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Re: MAF and 89 Vet stuff



88 4+3 is still better than 86.  Requires moving one pin at ecm.
Shannen

Romans, Mark wrote:
> 
> 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@foothill.net>
> To: <gmecm@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@starstream.net>
> > To: <jwn@sgi.net>
> > Cc: <gmecm@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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> > >
> >
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> >
> 
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