GM MAP Sensors

[Joe Boucher]

Frederic Breitwieser wrote:

> 
> Curious - why are you modifying your MAP sensor output, going to tell the
> ECU you have more boost than you do, as to run a little richer?  Just
> curious!
> Frederic Breitwieser
According to Steve of Swagaero, using a GM fuel injection with a
modified engine requires two general steps: 1) use an op amp circuit to
pull the map circuit signal to where the ecu wants it to be; 2) Change
the tables in the eeprom to a richer mixture to compensate for the
different torque peaks and fuel demands of the modified engine.  

My Camaro idles at about 11 in-hg.  My understanding is the ecm's want
to see 18.  10 in-hg is about 3.00 volts out of the map and 18 is 1.37. 
I haven't figured out this circuit yet.

I wad going to try to design a voltage requlator to output 5 volts so I
could drive my setup in the Camaro for awhile, hooked up to a digital
voltmeter.  I bought a 5.1 zenier diode for about a buck, then I found a
5 volt, 1 amp chip regulator at Rat Shack for 1.65.  Oh well.

The next problem is figuring out how to find the tables in the eeprom
bin files.

Joe Boucher
'70 RS/SS Camaro  '81 TBI Suburban