MB 270Cdi Auto power loss

[simon watson]

I have a MB 270Cdi which shuts down to 2000rpm when 'kick-down' is used.It resets itself after 15-20mins with ignition off.Dealer has changed complete exhaust system inc both cats and the problem is still there.I suspect the Turbo..Anybody had the same problem?

 

[jberks]

When you say 'dealer', is this an MB dealer? It seems odd that they can't resolve it. It's gone into safe mode and whilst there are occasions where the fault code is not stored or incorrect, it's rare. Do they have the code? - if so, let us know what it is. The MAS sensor is the most obvious cause but I am assuming they've ruled such things out already.

 

[psmart]

Just replied to your other post, where I didnt see the Kick Down issue.

On my ML, the lock down would occur in kick-down, ie. floor the car and hold kick-down for a while, lock-down would occur because of the Boost Pressure Actuator Transducer. In my experience though, you would get 3000rpm or 85mph max in 5th gear.

As per JBerks, have you got any fault codes (ask the dealer)?

 

[simon watson]

I will try to obtain code(s) tomorrow from the MB dealer in Gibraltar.As over £1000 has been spent so far with them replacing the wrong bits hopefully they will help!What do you think about the turbo overboosting which would shut the engine into safe mode?OR the wastegate jamming which might also have same effect?

 

[television]

From all of the postings it would seem to be the MAF, the turbo does not shut it down to 2k revs. The MAF or MAS what ever you want to call it would appear to have a shorter life on diesel's than petrol, 60-70k being the norm, the reason being that diesel is more oily the petrol allowing dirt to stick to it.

Malcolm

 

[simon watson]

MB 270Cdi Power loss

Thanks Television!This car is 3 years 8 months old and has only done 50000 kilometers!! I will come back with more info tomorrow night.

 

[psmart]

This car is 3 years 8 months old and has only done 50000 kilometers!!

31000 miles, and not even 4 years old..... sounds a little suspicious for the Exhaust, MAF or any other part to have gone due to wear and tear.

The Air Sensor uses a thin wire heated element to detect air flow and is supposedly protected by the air-filter, so unless you've got a holey filter, shouldnt have gone at this age. Also, you mention that once the car has had a cool down, it goes full throttle again. Analagous to an electronic circuit, I'd be spraying freeze spray on things like the MAF, BPCVT (I call it BPAT, but its actually the Boost Pressure Control Vacuum Transducer) etc and seeing which, after spraying freezant on, allows the engine to restart immediately after switch-off.

What do you think about the turbo overboosting which would shut the engine into safe mode?OR the wastegate jamming which might also have same effect?

The Turbo on these engines is a variable vane unit, ie. no wastegate. The vanes are engaged according to vacuum pressure, which is modulated from the Vacuum pump via the BPCVT. If the BPCVT were to go faulty, or the vacuum piping/pump were to go faulty, then Turbo wouldnt spin up. As mentioned to mouldb, see if the Turbo whistles when it goes into the 2K mode, you should just be able to hear it. Rightly, if the MAF has gone, then the ECU will disable the BPCVT, but I think gathering as much data will give us more to go on.

One other thing, when it goes into 2K mode, select Neutral and rev it hard - see if it goes beyond the 2K limit. Also see if this is the case in each gear. This is just to establish a possible reason, ie. if it is the engine, or possibly the gearbox (torque convertor fault etc).

When I had the BPCVT fault, it would max out at 3000rpm, but knock it into neutral and it would redline, this is because the engine torque was much reduced, not having the Turbo.

 

[simon watson]

Thanks Psmart for ystdys last thread.Today have been to MB in Gibraltar who have the code(which is Classfied) and they have sent this to MB Espana in Madrid.It is the same code that made them change the exhaust system and the cat.They have changed today(just to try) a turbo air sensor which is both air and electrically fed.This is a small part in the front LHS of engine area near air mass meter.(which THEY say cannot be faulty!)

 

[psmart]

Left Hand Side, opposite to the MAF, just down from the spherical ball is the BPCVT, two pipes go in at the top, 1 pipe dangles at the bottom with what looks like a fuel filter! Is this the device?

If its faulty, code read out is P1470.

Code classified..... there trying it on, to hide there incompetence, or worse, their theft! You could try another Merc garage or indepent.

 

[watsone91]

I would do a system reset with this fault disconnect the battery for 5 minutes then recconect bearing in mind it will play havoc with your central locking and alarm set up hope this helps cheers.....

 

[psmart]

This thread gives more info on the MAF fault....

http://forums.mercedesclub.org.uk/showthread.php?t=12659&highlight=flat+spots

Sound familiar?

 

[simon watson]

Hi everybody...latest from the MB dealer in Gibraltar is that they have now been told to look for an air leak...! Thats it! I will have more info next week when they start working on the car again....