On the N18 engine (2013 MCS) if i unplug the MAF shouldn’t the car die?
im still chasing my original issues and cant find anything wrong but so many oddities lead me back to air intake, and i just cant peg it....
Engine is hot, i just got home and lifted the hood while the car was running.
so i unplugged the MAF and told myself ok.. if it dies i know atleast the MAF is functional...
and wait... wait a few more seconds.. idle changes a little, drops...10 seconds go buy the car is running , just the idle dropped a bit and i can see its running a LITTLE rough nothing huge like i would have expected, and i didnt want to floor the engine or anything so plugged it back in and no codes on the dash.... ????? Huh?

shouldnt it have thrown a code the moment i unplugged it?

edit 1 - typical me, i post this then find more info online - unplugging the MAF then starting the car works, as the computer uses a “fake signal” to let it start, but soon will start fouling out.. sounds about right i guess, just dont know if this is true for all maf’s in general or if mini is different.
i didnt unplug it and start the car, i already know that did at one time throw a code because i forgot to plug it in when swapping intakes, and drove it a few miles, got out, and back into the car 45min later and started it up and got a CEL.

so.. no MAF and the car runs? Starts, and stays running? Sounds weird

 

yes...car will still run, although not very well at times....if the MAF is unplugged, the computer will substitute values to keep the car running, but usually in limp mode...

there is a code in there for the MAF sensor....usually takes two times in a row to turn the light on for an engine fault..but every manufacturer is different

Bryan

 

I got the CEL when i accidentally left it unplugged so i know that is functional.
ok, in my typical fashion i did more reading and magically found more info than the last times i searched.

seems as though if a car dies this could be normal as the ECU has to switch to a different type of air metering or use a fake stored signal to run which may not be accurate and by the time it does that the car could die. Otherwise it may stay running then switch to a no so smooth idle or general run rough which is what happened to me.
But this is dependent on the car make/model.

This morning was the first cold day of the year and the first cold day of starting with the stage 3 tune, and its doing exactly what i warned was going to happen by the way it has run since the day the tune was installed.
This morning i start the car and it immediately starts spitting and sputtering and runs like total ****
Idle is surging between 900-1200rpm, up and down.
i rev it up a few times and let it setting down and its fine.
didnt drive it all day til above 530pm when i left work and it didnt spit and sputter but idle was hunting...

I am going to swap over to the CIA again tomorrow before i start it (another 40deg morning) and see if the CIA lets it start clean or if its the same thing.
things keep leading me back to a faulty MAF but i just cant prove it yet, and i really dont want to spend $160 for a MAF to not have it work.
I still need to swap out the intake and exhaust VANOS solenoids too, just haven’t had time to do it

ugh... guess my battle continues, trying to track down my lack luster performance and what seems to be a little too earger of boost with a CIA (which may be narrowed down to the extra throttle response from the tune but i dont like it because its too much boost too soon, and the rpms and engine aren’t ready for it)
And a more control boost pattern with the stock air box in which allows total throttle control and being able to mash on it hard to get full boost, which i prefer, but it just doesnt even remotely feel like 260hp.

 

Unplug it and then try press the gas pedal and see what happens.

MAF is looking at the amount of air flow as a function of throttle. If you are at idle the whole time, the air flow isn't changing. When you press the throttle, you will see the engine struggle and then it likely will throw a light...chances are the engine may stop as well. There are quite a few articles saying the computer simply guesstimates everything and it makes no difference. However, my experience before is that the car struggles at first and seems to act out.