MAP sensors reading
 

I measured V reading of two MAP sensors and just wanted to share the results for those interested in comparative data points.

Used a Heise CC calibration gauge (class 4A, 0.1% fs accuracy, fs=200kPa@29psi)

I powered the sensors with 5VDC trough a DC/DC converter (5+/-0.02V accuracy)
Weak link was the digital voltage meter I used - accuracy unknown. The meter reading of the DC/DC output was 5.03 V. I thought it was good enough for quite accurate measurements.

The results confirm what already published by Chuck W. and others. MAP sensors linearity is excellent up to 15 psi, but not beyond that.

The two sensors showed remarkably similar readings and repeatability (I took three measurements at each point and the voltage (to the second decimal) was always the same)

Results are in the attached table.

- Sandro

https://www.rx7club.com/attachment.p...1&d=1258225329

The MAP sensor is linear, to be sure. But how does the fuel injector duration change as a function of the MAP sensor's voltage? That would also be very interesting, since it would include the PCME's response.

Nice graph presentation, BTW.

12V surely?

That depends on your base map.

No, 5V

The MAP sensor is powered at 5V (from the ECU)

Here I added my MAP sensor, currently mounted on the car.

The PIM and PIM voltage readings are the PFC values as read by the Datalogit. There is a little offset in volt readings at different pressures (compared with the two other sensors done before), probably just because the PFC and my meter have different accuracy.

Remarkably, my mounted MAP sensor reading is linear for the entire range, through 17 psi!

https://www.rx7club.com/attachment.p...1&d=1258285616

Since we're sharing map sensor curves, here's my greddy 4 bar compared to the stock. (ignore the teal colored line)

http://i10.photobucket.com/albums/a1...ymapsensor.jpg