Hi All,

I've searched for my issue but not found a resolution or something exactly similar, although it might have been dealt with in the past. I've had the car 5 years.

Problem: When accelerating i get a feeling/feel from the car that its hesitating to go into turbo at approx.1600 rpm if you accelerate slow enough, if I put my foot through it you cant feel it however there appears to be no real "go" when accelerating. in the past I've always felt there be boost in gears 1-2 when flooring it - now it just kinda feels a bit flat. If i was to hazard a guess it would be that the turbo isn't opening up properly but i know very little about cars!!

Things Observed/actioned: Ive checked for signs of "black death" form the injectors but nothing doing. My dads cleaned the engine down, changed the fuel pump and ran injector cleaner through the system. After picking it up from him after i got onto the motorway and was half way home and then as i hit 70... limp mode.... took it back to my dads next day - we disconnected the ecu and made sure everything was as dry as could be from the cleaning and then I ran it up and down a slip road on the motorway and absolutely ragged it up and down and found no issue, no limp mode and it actually felt back to normal - took it home and it was fine for maybe... a fw days and then i started to feel as if the problem ws returning and then on my drive to work this morning i could hit it everytime on approx. 1600 revs.

Not quite sure what the issue might be so looking for advice. The only fault code was a common one ( i dont recall for now) about cylinder 1 not reaching the emergency position (or something similar) but when i looked it up it could be common and ignored - this was also coming up prior to the issue but like a long time before.

Thanks in advance.

 

Only advice I can give from what you have already checked and done is check the condition of your DPF.

The symptoms you describe do sound very much like the DPF is getting close to max silt build up and needs servicing/clean.

Also do you have your own diagnostic tool, it's a sure method to identify such things, I've got one with MB specific software for my C Class and am able to find most probs that exist and also action a fix if it allows rather than the doing the trick of turning off power to reset the ecu. Some minor errors/codes will but a lot of other probs/errors will persist and stay logged within the ecu and not clear by simply turning it off and on.

All else failing the next obvious step is taking it in to a dealer for service/fix or other MB tech service workshop.

 

Hi
Thanks for the advice. My dad has one of those hand held ones with the "circuit board" style keys for certain cars. We've checked the faults and reset it after last time - the ECU disconnect was just because there may have been some residual water in the connectors which caused it to go limp.

I'll see if he fancy's cleaning out the dpf...

 

No probs, certainly check it out further as poor health/condition of DPF's and associated sensors to them are a main cause of limp mode.

Physically cleaning the DPF is quite the task even the simple DIY of feeding in the cleaning fluid and then running the engine until it's dried out is laborious...and you have to be very careful not to damage accessory components which need to be removed and reinstalled.

I researched the above extensively do try on mine, but gave up because of the time/complexity and just took it to my MB tech workshop, where they physically removed the whole thing and cleaned it thoroughly over a 3 day process, the cost was not that bad in the end and have had this done twice so far. Much cheaper than the thousands of $$$ required for a new DPF.

You can also successfully clean up a clogged DPF with an appropriate diagnostic/actioning device - if the one you have does that, it will require a very long constant drive at a certain speed/rev range, I've tried this once also (before the 2nd time I got mine removed and cleaned) and it worked ok, but after a prolonged 1.5 hr drive the silt/soot reduction was less than half what it needed.

All the best with it if it is indeed the DPF that's causing your problems, if so then once it's cleaned it'll remain problem free for years

 

I've put some wynn's DPF cleaner in the tank and taken it for a drive up and down the motorway for 30 miles and it seems not to stutter but i still dont think its optimal. I'll come back to this thread if i get it resolved completely. My dad also advised he can engage a manual regen from the device he has so maybe i'll see that at some point.

 

Well it was the boost hose!! Replaced and all back to normal.

Take a look