[Gmecm] 1227747 rpm vs gear table
Darryl M Gilbert
dgilbert78
Wed Jun 8 20:27:41 UTC 2005
David: Good for you on your tune success. I have also found another thing
that i totally overlooked, and that was speedo gearing. When i did my
swap i now understand more than i did from the start that before starting
any tuning one should make absolutely sure that all is in perfect working
order. MAP, IAC, O2 sensor, Knock, Ign Module , Dist phasing, and even
correct speedo gearing. Seems if one of those is incorrect it just makes
life a real bear trying to tune around a malfunction you are not aware
of. About tuner cat you are correct. On IAC alone there are a ton of
things here and there in the tables that are not covered. I found these
by just constantly searching the web, and have found some good stuff that
i do not know what i am going to do with yet Ha! I agree, i really do not
want a shift light, and do not care if i ever see one. I just found it an
interesting visual thing that would give me some feed back on what i was
changing in the EPROM. I have found nothing so far on that portion of the
tables. I have also finally figured out how by looking at those tables if
the PROM is for an auto or manual trans. That info i have not found
either, but think i have discovered how to determine that. I am not
really looking forward to the 100, 200, 300 chip burning, thats why i was
thinking about the romulator, I have heard good things about that route.
I figure i could always resell it and recover some of the expense. Thanks
for the reply
Darryl
On Wed, 8 Jun 2005 08:01:27 -0500 "David Haggard" <david at newcovenant.com>
writes:
> Darryl--
>
> Thanks for the insight. But like I said, I find the light just plain
> irritating, and basically useless because of where it is located on
> my dash (far right, and out of line of sight when driving).
>
> >From what you just described, I now understand what that table is
> for that I never used. (The mph/rpm ratio table.) When I started,
> the TunerCAT definition file for '747 didn't have that table defined
> yet. I never saw it until I downloaded an update after I had already
> disabled the light. That table wasn't right for my car, because the
> '747 bin I started with was one from Edelbrock for a different
> model. My car originally had the 1228063 ECM, and the TunerCAT
> definition file for it was definitely lacking in the settings I
> needed. My 305 build is so radical (1.25 horses per cubic inch
> without power adders) that I had to use a combination of TunerCAT
> and WinBin to get it right. Even had to build my own WinBin
> definition file to get all the settings I needed. And even with
> that, the only way I found to get a stable idle was to force it to
> open loop idle by setting the open-loop idle threshholds at
> 1175/1200 rpm, and opening up the throttle plate to allow less than
> ten IAC counts at idle. That gives me a lopey but stable idle at 700
> rpm, where a closed-loop idle will hold for a few seconds, then try
> to stall, then jump up, then settle in again. Even if I shot for a
> high idle speed.
>
> But I digress....
>
> I haven't used RT Tuner. I've built my car on extremely limited
> budget. Get the parts as I can save up for them and buy them
> basically one at a time. Took me 9 months to build the motor that
> way! So while RT Tuner is a great piece of software, I haven't been
> willing to spend another nearly two hundred bucks to get the
> software and the ROMulator. So I did it the "old fashioned" way like
> Bruce Plecan described. Like him, I've burned about 100 chips to
> "get it right," and another 300 to "get it perfect."
>
> Glutton for punishment-- Now I'm looking at building an LS2 copycat
> starting from a 350, to get the torque that the 305 lacks.
>
> David
>
>
> > -----Original Message-----
> > From: gmecm-bounces at diy-efi.org
> > [mailto:gmecm-bounces at diy-efi.org] On Behalf Of Darryl M Gilbert
> > Sent: Wednesday, June 08, 2005 6:51 AM
> > To: gmecm at diy-efi.org
> > Subject: Re: [Gmecm] 1227747 rpm vs gear table
> >
> > David: From what i have learned so far you are correct
> > partially. The TCC tables, and shift point tables, and load
> > tables are all inter connected.
