749 861 the logic module uses the manifold absolute pressure map sensor to determine the absolute pressure not the relative to atmospheric pressure of the air inside the intake manifold and the atmosphere barometric pressure.
Gm 3 bar map sensor voltage chart.
This means the output voltage of a 2 bar map sensor with the key.
Linear output based in this info chart shown is for a 2 bar scaling to 29 4 psi.
But all of these sensors must still operate within the same voltage output specs as a 1 bar.
039 460 883 876 2 bar.
3 digit numbers for identification.
Formula for the gm 3 bar map sensor is v 8 94 14 53 i have no idea why it s 14 53 and not 14 696 rounds up to 14 7 but it works out on gm s chart every time.
It is possible that detroit is slightly above sea level and you can use 12 11 in the formula for 1 mile above sea level.
This is the opposite of what should really happen.
Still not 3 bar but a little better.
So in order to accomplish this the output voltage must be scaled accordingly.
Why doesn t it give me the full 3 bar of resolution.
886 012 539 609 701 3 bar.
The map sensor manifold absolute pressure has a 5 volt input and then reduces this voltage according to throttle opening altitude etc and sends the signal to the ecu.
It shows right on the chart top part idle to be to the right side high vacuum low map voltage and left to be wot low vacuum high map voltage.
On my fuel table it only goes up to 26 8 psi.
A 2 bar map sensor will read up to 2 bars of atmospheric pressure difference and a 3 bar will read up to 3.
I have the gm 12592525 map sensor and have it selected as my map sensor.
The op stated the map voltage was high at idle and went down as vacuum decreased.
So by supplying a higher or lower voltage the return signal is varied by the same amount.
Gm map sensor identification how to identify a gm map sensor.
Apparently it s a gm cheverolet performance 3 bar sensor which should have an approx.
Formula for the gm 3 bar map sensor is v 8 94 14 53 i have no idea why it s 14 53 and not 14 696 rounds up to 14 7 but it works out on gm s chart every time.
If i choose the holley it goes to 31 2 psi.
I have looked around to try and find the calibration data for the gm so that i can choose custom 3 bar and get it to work up to 31 2.