MAF History

[Ken Kelly]

Tom,
	I think you have already talked to Dave Hempstead, He is
doing all our interface work. I am doing the editor. I have
been concentrating on the 94-95 PCM, but quite by accident
have found a number of the 96 E side tables. Someone told me
the 95 and 96 addresses were the same, so I started out to
be able to edit both. It turns out the addresses are
different, however I have a 95 and a 96 E side chip with
almost identicle data in the tables. I have found a number
of the 96 tables just by pattern matching. They must have
added a few items to the 96 tables, because the early tables
are offset by 33 hex, then a little later they are offset by
74 hex. I have put a number of the 96 tables in my editor.
I'd be glad to work with you on the editor, but I suggest
confering with Dave or others for the ALDL interface info.

		Ken

Tom Hussey wrote:
> 
> I have figured about half of the inputs for the '97 with OBDII. If folks
> have figured out the '94/5 inputs most will be the same and would be a
> help to me.
> Andy: if you go that route I can provide some assist.
> 
> -Tom
> 
> andy quaas wrote:
> >
> > Have the important tables/switches been identified in these ECMs?  Can
> > i
> > make a programmer?
> >
> > Andy
> >
> > --- Ward <wspoonemore at excite.com> wrote:
> > >
> > >      GM MAF sensors for 5L engines came out in 1985
> > > for the F car (vette0,
> > > it was Bosch FM type, so called because the air flow
> > > was represented by a
> > > frequency, much like Form MAP sensors. The frequency
> > > as in the 50 Hz
> > > region.
> > >
> > > MY86 F & Y cars used a newer version that was a
> > > variable voltage similar to
> > > the MAP sensor.  Both of these sensors were toped out
> > > at 250 grams/second
> > > electrically, so don't over think how to get more air
> > > trough it, the
> > > computer will never know the difference.
> > >
> > > 250 g/sec is about 280 HP using reasonable BSAC,
> > > (Brake Specific Air
> > > Consumption)
> > >
> > > Buick's used a smaller Bosch built MAF that was an FM
> > > type, I assume with a
> > > lower air flow measuring capability.
> > >
> > > The MAF went away in 1990 due to the very poor
> > > durability record, virtualy
> > > no V8 made through it 100k life w/o a new MAF.
> > >
> > > The came new hot film tech. Much beter reliablilty.
> > > Ater a couple of years
> > > .... The MY 92 - 95 LT1's were equipped with a much
> > > superior Delco modular
> > > MAF that has a higher measurement range.  This back
> > > to a FM type.
> > >
> > > The Current L29 (454) big block truck also uses a MAF
> > > and a MAP, The scan
> > > tool reports air flow in the 300's for WOT, so it has
> > > a higher range.
> > >
> > > The current crop of OBD II GM V8's use both MAP an
> > > MAF, (I think all the
> > > same P/N) to meet the tech requirements of OBD II,
> > > one of which is measuring
> > > and displaying peak power. The MAF is used for this
> > > and primarily for fuel
> > > calculations, The MAP is back up and used for spark
> > > Calculations as well as
> > > several threshold calculations.
> > >
> > > If I wanted to use a MAF I would use the newer PCM
> > > that is used in MY94 - 95
> > > F and Y cars, Its an under hood design, making wiring
> > > a lot simpler, It's a
> > > flash device eliminating EPROM's. Its re programmed
> > > via the ALDL connector
> > > at 8192 baud. Has the ability to handle any kind of
> > > transmission and
> > > excellent diagnostics.  Sort of like using your old
> > > AT to your P2 PC.
> > >
> > > Ward
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
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