A couple of weeks ago, I noticed my 2011 R350 Bluetec was having rougher starts. It got worse and worse. At the half tank, I decided that maybe it was bad fuel and filled up at my usual station. The starting instantly got better and better until a few days later, I was driving and lost power. I couldn't accelerate over 40 mph and the transmission was shifting very harshly. I pulled over, stopped the engine, restarted it and everything was back to normal except for the check engine light on the dash.
I called my MB dealer and they said they could not fit me in till next week, but since the car was driving normal, I could keep driving it. But that day on the way home (with my one year old in the car), I lost power again. I pulled over, stopped and re-started the engine then gingerly drove slowly home. Then had the car flat bedded to MB.
Dealer diagnosed it as bad fuel clogging the fuel filter. Replaced the fuel filter and delivered the car. I was unhappy to have paid $365 for the replacement fuel filter, but then thought it was better than a grenaded fuel pump like the VW TDI's have been getting from bad fuel.
Drove to work this morning with no problems (~28 miles). Took the back roads home and half way the engine stalled and I rolled to a stop on a 2 lane road with my kid in the car. Seriously not happy. I did only have 1/4 tank of fuel left, so I thought maybe I needed to fill up ASAP. Drove to the nearest diesel station and only stalled once on the way.... only Filled up 16.8 gallons and I was on my way. Car seems better now... but with that Check Engine light staring back at me I'm wondering what do I do.
I guess I should send the car back to the dealer. Part of me wants to take a fuel sample or read the engine codes before I take it in, so I can have a record of what's going on. I've heard some bad horror stories on the tdi forums. My 2006 CDI gets serviced at my local mechanic. I had wanted to keep servicing the 2011 at the dealer until it was out of warranty. But now I'm worried that this going to turn into something where the dealer wants to replace the entire fuel system. Does that happen with the Bluetec engines?
Sounds like it might be a faulty high pressure fuel pump. No way to be sure until you get the codes read. Even then, I'm not sure if you will get different codes with a failing HP fuel pump vs. a clogged fuel filter. Since they've replaced the fuel filter already, the same codes would almost certainly point to the HP fuel filter. Since you are still under warranty, it would make sense for the dealership to remedy this.
Interesting theory. My own theory has been that I still have the bad fuel floating on the top of the tank and whenever I get down below the half way mark I start sucking crap in. I was wondering if I should put some Power Service Diesel treatment in to get rid of the junk....
I wonder what this "crap" would be...
they would have to be pretty small particles to get through the intake screen of the low pressure pump. Also, a clogged fuel filter doesn't make sense, since this condition would result in a more regular occurrence of your symptoms... a clogged filter once clogged will always be clogged. If you are noticing poor running always at the same time (when the fuel level is low), you might have a problem with the LP fuel pump. In my CDI, the LP pump has failed twice and did not throw any codes either time. This may not be the case in the Bluetec... The HP pump however does throw a code when it fails or is not operating within specs.
In any case, I would be interested to know what the cause was if they figure it out..
Well yesterday's commute home was uneventful. This morning I was only 1/2 mile from home, when the check engine light came on and I lost all power. The car did not stall, though. So I limped home and switched my son into my CDI. You know having problems when you have a kid is a real PITA and kind of nerve wracking because its not just me stuck at the side of the road.
I'll be calling the dealer later today, stay tuned.
Dealer delivered the car yesterday with their assessment that the left fuel rail was beyond spec, delivering 8,500 psi instead of 4,500 psi. Codes 11B800 an d11BA00 were found. The left fuel rail including the quantity control valve was replaced.
Haven't actually driven the car yet. Will take it out tonight when I don't have to worry about my kid.
60 miles from home on Friday night with the family in the car and the Check Engine light came on followed by severe power loss but no stalling. Drove to the nearest station, filled up. Turned the car back on and things got better.
Had the car flat bedded back to the dealer using MBUSA roadside assistance. They really seem to be a lot slower than AAA plus. AAA is usually 30 minutes to pick up the car. Last time Mercedes took over an hour, this time 2 hours.
Haven't heard anything from the dealer yet, although they did send a 2012 R-Class loaner. Its amazing what they changed in one year knowing they were going to stop selling it. New engine, different buttons on the tailgate, different headlight switch, LED front lights instead of the fogs. Couldn't get them to turn on as fogs. Very strange.
The new engine is much more powerful than the old gasser around town, but on the highway it feels winded compared to the Bluetec. I really had to floor it to get it moving, whereas the Bluetec just goes, well when its not in limp mode.
Got my call from the dealer. Diagnosis is bad fuel which caused rust and corrosion of the fuel system. They need to replace the fuel tank, fuel lines, fuel pumps, rails, etc... the entire fuel system. The supposedly spoke with Mercedes of America about it and they're not covering it under the warranty with 29k on the car. They want $12k to fix it.
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