MAF & base fuel tables

[Ward]

GM origianly used Bosch MAF sensors and were called FM devices by GM
(variable frequency). In MY96 Vettes were converted to a DC (variable
voltage) type. Other GM cars still used FM types, (the big B for example).

The early versions were burdened with an excessive failure rate, and were
phased out in favor of speed-density. (Cost issues). 

The MASS flow approach to EFI is vastly superior to the Speed Density
approach. If you have the air mass and know the injector flow rate, your
done, no calculation requires byond adding fuel at 14.7:1. 

Now GM has gone back to FM types that are much improved in relibility and
range, much for sutable for ECM gifted users. The are much shorter in length
and have a much bigger air flow range, well over the 250 Grams/sec that of
the old type.

Ward
On Sun, 20 Jun 1999 18:19:53 -0400, Knowlden and/or Eller wrote:

> Bruce, thanks again for the acyc.bin from your '87 IROC. I have become
VERY
> fluent in promedit. What I have discovered is that my memcal apyp (89
vette)
> has no base fuel table. Really, I am sure (as sure as a novice can be). I
> would like to know what type of MAF your IROC has. My vette has a Bosch
> analog hot wire (more voltage output more air)but gm has there own, Delco
I
> & II, and they have used a Hitachi. Both the Delco and the Hitachi have a
> frequency output (the higher the frequency, greater the count, the more
> air). The '86 disassembly from ecmguy (what a godsend) would accommodate
a
> frequency based MAF (although the MAf tables appear to be in volts!?). I
am
> thinking this may be the difference. One may lend itself to an equation
vs.
> a table.
> 
> If ya' know what ya' got let me know.
> 
> Thanks.
> 
> Regards,
> 
> Bob
> 





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