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Re: MAF and 89 Vet stuff
89 Calibration is different, as it's for a 6 speed. There's no
control for the o/d unit.
The 88 schematics are on the ftp site. IIRC, Pin C8 is O/D switch in
86. In 87 they moved the O/D sw to pin c7 and put a a first gear sw.
in the trans which connects to pin c8. Leave c8 open and the o/d
operation will be the same as you're used to. You might be able to
use the an auto cal., use tcc tables for o/d, and use a different
switch for o/d control. It would be an interesting project.
Shannen
J. T. Spilman wrote:
>
> I just upgraded my 4+3 85 to an 89 ECM I jumped two wires to get the O/D
> switch to work. What pins did you move to get the O/D to respond correctly?
>
> Thanks
> JT Spilman
>
> -----Original Message-----
> From: owner-gmecm@diy-efi.org [mailto:owner-gmecm@diy-efi.org]On Behalf
> Of Shannen Durphey
> Sent: Saturday, August 12, 2000 11:25 PM
> To: gmecm@diy-efi.org
> Subject: 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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