afm signal vs map signal?

[amichie]

Note Toyota VAF output decreases with increasing airflow while Nissan MAF increases with increasing airflow.

[Jason Broadhurst]

MAP measures pressure, AFM or MAF measures mass air flow, two very different units. They are not interchangable unfortunatly.

Nissan generally use hotwire, which is 0-5 (0.4-4.7) v.
Toyota are the same but the axis is reversed in some cars I have seen.
Mitsu tend to use karmen vortex which is a frequency/square wave output which increases with airflow.

They are all calibrated highly as well, changing the cal is a bit of a trick to shift load points on a stock ECU but can run in to problems if you arn't careful.

[Duk]

MAP measures pressure, AFM or MAF measures mass air flow, two very different units. They are not interchangable unfortunatly.

Nissan generally use hotwire, which is 0-5 (0.4-4.7) v.

Most Nissan hot wire AFMs continue outputing a higher voltage as airflow increases, but the computers are flat out reading voltage of 5.12v.

[Jason Broadhurst]

They rail and generally cut fuel as 4.7. They can't supply more than 5v (they are only supplied 5v) I didn't think, but I could be wrong I don't have a lot to do with MAF's now days!

[Duk]

They rail and generally cut fuel as 4.7. They can't supply more than 5v (they are only supplied 5v) I didn't think, but I could be wrong I don't have a lot to do with MAF's now days!

This is becoming to Neesahn related but:
Most Nissan hotwire AFMs are supplied battery voltage.
'Fuel Cut' (it isn't a fuel cut BTW) can easily be changed in chippable computers.
They can have their 'fuel cut' raised or totally removed (well actually just made to stupid high numbers).

http://cherrypicker.tripod.com/id10.html

[auto351]

Note Toyota VAF output decreases with increasing airflow while Nissan MAF increases with increasing airflow.

Did you record air flow rates L/S by any chance?
the toyota 1G AFM has a resistor so the output can be reversed, can the Nissan one be reversed ?