Am I right if I say that the MAS sensor ...

[Msmax]

Please help me out with this.

Have read a lot about the MAS sensor giving all kind of problems.

But is it true that for diesel engines ONLY the CDI types have these fitted?

Seems the TurboDiesels don't have one.

 

[Steve_Perry]

I'm afraid I only know a little about the MAS as fitted to petrol units. Maybe Dieselman will be able to help you?

S.

 

[jimmy]

My C250TD has a sensor on the top charge pipe that runs along the top of the radiator, it is a air temperature sensor. Slightly different to a MAS sensor.

I don't know about the CDi engines I'm afraid.

 

[Dieselman]

E 300 turbos deffinately do have a MAS.

All electronically controlled diesels or petrols need a method of knowing how much air is being drawn into the engine.

Older petrol EFI units used to use vane type air flow sensors but they can't account for air density, so the MAS was born.

 

[Msmax]

Hi Dieselman,

Mine is a E-290 TurboDiesel. I checked under the hood and I think I found it.

This sensor is mounted between the air filter and the turbo.
A temp sensor is mounted between the intercooler and the inlet manifold.

Is there a way to test the sensor?
When should it be replaced?

 

[Dieselman]

I'm sure Bosh has given guidelines for testing the MAS but you would need a variable airstream and temperature and then measure the output. In reality there is no test.

Replace the MAS if the car has no go and isn't fuelling up.

 

[Dieselman]

Info for all 200 / 230 owners.

It should be possible to use the MAF for a VW 2.0 litre petrol. Bosch no. 06A 906 461A.
Price about £50.