Another MAF Question.

[jblackCLK]

Hi All



I've got a feeling I need to replace my MAF but before I do, I just wanted to see if you agree.


I've got a CLK320 1998 and lately it seems a little underpowered and the fuel consumption has got worse while town driving. (although, its never been as good a official figures even though I’m a sedate driver).
Occasionally when I try to accelerate the car just doesn't seem to respond and even slows down a little as if the engine has been cut. I then have to floor it to get any response out of it and then it'll be fine for the remainder of the drive.

The car also occasional suffers from erratic gear changes, ie I could be accelerating gently from 20 on a flat road and the box won't change up until almost 4K rpm or if I'm on the motorway doing 65 and floor it, the gearbox won't kick down, it will just accelerate in its current gear. Sometimes I could be going slower and it won’t Kick Down.


I’ve removed my current MAF and it is clean and looks relatively new but other than the number RF 280 217 515 and the direction of fitting it doesn’t have any manufacturers name on it (ie BOSCH) so I’m wondering if it is a cheap crappy one.

I’m also thinking it may be worth getting the gearbox fluid changed.

What do you think?

Thanks

 

[panason1c]

Yes, it sounds like an aftermarket maf .... I would renew the maf and definately renew the g/box oil and filter.

ps....No kickdown is a clue that the maf is naf

 

[jaymanek]

seconded

 

[television]

You can always try the car with it unplugged if the car drives much quicker then you have the answer.

Bosch service centers sell them much cheaper than anyone else

 

[LeighW]

Replace it, and make sure it's a Bosch one. Don't waste your money on a cheaper pattern part whatever you do. (Been there, done that).

 

[ibrar]

Hey, sorry to be a nuisance, but what is a MAF and MAS?

 

[jblackCLK]

OK, Ive taken the plung and purchased this

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170183356991

Not a bad price, although similar units for other none mercedes cars appear a lot cheaper.
I toyed with the idea of just getting the Pierburg replacement sensor but the only official info I can find on it only mentions diesels.
So I thought better safe than sorry.

Thanks for the replies

 

[television]

Hey, sorry to be a nuisance, but what is a MAF and MAS?

You could never be a nuisance

They are the same thing S = Sensor F = filter

 

[BlackC55]

If anyone very wants one I can improve on that Ebay price for a gen Bosch item.

 

[mikevernon]

jblackCLK. Television is correct. Don't just replace your MAF (mass airflow sensor) without testing it first, and the easiest way to test it is to disconnect it by simply pulling off the wiring plug. Doing so should put the ECU into an emergency mode in which it will fuel the engine more generously than with a faulty MAF and you will notice the difference instantly.

My experience was with my BMW 330d. The car ran faultlessly but just never seemed to have the punch that I had expected. About 9 months after I bought it I tried unplugging the MAF and the car was absolutely transformed. I measured the 50-70mph acceleration in 4th gear before and after unplugging it, and the time was literally halved down to exactly the time claimed by BMW.

Incidentally, I bought a cheap replacement MAF off eBay and it seemed to work fine. The only problem was that because the engine had run perfectly with the MAF unplugged I couldn't tell whether or not the replacement one was actually making any difference. But the long term fuel consumption was 40.3 mpg and the performance was spot on, so I assumed that it was working fine.

 

[Bazzle]

It is good practice to clean/replace air and fuel filters too.

Bazzle