> > The TCC portion of the tables control shift light if no TCC
> > or Kick down relay used. you simply do not connect any of
> > these things. At this point you can use a light to show best
> > shift point. Yes the ECM does not use this data for anything
> > when shift light is used, but does use this stuff when TCC or
> > Kick down relay. is required. I was just playing with it to
> > better understand how the tables were derived. I do know that
> > the 1st table does tell the ECM what gear you are in based on
> > MPH/RPM ratio If these ratios are correct for your car it
> > will then point to the correct entry in the shift point
> > table. So far I have it working properly in 1st and 2nd but
> > when in 3rd it still thinks i am in 2nd, this means the 1st
> > table in my case is still incorrect. For 4th gear it is
> > correct for i have that set to 254 and the light no longer
> > comes on. What i was wanting to know is how is the first
> > table computed?. I just wanted to know this to understand how
> > they arrived at the numbers in there To determine what gear i
> > was in i set the shift light at several points 1st 3000, 2nd
> > 2500, 3rd 2000 and 4th 254 which is probably 200mph or better
> > when in 3rd it still comes on at 2500 RPM meaning it did not
> > move to the proper point in the shift table. It does however
> > know i am in 4th for light never comes on like i told it not to.
> > thanks for the reply...did you ever use RT TUNER??????
> > Darryl
> > On Wed, 8 Jun 2005 01:32:30 -0500 "David Haggard"
> > <david at newcovenant.com>
> > writes:
> > > I have an '88 Firebird with T5 manual, and running a '747.
> > The shift
> > > light does not let the ECM know what gear you are in. Just the
> > > opposite. It uses vehicle speed and engine load to turn on
> > the shift
> > > light so you know when to shift for best fuel economy vs.
> > how hard you
> > > are accelerating.
> > >
> > > My Firebird, even though the shift light is a stock feature, has
>
> > > nothing to indicate to the ECM what gear the transmission is in,
>
> > > except 5th gear. There is a switch in the side of the
> > transmission to
> > > do this. It is only switched on when in 5th gear.
> > >
> > > I'm afraid that with your Saginaw 4-speed, you won't have
> > any way to
> > > control the shift light in 4th gear. So when you get in top
> > gear and
> > > settle into a cruise mode, the shift light will switch on
> > and stay on,
> > > unless you give it more gas for power enrichment mode.
> > >
> > > Somebody correct me if I'm wrong about this.
> > >
> > > Personally, I always found the shift light to be an irritation
> at
> > > best. Mostly it's useless because it's neither bright
> > enough nor in a
> > > good position to be effective. So I have disabled it.
> > >
> > > If you don't have a shift light installed, then don't worry
> > about it.
> > > It will have no affect on your tuning. But if you do have
> > have a shift
> > > light, or you want to be sure it can have no affect, then
> > here are the
> > > settings I used. The shift light circuit also controls the
> > TCC with an
> > > automatic transmission. I set it up to turn on the shift
> > light ONLY if
> > > I over-rev the engine. My self-declared red-line is 5500 rpm,
> even
> > > though the motor will easily rev well past 6000.
> > > Don't want to blow it up! But I doubt I'll ever notice the light
> if
> > > I'm revving that high!
> > >
> > > With these settings, my shift light will not come on unless
> > I rev past
> > > 5500 rpm or get over 255 mph.
> > >
> > > In the ECM Constants table (TunerCATS software):
> > > TCC Lock, Low Gears, High Speed: 255 mph
> > > TCC Lock, Low Gears, Low Speed: 254 mph
> > > TCC Lock, High Gears, High Speed: 255 mph
> > > TCC Lock, High Gears, Low Speed: 254 mph
> > > Force Shift Light On RPM Threshold: 5500 rpm
> > >
> > >
> > > Dave Haggard
> > >
> > >
> > > > -----Original Message-----
> > > > From: gmecm-bounces at diy-efi.org
> > > > [mailto:gmecm-bounces at diy-efi.org] On Behalf Of Darryl M
> Gilbert
> > > > Sent: Saturday, June 04, 2005 9:04 PM
> > > > To: gmecm at diy-efi.org
> > > > Subject: [Gmecm] 1227747 rpm vs gear table
> > > >
> > > > Hello: Really new at this, so bear with me. Getting feet wet
> on a
> > > > 1227747 running a 355 TBI. Have several issues, but lets
> > take them
> > > > one at a time (easy ones first) There is a table associated
> with
> > > > SHIFT LIGHT. It appears to be able to let the ECM know
> > what gear you
> > > > are currently in. I would like to know what is the formula for
>
> > > > calculating the entries into this table. Using a 4 speed
> > Saginaw, so
> > > > i guess 4th is not used due to no more gears left to
> > shift to. Does
> > > > that make any sense?
> > > > thank you
> > > > Darryl...
> > > > _______________________________________________
> > > > Gmecm mailing list
> > > > Gmecm at diy-efi.org
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> > > >
> > > >
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