Update,
I had been babying this car's fuel choices starting out. It really sucks to be stranded on a mail rt waiting on someone to bring you a car to switch out in and then them figure out how to get back home. I didn't want that to happen. I was blaming it's problems on the "sub standard fuel", coking and idling. BUT this car has other issues, I mean it was a 850.00/900.00 junker. (can't remember exactly what I paid, it was definitely less than 1000) it has the common leaking delivery valve problem, worn turbo-shaft and other problems to be expected from a < 200,000 mile car. I was making assumptions and guesses by what I was observing. Now after running about 275 gallons through it with some diesel thrown in between fillings, I'm beginning to change my line of thinking.
The delivery valve leaks oscillate from mild to terrible. Some days it's not noticeable I can only assume its due to the high amount of gear oil I am running as the heavier the fuel the less it leaks. Idling for three or four minutes only leaves a few drops on the ground. On the batches with lighter oils, the leaks are worse, and on D2 they are terrible. So bad, that I notice as much as 1/4 tank of fuel consumption more on a rt when running a tank thats mostly D2, AND puddles of fuel under the car in just a minute or so sitting at a box. The leaks have worsened since I purchased the car, repaired it's most serious problems and put it on the road. After making it road ready, It took me several weeks to build my right seat pedals and put it on the mail rt, where it can see as much as 1400 miles in 6 days. Max mileage clocked in a 7 day period was 1630 according to Vezma. The last two tanks put in the car were 80-90wt gear oil with NO thinner. On these last two tanks it has run like a champ compared to what it was doing. I must note this was clean gear oil from a factory that shut down. We originally thought it to be a heavy weight hydraulic, but have confirmed it to be gear oil.
The problem with my current design in my processor is the fuging tank has it's pickup located high enough to leave 15 or so gallons in it when pumped out. While I did suck the tank out with my super sucker after the batch that I know went into my cars wet it most likely had a little left over to continue contaminating the next couple batches. I am now sure there is NO moisture in the fuge tank.
I have decided the BAD batch of fuel I stupidly rushed into the tanks one day (cause I needed enough fuel RIGHT NOW to fill my truck tank and my car for the hole week) was the largest part of my immediate problems. I am still getting condensation in the filler neck and cap every time I open it when it's cooler out, and have blinded two filters from what I can only assume is from water off that batch. I have purchased a water block filter to add to my finishing filters, but did not have one at the time, and it is still sitting in the box in the shop.
Back to the point though. While there may be some water still in my car, I now feel the fuel going in the last two weeks was dry. In the last two weeks aside from a persistent injector knock at idle it has progressively gotten better, and I am going to refrain from putting in D2 in it until it acts otherwise. The last two tanks were pure gear oil, and the last tank specifically had the car running on pure gear oil as the tank was 50 miles past the refill light when I filled it up. One would assume if it simply didn't like the heavier waste oils it would naturally HATE the pure 80/90 NO RUG added on my last fuge batch It's actions speak otherwise. While on the heavy batch the delivery valves have leaked very little and aside from injector knock it's running great on it.
I called up Mr. Randy Drost from Executive Auto in Blue Springs MO and had him send me another set of valve seals cause my dad inadvertently through them in the trash. While on the phone I explained the cars actions to him without telling him the type fuel it is on and the first thing he said was change the seals. I didn't want to tell him my fuel was out of the ordinary because I didn't want him to do as a lot of other experienced Mercedes mechanics have done and immediately write it off as my fuel choice.
Bottom line is it runs great now with no miss, and good acceleration, and the problem seems to be more linked to the amount of leaking at the delivery valves than anything else. I have been saying I'm going to change them, and the only time I did have a chance to do it I discovered my dad had cleaned his truck out and thrown them away not know what they were. Got another set of washers and seals, and as long as I don't get called into work much this week I'll change them. I will also attempt to find the knocking injector and replace it at the same time.
I'll post and update in a couple more weeks.
, some folks already don't like the mailman, don't wanna give em any more excuses! I do plan on adding water injection, to help combat the nasties.
