Two simple jobs done.. now WON'T START 2.0 hdi

[Sol]

The thing is, that MAFs are hot-wire anemometers...so the ECU heats a resistor to a "known" temperature, which directly sets it's resistance. The airflow cools the resistor, altering it's resistance back in the opposite direction. From that value, the ECU calculates the air mass flowing over it. (Also taking ambient temperature into the calc using the IAT sensor)

So...dirt on it has zero effect on its measurement ability. Hence, cleaning a misreading one is pointless. If the hot-film resistors' base value has drifted through age, then no amount of cleaning will bring that value back.

[bertylingodave]

Yeah - cleaning MAFs is an internet myth. It does nothing.

I found this as well, I tried acetone and airline. He could help by telling us what he cleaned the MAF with it might work for someone else you never know.

The innards of the MAF were very dirty, both sensor and mesh. Oily -sticky residue present, that enabled clogging on the fine mesh. I cleaned it with Carb Cleaner for what its worth. I also cleaned the fine mesh in the MAF with a jet of Carb Cleaner too, and gave the airbox and airfilter a good clean with a vacuum cleaner.

All I can say is, when I first tested the car with the MAF connected it struggled at 20km hr and could do more the 2/3000 rpm. Disconnected it took off like a bullet. Its doing the same now connected but cleaned. I don't know enough about the MAF as an integral unit to comment, other than transmit my observations.

Dave..

[Sol]

I have to say the only time I've seen one truly contaminated was with a foam air filter where it gets oiled, and the oil eventually covered the MAF and cooked onto the heating element.

I guess you found one that also responded to cleaning.

[bertylingodave]

I guess you found one that also responded to cleaning.

It appears to have done! I was rather nervous reconnecting after cleaning though, as I was fully expecting another limp type experience. To say I was somewhat pleased that wasn't the case is a bit of an understatement to say the least.. haha..

[ffrenchie]

I have to say the only time I've seen one truly contaminated was with a foam air filter where it gets oiled, and the oil eventually covered the MAF and cooked onto the heating element.

I guess you found one that also responded to cleaning.

The one in our car looked perfect but when it was connected it wouldn't manage more than 3000 rpm. I tried carb cleaner first and then acetone with a brush and blowing with air but it was FUBAR and would only run disconnected till I replaced it. Cost me £35 for a new one.

[Sol]

Yep, if they look clean then cleaning is pointless ffrenchie. I noticed the same many times.