toyota 20v 4age afm with microsquirt code

[ChaosAD]

I wish to use the standard toyota 4age 20v AFM with my v3.0 ms2 ecu.
It looks like the only option is to load the microsquirt code.

The afm is a flap type and provides a 0-5v output, but full load is close to 0 volts and no load is close to 5 volts.

Will this work with the microsquirt code? or will the signal need to be inverted?

Rewiring the afm is not an option.

Thanks,
Scott

[grippo]

This should work. You put in a table of voltage vs maf flow and it doesn't care how the flow curve looks.

[ChaosAD]

Awsome.

What is the best way of getting a voltage vs maf flow table to start with?

I have an old datalog with rpm, map, afm volts, mat etc from when it was running SD but logging afm volts.
Is there an equation I can use to work it out? or will it be close enough to use as a starting point if I just guess the values?

Thanks

[grippo]

You can get an estimate of airflow from the map reading using the following eq:

airflow(g/sec) = (((map * rpm * CID) / (mat + 459.7)) / 1167.47) * VE

where mat is manifold air temp in deg F, map in kPa and CID is the engine cubic feet displacement.

If you had a known, calibrated MAF sensor as well as a map sensor you would be able to use this eq to calculate a pretty decent VE table.