MAF Voltage high with no airflow

[hdcdenham]

Hi,

I hope someone can shed some light on my current issue. I have been preparing to move to MAF for fueling and configured my MS2 V3.0 as detailed in the MS2 extra manual.

I am using JS5/AD6 and have added the ceramic capacitor and 1K resistor as shown and have routed it to SPR4.
The MAF is a Bosch 0280218010 so has IAT on pin1, 12v Pin 2, Sensor Ground Pin3, 5v Ref Pin 4 and MAF Output voltage on Pin 5.

I enabled MAF on AD6 but kept the fuelling on MAP so that I could have a look at MAF Voltage and Airflow on TS Gauges whilst the car was running. I expected an IDLE MAF of just over 1v but am getting about 2.3 volts. The voltage does increase very slightly when I rev the engine.

I have a second MAF sensor so plugged that in outside the airflow and started the engine again. Again MAF voltage over 2 volts with no flow but obviously no response when revving.

I started the engine with no MAF connected and I get a voltage of 4.95 i.e. 5v Ref, I presume because AD6 is floating as it is not connected.

I have checked and rechecked my board MODs and external wiring but cannot see anything wrong. The only difference from the instructions in the manual is my Ceramic Cap is 50v rather than 10v.

Please can anyone shed any light on the problem.

Thanks
Hamish

[hdcdenham]

Quick update. Disconnected the signal wire from the MAF and measured actual voltage being produced with no air flow = 0.97 volts, blow through the sensor and voltage increases.

So why is Megasquirt reporting a higher voltage?

Help Please.

[Blown88GT]

...I hope someone can shed some light on my current issue...The MAF is a Bosch 0280218010...

Did you enter the MAF calibration curve into Tuner Studio?

[hdcdenham]

Hi yes loaded the MAF curve. Found the problem - I had a high resistance wire from the MAF to the Megasquirt. Rewired and now getting much more sensible results.
Thanks