hi there,

my car (W205 2014 C250 Bluetec) has had an issue for about 5 years now where it would randomly go into limp mode while driving. We figured out it was the DPF being blocked but i didn't have the money to fix it until now so its been driving like this for 5 years about.

I took it in to a local well renowned tuning shop which has a great warranty and lots of different speed and racing trophies and stuff because they also do repairs. They told me they would delete the DPF, custom forge a new downpipe, and do a tune on the car to make sure everything is running smoothly

Everything was going well until it came time for the tune, and the guys could not get the car to produce boost at all. But when it was driving on the blocked DPF, it still occasionally boosted when it wasn't in limp mode even if it the turbo lag was very bad.

This tuning shop now is saying the next step to move forward is to remove the turbo and send it in for inspection, possibly reconditioning it if needed. But they are also saying that the turbo might not be the issue and the only way to find out is to complete this inspection. But i already paid them a lot to do the downpipe and software and i don't have the money to send it in for inspection and then possibly pay even more if it does need reconditioning or if its another big issue somewhere else. Another turbo specialist shop I found quoted me about 1/3rd of the price to recondition my current turbo vs the tuning, and I'm much more inclined to proceed with as I can actually afford that. But that doesn't guarantee it will fix the boosting issue.

So i need some second opinions. Is it possible for the DPF delete and downpipe to cause this loss of boost, even though the car boosted last week albeit with the blocked DPF and the risk of entering limp mode? And what should i do next? And is there anything i should keep in mind when speaking to these shops?

 

First thing, the DPF system repair would have been covered on MB Repair for Free. Why Free, because all Mercedes DPF's have a Class Action connected to the EPA and Environment Canada.

My wife has the same issue in her GLK 250 and when we brought it to MB to repair it the look up the recall and replaced they entire DPF system with a new one with newer design.

PS, if you want to ruin your Mercedes DPF system, it's easy, use non MB branded DPF fluids and keep the fluid in your trunk and in sunlight. If you can smell the DPF fluid and it's smells strong, it's also gone bad and will clog the system. MB DPF comes in a box which protects it from any light getting to it.

Also, Turbos need some down pressure but even if you can't see your turbo boosting, it's always spinning when you step on the gas. Did you get any errors on the dash for the turbo?