[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: MAF and 89 Vet stuff
I upgraded my 84 ECM to a 7747 from Turbo City. My 4+3 OD works well enough
although not exactly as original. In the original program from TB City, it
would not engage when flipping the switch. Later, Turbo City provided
iterations of the chip which enabled OD operation thru switch and
accelerator. My only real problem at this point is that the trans will drop
out of OD at hi speed when TPS is near or at closing. Can't tell at this
point but I would estimate about 20% TPS. However, kickdown to direct will
happen at about 74mph. Therefore it will coastdown in OD say from 85mph with
<20% TPS until it reaches 74 mph at which point direct gear is engaged.
Tapping accelerator brings back OD. At low speed, OD disengages at 34mph
with <20% TPS. OD operation was enabled with NO pin reconfiguration at ECM.
Is there any way to remedy (eliminate) kickdown at hi speed either with
software change or pin reconfig?
Dominic
----- Original Message -----
From: "Shannen Durphey" <shannen@grolen.com>
To: <gmecm@diy-efi.org>
Sent: Sunday, August 13, 2000 6:52 AM
Subject: 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.
> > > > >
> > > >
> > >
> >
> --------------------------------------------------------------------------
> > > > --
> > > > > To unsubscribe from gmecm, send "unsubscribe gmecm" (without the
> > quotes)
> > > > > in the body of a message (not the subject) to
> > > majordomo@lists.diy-efi.org
> > > > >
> > > > >
> > > >
> > >
> >
> --------------------------------------------------------------------------
> > > --
> > > > To unsubscribe from gmecm, send "unsubscribe gmecm" (without the
quotes)
> > > > in the body of a message (not the subject) to
> > majordomo@lists.diy-efi.org
> > > >
> > > >
> > >
> >
> --------------------------------------------------------------------------
> > --
> > > To unsubscribe from gmecm, send "unsubscribe gmecm" (without the
quotes)
> > > in the body of a message (not the subject) to
majordomo@lists.diy-efi.org
>
> --------------------------------------------------------------------------
--
> > To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
> > in the body of a message (not the subject) to
majordomo@lists.diy-efi.org
> >
>
> --------------------------------------------------------------------------
--
> > To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
> > in the body of a message (not the subject) to
majordomo@lists.diy-efi.org
> --------------------------------------------------------------------------
--
> To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
> in the body of a message (not the subject) to majordomo@lists.diy-efi.org
>
----------------------------------------------------------------------------
To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
in the body of a message (not the subject) to majordomo@lists.diy-efi.org