Got round to the dubious task of cleaning the MAF last weekend.

Found some Servisol IPA 170 (Isopropyl Alcohol) in my local Maplins. Tested a small amount on a bit of plastic before hand, left no resedue and did not melt the plastic, which is always a good thing me thinks. Sprayed generous amounts in all areas, a quick shake and all the spray evaporated immediately leaving one clean MAF. Finised off with a quick blast with an air line.

The RS feels a lot smoother at top end and holds boost a bit longer according to my new boost gauge.

Air Filter... But what does the M stand for?

Mass.

(See you all in church. )

Originally posted by Quinten in this post

Air Filter... But what does the M stand for?

Mass Air Flow Sensor, in between the air box and the DV.

Des

LOL. Not even close then

Now I only have to find out where the air box sits and if DV is the Diverter Valve or Dump Valve...

Diverter Valve.

Originally posted by Quinten in this post

LOL. Not even close then

Now I only have to find out where the air box sits and if DV is the Diverter Valve or Dump Valve...

I know a good book.

I know, I know... I'm really keen on learning more, but I find reading about these technical things just plain boring... Now if there where pictures...

Sounds like you need a copy of the Sport, Q!!

Originally posted by Quinten in this post

LOL. Not even close then

Now I only have to find out where the air box sits and if DV is the Diverter Valve or Dump Valve...

What you need are some pictures.

The Mass Airflow Sensor is labelled "MAS" at the bottom left here, and the DV is labelled "BOV" (Blow Off Valve - which isn't strictly accurate):-

http://www.briskoda.net/members/klb/pix/18Tblockdiagrampic.jpg

The air box is on the right of this cutaway; the turbo is hidden behind the block, and the intercooler is on the left.

http://www.briskoda.net/members/klb/pix/engine_cutaway.jpg

Thanks Mike, that does make things a lot clearer.

Sounds like you need a copy of the Sport, Q!!

Ah, yes, that brilliant piece of journalism that goes as a sportspaper but really is like page 3 in the Sun on every page Got to admire the guy who came up with the name for it...

Thanks for the link Mike - that first one is a really useful picture!

Des - how did you know your MAF sensor needed cleaning?

I agree, that's an excellent "London subway"-style graph of the engine! Thanks, Mike

Originally posted by DaveU in this post

Thanks for the link Mike - that first one is a really useful picture!

Des - how did you know your MAF sensor needed cleaning?

Just doting the T's or is it crossing the I's, Cruise Control next, gulp.

Des

Quinten - if you've ever heard of a hot-wire anemometer, that's basically what the MAF is. It consists of a platinum wire across the inlet with a voltage applied across it, which heats it up. The current of air rushing past it applies a variable cooling effect according to the volume of air (which translates to speed in a fixed size aperture) and thus cools the wire, affecting the resistance. This in turn varies the current through the wire, which is measured to give an indication of the airflow.

MAF's don't last for ever and are expensive to replace. Any cleaning should be done with great care.

:cheers:

You mean my squirt of Fairy and a scrubbing brush method was probably a bad idea? :(

You don't want to leave any contamination on the wire as when heated it will cause oxidation and shorten the life of the wire. I don't know about VAG ones but the Porsche ones undergo a "burnoff" cycle when you switch off the ignition to burn off any deposits on the wire. The more grot on the wire, the greater the toll on it that this burning off exacts.

Ours are the film type.

Ideal for the scrubbing brush treatment

This is exactly why I will always be a sucker for garages... Too many things can go wrong due to my 'handywork'...

I bow to superior knowledge - hot wire ones are probably very passe Must read up on film MAFs...

Nick, the unit we have is a Bosch HFM5 hot-film air-mass meter. If you'd like a diagram of it, see below. Picture taken from "ME-Motronic engine management technical instruction manual, 1999 edition"

Just in case you can't read the text:

1. Electrical connections

2. Electrical terminals

3. Evaluation electronics

4 Air intake

5. Sensor element

6. Air discharge

7. Casing

May I have the sad git of the day award now?

:sleeping:

:nono: