MAS/MAF - Unplugging to test ? ? ?

[Mini]

Hi,

After reading this thread a couple of days ago, I parked up at the supermarket, came back and decided to unplug the lead from the MAF to see what effect it has. Started engine and it sounded really weird, like a really loud whirring noise similar to noise of aircraft jet engine (it was actually quite loud), so decided not to drive in case i screwed anything up. After I plugged lead back in and re-started car, it sounded fine again!

Just looking into the MAF thing cos of slight over-revving, lack of power and hesitation.....the usual. But I replaced MAF about 5-6 months ago with Bosch OEM replacement and the MB cant find anything on the STAR diag either!

Any Idea's?

Tried unplugging again the other day, noticed that when MAF is unplugged, the cooling fan starts automatically when the car is started hence explaining the 'unusual' noise from the engine bay. The car was started from cold, so shouldnt be any reason for the cooling fan to cut-in, ehen the MAF is plugged back in and car restarted, the cooling fan remains OFF.

Is this normal behaviour??

 

[BlackC55]

It is normal. It is the endine going in to default mode.