MAS part numbers and the How To.... Diesel and Petrol the same?

[dougl65]

I substituted the Bosch part in my C240 with the Pierburg part from my straight six S320 cdi to diagnose poor running problems!

Referring to the "How to" here

http://mbclub.co.uk/forums/showthread.php?t=25426

I am a little confused as to using the Pierburg MAS as a replacement for the original bosch part.

The Pierburg part number is listed as 7.22684.07.0

According to Pierburg this is a replacement for their own unit part number 7.22684.00.0

See here

http://www.x-desk.net/ximages/21302_pgsi0079en.pdf

The "how to" suggests that this is the replacement for the original Bosch fitment in the M112 V6 engines part number A112 094 00 48 however the Pierburg pdf states that this is a replacement for the A611 094 00 48 which is actually the OM611 diesel engine. Note that the last seven digits are actually the same, the first apply to the motor code!

Funnily enough if you search for the German and Swedish part number (18789) on their site it gives the Pierburg component as the replacement for a Seat Ibiza diesel!!!

I HAVE actually replaced my original Bosch sensor in my C240 V6 with the Pierburg unit and it seems to work fine. Are the diesel and petrol MASs the same in real terms? It would appear to be so!! Sorry about all the confusing part numbers but it would appear that Pierburg DO NOT actaully make a direct replacement for the M112 engine as described in the "How to" although it actually seems to work

 

[grober]

Theoretically speaking the MAS sensor is measuring AIR flow into the engine which is the same no matter what fuel is being used. The engine ECU will interpret this "raw data" in different ways but basically its the same type of measurement in both engines. These sensors are used by a wide variety of manufacturers so its not surprising they are found in other cars. I agree its a nightmare trying to wade thro the part nos. Further confusion arises if you are talking about the entire unit( housing +element) or just the element itself.

 

[dougl65]

Theoretically speaking the MAS sensor is measuring AIR flow into the engine which is the same no matter what fuel is being used.

That is exactly what I thought. In other words as long as the sensor fits the housing it should do the job, even if the measurements are slightly out of spec!

Replacing this cured all my running problems despite the symptoms not being directly traceable to the MAS such as:

Intermittent starting hot or cold
Occasional idle instability or surging
Engine cutting out when coasting to a halt

The final symptom which led me to replace the MAS despite it being less than a year old (it was a brand new corrct BOSCH part purchased on Ebay) was a certain harshness and reluctance to select or change gear!

 

[Shude]

That is exactly what I thought. In other words as long as the sensor fits the housing it should do the job, even if the measurements are slightly out of spec!

Yes, it seems likely that the actual sensor in the MAS assembly is the same for a large number of models but that the pipework it is attached to is specific to a particular engine or car model series.