Question On Afm

[vhs2]

hey guys, ive got an r33 gtst s2, ive read somewhere that if you unplug your AFM your car should still run? but as i disconnect my AFM my car just dies, what could that be thanks..

[89CAL]

Mine dies without the AFM. always has done with old afm and the z32.

So not sure what happens with other peoples cars. But I don't see how it can run without the engine knowing how much air is going in

[mad082]

the car should run with the afm unplugged, but not very well. it may need some throttle to run, but it should run. from memory it won't rev through the full rev range though, as it will be in limp mode. it may simply stall if you unplug the afm while the car is running, but you should be able to get the car to start/run.

as for how the engine can run without the ecu knowing how much air is going in, it still has the tps value and rpm and o2 sensor which it can use to estimate what is going on. i've unplugged the AFM on a few of my cars before and all have run well enough to drive with it disconnected.

[Cadmoon]

I didn't plug mine back in properly once after cleaning it, ran fine until I hit 2000 rpm then it went straight into limp mode and wouldn't rev any higher. Perhaps Nissan designed it to work under 2000 so you could limp home if it died while driving. On another point, why do you want to unplug your AFM anyway?

[89CAL]

Maybe its just a power fc thing or z32 afm thing or something to do with my car but it won't even start with it unplugged. And I thought the load value was calculated with tps, af-v and the rpm is obviously from the CAS.

But anyway. My car doesn't seem to like it. O2 sensor is only narrowband so cant really provide to much feedback and as far as I know only does anything at cruise.

[mad082]

It would be a pfc thing. They are actually pretty limited compared to a stock ecu. Pfc has 1 fuel map and 1 ignition nap. The stock ecu has about half a dozen maps.