A170 CDI Semi Auto NO POWER

[punitsu]

I own a A170 CDI semi auto 1999, recently i noticed that the car lacked power (high revs, slower acceleration) in all gears. It runs fine for the first 5 - 15 mins (cold start) once the engine has heated up it struggles. causing problems on motorways when picking up speed/overtaking. When the problem occurs it only picks up speed when revs are on/over 2500 rpm.

130,000 miles on the clock

if any further information is needed please let me know

please help

 

[Robbruce]

Hi When my C270 had the similar problem turned out to be the MAF sensor.

 

[punitsu]

thanks for your reply, is it a easy fix? how costly?

 

[AndyPCD]

If i remember correctly i think they are in excess of £700 as they are part of the ecu.
Would be worth getting it stuck on a star machine to get the fault codes read first

 

[Rogan]

I have the same problem. The engine is fine after a reset, but the problem reappears when it gets to 3rd gear. No errors are showing and the car itself is dandy. Seems to be a dirty MAF sensor, which should be an easy fix.

However I've got no idea how to access the air filter to get in and give it a squirt of carb cleaner.

The only pictures I've seen are of the petrol with the MAF on the RHS of the bay, on mine the MAF is on the LHS, and it uses the more standard separate sensor assy. Would someone be kind enough to explain how to open the air box?

To me it looks like you have to undo a load of star headed screws, but it looks like the fuel pump is bolted through the same cover. I'm pretty sure you wouldn't have to unbolt the fuel pump to get to the air filter, so... heeeelp!

 

[npuk]

The MAF sensor can be repaired. For info see: Bert Rowe's-Mercedes-Benz 'A'-class info. Mass Air Flow/ECU problems and the alternative to purchasing a new unit costing £1200.00 + Fitting from Mercedes-Benz, Special discounts available to readers of this site on guaranteed repairs.

 

[Rogan]

Cheers, just ended up popping it out the housing and blasting it with carb cleaner.

Papped myself because I thought I'd dropped the temp sensor from the side into the engine. Seemingly it's optional and would just never have been fitted.

Looking forward to going back to fixing cars that can be repaired with a lump hammer.

 

[Robbruce]

Hi Mine is on its own in the air tube into the air filter box and only cost £100 fitted

 

[Rogan]

I just tested mine and the resistance was about double what it states on the datasheet. Looks like I'm in the same boat. Fortunately it's not my car.

The embarrassing thing is my mother has been driving with this problem since the car was new.