Hi

we've got a little problem with the map sensor we want to use. It should be a 3 Bar map sensor but it seems more like a 3.2 - 3.5 bar map sensor. Its this one here:


seems like a haltech map sensor. I can't find any information about it. it has 749 engraved in it on the top. 749 is actually that what a GM 3bar sensor has. Our Sensor looks very similar to it, but it can't be a GM sensor becouse of the KOEOV and it looks a little bit different!

i measured the Key On Engine Off Volts (KOEOV) and that was 1.47 volts.
at a underpressure in low rpm of -0.65bar the voltage is 0.46 volts.

So for example with crome i make a map with boost tools+ where i tell him that the minimum pressure is about +70mbar and the max pressure is +3233mbar. Then when driving with the car its trying to go to A/F 14,7 all the time, except for VTEC and for full trottle. Even at +0.5bar the car tries to make A/F 14,7 - Lambda 1!

With the original map sensor the proplem is gone and from the first psi of overpressure the car stops doing AF14.7.

So there must be a failure or we are doing something wrong, but what is it?

Thank you, Philip

 

go to gmpartsdirect.com and get you another sensor.

 

are you sure its not a grand national 2 bar MAP, the 3 and 2 bar look axactly the same and have the exact same markings,