Airflow meter swap

[jakobsladderz]

Karman vortex airflow meters are essentially linear devices. This means that for a doubling of airflow, you get a doubling of output frequency. this makes it easy to adapt other karman vortex type sensors into the car. You cannot use a resistor or afc to trim the fuel because these all change voltages, not frequencies, but you can adjust the bypass holes in the AFM to suit.

Vortex airflow meters work best over a certain range of airspeeds. the reason for the metered tunnel and the unmetered holes is to give the right range of airspeeds to suit the engine, whilst ensuring optimal airflow through the sensing tunnel.

Put whatever mitsubishi AFM (vortex type) that will fit your airfilter. put the existing starion air temp sensor into the new AFM(your ECU is callibrated for that). Wire correctly.. Try starting the car. If it runs, but is too rich, open up more vent holes (less air through metering tunnel). if it is lean, close down some metering holes. Bob's your uncle (perhaps, just a guess..)
The reason for both the MAP sensor and the Airflow meter could be a number of reasons. airflow meters generally don't work well whilst cranking, MAP sensors are fine. Whilst airflow meters measure the volume of air, good for deciding how much fuel to put in, they aren't good for measuring the boost level for things like overboost cutoff. finally, it also means that one sensor can break and the car can still get home, albeit running a bit rough perhaps.

[jakobsladderz]

This post was meant to go into the airflow meter discussion a few topics back, anyway, I stuffed up...