Map sensor showing "half" vacum on idle Microsquirt

[knastenrad]

Hello
Doing an Microsquirt running msextra 3.4.2 install now with GM2 bar map sensor
Map sensor is calibrated from meny in tunerstudio
it shows correct ~ 100 kpa with ignition on .But
The issue is that tunerstudio shows "half" the vacuum 75-80 kpa on idle on the MAP gauge and in the tables etc.
while the PLX gauge and mechanical gauge shows more correct values 35-40kpa
I have measured the volt from the map sensor and it is around 1,6 V which should be 35-40 kpa.

have tried 3 different new map sensors .

any suggestions?

[jsmcortina]

From the calibrations numbers you entered
0V = 8.8kPa
5V = 208kPa
then 1.6V should be 72kPa.

James

[mlynch]

My guess would be incorrect sensor calibration. You can tune the MAP sensor in Tuner Studio.

[knastenrad]

thx for your fast reply

the numbers come from choosing the GM2 bar in tunerstudio

i have not entered any numbers

[knastenrad]

will check for Vacuum leaks then

[nathaninwa]

Is the vacuum source for the plx and ms at the same spot? I'd focus on map hose routing

[rickb794]

The other thing that could affect this is sampling if the vacuum port is on a single runner instead of in a plenum.

If the MAP is sampled at a point in time where the vacuum on a single port is pulsing it could show a different reading.

It's best to take the MAP signal from the plenum. (if you have one)