impee's DIY Mass Air Filter Sensor (MAFS) Clean

DIY Mass Air Flow Sensor (MAFS) Clean

impee's DIY MAFS Clean for BMW 318i e46
How to Clean the Mass Air Filter Sensor yourself!

Difficulty Level: Easy

Approximate Time For This Project: 1 hour

Prices: Professional labour costs for MAFS clean - £35 (private) or £155 (BMW) - per hour X 0.5 hours

REQUIRED ITEMS
items	INFORMATION	OUTLET	QUANTITY	PRICE*
Electrical Contact Cleaner	or a MAFS cleaner	http://www.halfords.com	1	£5.99
Screwdriver	Flat head bit	http://www.halfords.com	1
Socket Wrench	+ extension bar	http://www.halfords.com	1
10mm Socket		http://www.halfords.com	1
10mm Spanner		from your BMW tool kit	1

*prices correct at time of publication

1)	Assemble Your Kit + Notes
	Below is the total kit I used. As you can see, there aren't many tools required for this job at all. Change Duration: The Mass Air Filter Sensor (MAFS) should be cleaned no sooner than every 20-30k miles. *Note:* If your car is not exactly the same model as mine, please the sensor may be different and also attached differently.

2)	Engine Cover - Removal
	Remove the main big BMW cover (Intake Manifold) at the front of engine using this method:
1)	Remove the 2 clips at the front - pull up and then out the small round black pins (expanding rivets) with a flat head screw driver
2)	Un-clip the hook on the top left
3)	Remove the large hose on the top right

3)	The Air Filter Housing, Intake Silencer
	This is the housing for the Air Filter, the Intake Silencer. It is best to remove this to be able to get the MAFS out. Use a 10mm Socket to open the 2 nuts.

4)	Wiring Plug To Take Off
	Press a small clip on the plug and pull of the Wiring Plug.

5)	Intake Hose - Removal
	Loosen this screw with the Flat Head Screwdriver and then pull of the big hose, the Intake Hose.

6)	Intake Silencer - Removed
	You can see the Intake Hose and Wiring Plug unplugged. Also in this photo, see the arrow...this is pointing to the location where the Vacuum Hose fits - this is a thin black rubber pipe. As you can see in this photo, mine had come off, hence when you are putting everything back together, ensure you fit the Vacuum Hose back in!

Intake Silencer - Removed

You can see the Intake Hose and Wiring Plug unplugged.

Also in this photo, see the arrow...this is pointing to the location where the Vacuum Hose fits - this is a thin black rubber pipe. As you can see in this photo, mine had come off, hence when you are putting everything back together, ensure you fit the Vacuum Hose back in!

7)	Intake Silencer - Removed
	The Intake Silencer removed.

8)	Removing Mass Air Flow Sensor (MAFS)
	Use the 10mm Spanner to remove the 2 nuts. Then pull of this circular item, this is the Mass Air Flow (MAFS).

9)	Mass Air Filter Sensor - Dirty
	The Mass Air Flow Sensor (MAFS) may may not appear to be very dirty, but trust me, it is. The 2 small arrows at the bottom point to 2 security screws (which I did not have the bit for and could not remove) that hold release the MAFS. As I could not open them I cleaned the MAFS whilst it remained fitted. Spary lots of cleaner everywhere inside and specifically into the 3 long arrows, as they are the main sensor parts.

Mass Air Filter Sensor - Dirty

The Mass Air Flow Sensor (MAFS) may may not appear to be very dirty, but trust me, it is.

The 2 small arrows at the bottom point to 2 security screws (which I did not have the bit for and could not remove) that hold release the MAFS. As I could not open them I cleaned the MAFS whilst it remained fitted. Spary lots of cleaner everywhere inside and specifically into the 3 long arrows, as they are the main sensor parts.

10)	Mass Air Filter Sensor - Clean
	It already looks a lot cleaner. Let it dry before you fit it back, then if you want at the end, use a cold hair dryer to make sure it is dry.

10)

Mass Air Filter Sensor - Clean

It already looks a lot cleaner.

Let it dry before you fit it back, then if you want at the end, use a cold hair dryer to make sure it is dry.

11) Re-assembly

Now work in reverse order following all the above steps.

Ensure you put back the Intake Hose, the Vacuum Hose and then tighten the Intake Hose clip and also plug back in the Wiring Plug.

Take the car for a test drive and you will notice it to be alot smoother and responsive than before.

11)	Re-assembly
	Now work in reverse order following all the above steps. Ensure you put back the Intake Hose, the Vacuum Hose and then tighten the Intake Hose clip and also plug back in the Wiring Plug. Take the car for a test drive and you will notice it to be alot smoother and responsive than before.

DIY BMW e46 Mass Air Flow Sensor (MAFS) clean by - impee www.impee.co.uk

Any questions please contact me