  Diacom says I am commanding about 12.0 to one at WOT, I know
> it's
> > not really that rich, but then I am maxing out the MAF (255 grms/sec) at
> > about 4700 rpm's.
> >
> >
> >
> > Question 2.
> > I just bought GMEPro and it looks really cool.  I understand the basics
> but
> > need to gain more knowledge.  I had posted a question about block learn
> > cells 0-15 and what in GMEPro controls the amount of fuel the ECM starts
> out
> > with.  I also want to know how to control open loop idle so when I build
> the
> > Superrammed 383 with 30 pound injectors I can make the car idle.
> >
> > Response to question 2.
> > See response to question 1.  Reset the injector constant, I would set
both
> > the single fire and double fire to whatever size injector you are
using).
> >
> > Question 3.
> > For instance:  I have the GMEPro software.  There are 6 MAF tables and a
> > scalar for each table.  What do these affect?  It seems by changing the
> > scalar you can affect the entire table.  The constants are listed as
> counts.
> > Counts?  What is meant by counts?
> >
> > Second, Say when I build my 383 and install 30 lb injectors.  My closed
> open
> > loop idle will be way rich.  How do I reduce BPW at idle with the bigger
> > injectors?
> >
> > Response to question 3.  See response to question 1 & 2.  If you reset
the
> > injector constant to 309 lb/hr injectors.  The ecm will
> > calculate the correct injector pw at idle.
> >
> > BTW what trans are you using?  I have done hundreds of proms getting my
> 355
> > cu in, superram/ 6sp vet dialed in.
> > I may be able to help more.
> >
> >
> >
> >
> > Mark Romans
> >
> > ICQ#66838770
> >
> > Chicks dig scars.
> > Pain is temporary.
> > Glory is Forever.
> >
>
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