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3 Bar MAP Sensor info

5K views 6 replies 5 participants last post by  Gav72 
#1 ·
At some point I intend to fit a 3 bar MAP sensor to my 9k to enable mapping above 1.54 bar .

Anyway in preparation for this I have today taken some readings and plotted some graphs:



Not a problem per se, 'cos I won't be want more than about 1.8bar. But it does seem like I've been sent the wrong sensor.


Now, all I have to do is work out how to get this mapped into my ECU...
 
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#6 ·
I expect it will throw the air/fuel ratio out completely. From the above graphs, the ECU will have to know you have a 3.0 bar MAP sensor fitted to the car, otherwise it will not interpret the signal correctly. For example, when the pressure is 0.5 bar, the 3 bar sensor will output 2.25V. The ECU, calibrated for a 2.5 bar sensor, will interpret that voltage as 0.3 bar manifold pressure, because that is the manifold pressure that will cause a 2.5 bar MAP sensor to output 2.25V.

Remember that a Trionic 9000 has no air-mass meter so the air-mass is calculated from other parameters, of which the manifold absolute pressure is a very important part.
 
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