NefMoto

so im wanting to convert an me7.1.1 car to a hitachi maf.
my notes:

(http://i795.photobucket.com/albums/yy231/k0mpresd/maf_pins.png)

w8 bosch ecu/maf pin:
26 / 1 / yellow / iat sensor wire
d22 / 2 / green/yellow / +12v
27 / 3 / green / connects to brake boost pressure / ground
53 / 4 / lilac/yellow / +5v
29 / 5 / black / signal

s4 hitachi ecu/maf pin:
53 / 1 / lilac/gray / +5v
? / 2 / green/yellow / +12v
27 / 3 / black/green / ground
29 / 4 / green / signal

s4 bosch ecu/maf pin:
g235 / 2 / green/yellow / +12v
27 / 3 / black/green / ground
53 / 4 / lilac/gray / +5v
29 / 5 / green <- black connects @ 200 (ground connection shielding) / signal

so since the ecu pin #'s seem to match up pretty well, this is what i figured:

hitach maf pin / color      w8 color / purpose:
1 / lilac/gray        lilac/yellow / +5v
2 / green/yellow             green/yellow / +12v
3 / black/green        green / ground
4 / green                black / signal

my only really concerns were a) do my notes look correct? and b) why is there a 5th (yellow) wire on the original 7.1.1 maf?
EDITED TO ADD IAT WIRE NOTE.

It looks like the extra wire is

27 / 3 / green / connects to brake boost pressure / ground

Is the MAF supplying ground to that wire, or is it receiving ground?

If all the signal wires match up, looks like it'll work fine. What maf tables are you going to use? Was the hitachi maf ever an option on that particular model?

how does that look like the extra wire? did you read all 3 pinouts? there are 3 ecu pins common to all maf's. 27, 29, 53, and a 12v power wire connected not from ecu.
i patched hitachi maps from an s4 file as a starting point.

so i had an epiphany today and figured that the extra wire in the original harness is for the iat located in the maf.
turbo cars have external iat in the manifold, n/a cars have the diode built in to the maf.
and on top of that, i was looking at the hitachi maf today and it appears it has an iat diode built in as well. wonder if its wired internally? one way to find out. :)

well, just in case anyone ever references this, the wiring is 100% correct. also, adding a 5th pin to the stock hitachi maf connector and connecting it to the yellow (extra) wire in the harness gives a working iat sensor.

Whoa. Interesting find.

I can't imagine the signal->temp scaling is the same though... is it?

you know to be honest i didnt even really think about that.
thats a good point. ill pay more attention the next time im at the car. really i was just more excited that it was all working. :)

there really is only a few types of thermistors they use, precon type-x is what i have found in like almost every application ever.  but who knows in automotive. just something to look into maybe.