MAS - Some interesting observations

[se97mlm]

Dave, how much did your fuel consumption improve by? From what mpg to what?

Don't want to count my chickens, but it would be great if i got better economy too!

Have to stop enjoying the new found power first though i suppose!!!

 

[rees_A]

I had a new MAS fitted last week. Perf is better but have developed another problem now.....When accel from standing start, can't stop the wheels lighting up...Guess I have proper power now..lol... Ayway, can't say I've seen any difference in economy so far, will have to wait till the tank is empty to be sure(first 1/4 lasted 72 miles as usual(The rest lasts another 110 normally)

Al

 

[se97mlm]

gosh rees, that's really thirsty!! 15mpg?!

 

[Dave Bailey]

Dave, how much did your fuel consumption improve by? From what mpg to what?

Don't want to count my chickens, but it would be great if i got better economy too!

Have to stop enjoying the new found power first though i suppose!!!

Once I'd stopped enjoying the power (difficult, it is a bit addictive....), the fuel consumption went from 24-28 mpg to 28-32 mpg with 35 possible on a run with very gentle acceleration etc. There is variance because my daily journey pattern is mixed. Some days it's all long run stuff, on other days I might do a 40 mile round trip with a sizeable urban driving content.

 

[GregE240]

I've read that this problem is limited to mainly the C class - is this true?

Sadly not.....both the V6 and V8 engines suffer from this symptom.

My E240 MAS failed at 98K.....(although same engine)

Greg

 

[C43AMG]

Job,
I recently put my car on a rolling road, the results where 217.1 HP to the wheels which equates to 289 BHP at the flywheel. Would you think a failing MAS as the problem for the lack of BHP as it should have 306 BHP?.

Regards,

 

[jgevers]

Job,
I recently put my car on a rolling road, the results where 217.1 HP to the wheels which equates to 289 BHP at the flywheel. Would you think a failing MAS as the problem for the lack of BHP as it should have 306 BHP?.

Regards,

Hi,

In my experience rolling roads are reasonable for comparative measurement when engine changes are made or for 'setting up' purposes. For one of power measurement there are too many variables like tyre slip, roller slip etc.

Engine power will vary with petrol quality, air density etc. On top of that, most engines will have slight power differences anyway because of running in differences, production tolerances etc. Providing the vehicle drives correctly I wouldn't worry too much. A slight voltage drop in air mass sensor voltage can result in a powerloss though.

regards,

Job

 

[C43AMG]

I checked out Ebay they are selling Bosch Mass for £99.99 + £6.00 postage Mercedes Boxed, i checked the Part No they gave for the C43 with the stealership which is correct, there price £280.00. Ebay Item No 4565064012. They have some at £95.00 for the other Cclass's. So for £100.00 it seems a great buy, if there is no difference i will keep the Mass as a spare.

 

[jgevers]

I checked out Ebay they are selling Bosch Mass for £99.99 + £6.00 postage Mercedes Boxed, i checked the Part No they gave for the C43 with the stealership which is correct, there price £280.00. Ebay Item No 4565064012. They have some at £95.00 for the other Cclass's. So for £100.00 it seems a great buy, if there is no difference i will keep the Mass as a spare.

That's what I would do if I was in your place. Good luck

regards,

Job

 

[C43AMG]

Job,

Many thanks.

 

[nickmann]

Well, dropped the car in yesterday for the reset.

Prior to that, I had noticed that on initial fitting the response had improved, and the gearchange was better. That had become less noticeable over the course of a week or so. I had put that down to me just getting used to it. When the autobox started fluttering between 3rd and 4th again I realised that it wasn't just me getting used to it, the car was learning it's old settings back again from the other sensors.

When I picked it up I had a chat with the workshop. They said they had difficulty in getting the ECU to notice that it had a new MAS. In the end they had to reset everything several times, but it worked in the end. Whatever that means.

The result is even better than it was when I just dropped the MAS in. Response and power are up, changes are sweet. Coupled with the alignment they did, it feels like a new wagon. luvly jubly.

In a week or two I'll know if it stays that way. By then I will be in the South of France - yippee.

 

[Bazzle]

I've read that this problem is limited to mainly the C class - is this true?

SLK 230 is another

Bazzle