Editing proms (editorial)

[Bruce Plecan]

One change atta time.
One change = one value in one map.
Randomly changing things for the sake of change makes no sense.
If you want to make wholesale changes, how can you tell what changed what
where?.
Grumpy


> I took a look at the Main Timing tables using Tunercat and viewing the
> graph. I see a "hump" in the
> area of 2000-2800rpm and where the MAP kpa is 50-80%. This showed me
> graphically what you were saying and this is the range where the engine
> happens to live at the most. I don't think that the problem rests with the
> WOT region, although AFR for WOT is currently set at 12.5. But I could see
> that by decrementing 1-2 degrees across that particular rpm range, the
curve
> became smoother and lost that hump. Your advice then is to try this small
> change and see what happens. Is the light going on for me??
>
> Dominic
> ----- Original Message -----
> From: "Bruce Plecan" <nacelp at bright.net>
> To: <gmecm at diy-efi.org>
> Sent: Friday, August 11, 2000 3:40 PM
> Subject: Re: Editing proms (editorial)
>
>
> >
> >
> > Beleive me, I write as much as I do to make things as easy as possible.
> > Sometimes my answers aren't popular, but I've done a far amount of chip
> > burning, and talked to hundreds if not a thousand guys off list about
> > tuning.   I also get alot of feedback.  I'll be the first also to admit
> when
> > I'm wrong, thou it might take me making a real fool out of myself in the
> > mean time.
> >    But, ya gotta just get your feet wet, and start, theory will just get
> you
> > so far.   After doing a couple dozen, and seeing what just small changes
> do,
> > you'll get (over) confident, enough to make some minor screw ups, and
then
> > once you relearn things a couple times then you can get somewhere.  Then
> if
> > you can tinker with a few other cars with what you've learned things
will
> > make even more sense.
> >   It's like running the BLM limits real high and low, and letting ecm
> learn
> > it's way in, once you get close to having a nice been, leave the timing
> just
> > right and subtract a little fuel in a couple of spots, and add toooo
much
> in
> > a few others, and go for a test drive.  It will amaze you with how
> different
> > it feels.
> >   That and the stall speed of the converter is enough to make a grown
man
> > cry at times (with a light car, higher then stock stall).   BUT, once
you
> > run thru it a couple times, it's like $hit, ain't nothing, but the first
> > couple serious attempts at a good launching chip for a Hot rod, you'll
go
> > why those dumb ba$tards a GMECM ain't got a clue, and then well maybe,
and
> > then a Owww, that's what they meant.
> >   Grumpy
> >
> >
> >
> > > I start to understand what you mean by using the Diacom only as a
guide
> > such
> > > as the example you wrote about below.
> > > Dominic
> >
> > > From: "Bruce Plecan" <nacelp at bright.net>
> > > > Well er, kinda sorta ya, some cals do have spikes in em, if you
> consider
> > a
> > > > jump of 8 on one block compared to the ones aaround it
> > > > Every once inna while to kill a knock sometimes taking a ton of
timing
> > out
> > > > is better drivialiity wise with a rich spot.
> > > > Grumpy


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