Quick question related to the MAF!
 

Hello everyone, I always wanted to change my MAF but I never got around to do so, I read around about how people remove the MAF just to test it out without the MAF to see if there is any difference and they do indeed feel a difference, now before I change my MAF i also want to remove it and test it without the MAF connected, only question I have is, is it safe to drive without the MAF? will my SES turn on? anything bad will happen?

01 X5, 4.4i - 124k.

number of times MAF was used = 6
:D

So you drive with a disconnected MAF? Is that safe? and if it is does it bring up the SES light?

It is ok to drive with it unplugged as it won't damage anything, and it should run ok. The SES light will come on. What happens is the DME doesn't see a signal/reading from the MAF and has to substitute its own default values just judging by the RPM, load on the engine and O2 readings etc.

Thank you very much Weasel :)

Before I go ahead and mess anything up, is there any simply D.I.Y. on how to disconnect the MAF? I never did disconnect it before and I just am a little precautious about it.

There's a plug on it. You just unplug it and go. Buy some MAF cleaner as well, and see if that'll save you from buying a new one. MAKE SURE IT IS MAF CLEANER. Carb cleaner will damage it.

And you should be able to use any ODB2 code reader to clear the SES light afterwards.

Well,if it runs ok without MAF connected,so please explain to the dumb what precisely MAF affects?
I just disconnected it and no SES light so far,what I can say,I can say that shifts are softer...should my MAF be already bad?

Hard to know if it is bad or not when it isn't far out enough to cause mixture faults. But what the MAF does is measure the amount of air being sucked in the engine and the temperature of it etc. so the DME knows how much and how dense or air is in the combustion mix thus how much fuel to spray. Then it uses the readings from the O2 sensors to see how the combustion did and if it needs to add or subtract fuel from the next combustion cycle.

I remember when I unplugged my MAF one time to troubleshoot a poor running condition I had. It would trip the Trans Failsafe program when unplugged. I don't know why but when I plugged it back in, Trans Failsafe would go off again. It appeared to me that the vehicle was not driveable with the MAF unplugged for this reason.