AFM signal wire specs

[Mike]

I have been kinda concerned with my 2.8 m20 with a 272cam, and MAF conversion. It cuts out/throws 1215 code, whenever I take it over 5k, depending on how much throttle I feed it. Full throttle is ok, but 70-90% throttle makes it upset, and cuts the revs hard. I took voltage from the air flow signal pin, at the dme harness, and it peaks at 5.1 - 5.2 volts.

I hear that stock afm peaks around 4.8, is that right? What about idle?

[nando]

5.1-5.2v is close enough to 4.8 (it's nominally 5v). I'm not sure off the top of my head if it's 0-5v or 1-5v, but idle would likely be around .5-1v. What MAF conversion is it?

what code is 1215?

[Mike]

1215 - Indicates problem relating to Air / Mass Flow Meter - AFM or MAF depending on your e30 model. Causes could be cable wire damage, short circuit in the unit, or air / vacuum leak (check air intake hose - big L-shaped one)

This is all Miller stuff, Gen I MAF, w/ war chip. I ran split second's kit on my old e30, and it would cut revs the same, but usually a minor adjustment with their arc2 calibrator was all that was needed. All that thing did was fake/condition the signal coming from the MAF/AFM. I've been back and forth trying to get it sorted out, but I'm kinda trying to button down WHAT actually needs to be sorted out.

[nando]

are you able to measure the voltage output of the MAF at the moment that it cuts out?

[Mike]

Tough to say, because it depends on how hard im on the throttle. soft acceleration, the cel comes on roughly at 5 volts. it will cut out only between 70-90% throttle. full throttle will go all the way to 7k.