Lack of top speed!

[vito dazza]

i have an on going problem with my vito 108cdi, the van will not let me go past 70mph for any period of time. When i start the engine i have full power and i can get 60-65 in 3rd at max revs i can also rev it out in 4th but when i change up to 5th the van hits about 82 for 10 secs or so and then loses power and drops into safe mode. Full power is resumed after switching off the engine for 10-15 secs. The van has been back to MB who charged me £70.50 for an hours labour to check for fault codes and told me to try cleaning the air filter (K&N). Not happy! The other day a friend had a look at it and went for a drive down the motorway, when we got to 70 in 4th he changed up a gear WITHOUT THE CLUTCH and the van ran on to 110! but when he slowed down and tried to accelerate again the van stopped at 70????? NOW I'M PUZZLED!:-?

 

[Sprint'n'Go]

Full power is resumed after switching off the engine for 10-15 secs. The van has been back to MB who charged me £70.50 for an hours labour to check for fault codes and told me to try cleaning the air filter (K&N). Not happy! The other day a friend had a look at it and went for a drive down the motorway, when we got to 70 in 4th he changed up a gear WITHOUT THE CLUTCH and the van ran on to 110! but when he slowed down and tried to accelerate again the van stopped at 70????? NOW I'M PUZZLED!:-?

It is certainly a puzzler, but I would start by substituting the air filter back to the factory set up. Perhaps this is causing the ECU to receive misleading airflow/air temp readings particularly as I presume the K&N filter picks up the air from within the engine bay where as factory filters normally have ducting to the outside or down to near the bumper where they can pick up clean cool air.

I don't know if your van has a MAF sensor in the pipework but if it has it could be worth checking its condition and cleaning it. Follow Parrot of Dooms excellant 'How To' at the top of the engine and drivetrain section of the forum and pay particular attention to the cleaning agent used.

As to why your vito is only going into limp mode at speed perhaps it could be something to do with heat generation and airflow when moving faster?

As I said, first I would try going back to the factory filter set up.

Hope this helps.

 

[vito dazza]

The K&N filter has a cool air duct running from the front grille, filter has just been cleaned and has been on the van for about 18 months without any problems, my vito does'nt have a MAS sensor fitted to it. Is there a speed senor that could be out of sync? if so then can it be reset?

 

[opps-man]

The K&N filter has a cool air duct running from the front grille, filter has just been cleaned and has been on the van for about 18 months without any problems, my vito does'nt have a MAS sensor fitted to it. Is there a speed senor that could be out of sync? if so then can it be reset?

If you have a CDi engine then you most certanly have a MAF sensor,
The fault that you are describing is the Boost presure controle vacume transducer, this items tells the turbo gate valve how far to open,
If the gate valve is "over gating" then the ECU will go in to limp mode, this can be driven through before the signal goes to the ECU, but when you try to cruise at around 3000 rpm the engine will go in to Limp Mode.
Get this checked out at a performance garage that can put your car on it`s diagnostic computer.
I had the same fault on a C220 CDI, and the fault caused the premature failure of the turbo unit as well as the above mentioned controle unit.
Cheers
Don.

 

[sul]

anyone know where this maf sensor on the vito is located
cheers

 

[dvarley]

where is the engine temperature sensor on the vito 110cdi the gauge is reading hot all the time, consequently affecting the running of the engine. both fans are constantly on also

 

[toxic]

K & N filters are very good on Mercedes engines been told this and read it many times ...not sure why