Drove yesterday 90-miles to San Diego, perfect ride. Went back this afternoon on the same tank: ultra low sulfur diesel from Arco. After driving 1/2 hour fine there was a horrible accident; ten cars involved, was going 5 mph for one hour. After passing the accident I accelerated, I noticed that I had less power then normal, looked in my back mirror and there was a thick cloud of black smoke coming out of my tail pipe. Went off the freeway, looked under the hood; everything was fine, Idled and sounded normal, hit the pedal in N; lots of smoke. Turned off the car, started again: no smoke.

Went on my way, first slow (60-mph), no smoke, after 3 minutes went up to 80-mph, looked like I had more power then ever before...car drove great, only with a driver ready for a hart attack.

My car has some white smoke, visible at night when I accelerate and there is a car behind me; but never black smoke.

Is it possible that the new ultra low sulfur diesel fuel caused this?

I still have a can of Diesel Purge, will use it tomorrow. Got to go back to San Diego monday morning.

Any thoughts?

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1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).

An hour at 5mph could be enough to to "load it up". Itallian tune up time?
jus a thought.

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1959 Gravely LI, 1963 Gravely L8, 1973 Gravely C12
1982 380SL
1978 450 SEL 6.9 euro restoration at 63% and climbing
1987 300 D
2005 CDI European Delivery
2006 CDI Handed down to daughter
2007 GL CDI. Wifes

I've been swapping fill-ups between our local Exxon "classic diesel" and the Arco ULSD up the road. So far my experience with the new ULSD fuel has been positive. Quieter and cleaner. My car gets regular Italian Tune-ups though, running the hill every weekend between Calistoga and Santa Rosa.

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'78 300D 310K Maple Yellow / Bamboo
'87 300D 81K Barolo Red / Safron (RIP @ 113K)
2003 E320 34K Pewter/Charcoal
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My brother's SDL will "lay and egg" the first time you accelerate hard after extensive stop and go driving. I think the pre-chambers carbon up somewhat from low temps while idling, and soot will collect in the exhaust. When you romp on it that first time, it blows all the settled soot out in a big black cloud.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I'm driving this car for one and half years in LA traffic, never black smoke. Is there a way to clean the pre-chambers, or is an Italian tune-up the only way to go?

I don't drive my car like a grandma, more like an "aspiring rally driver" so it gets the tune up all the time.

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1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).

Better get something in there soon to offset the lost lubricity of the ULSD/LSDF or you'll shorten the life of that IP. Adding enough B100 to make a mixture of about B2 should be sufficient. Stanadyne lubricity enhancer will work too.

See this for more info:
LSDF and You

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Never a dull moment at Berry Hill Farm.

An hour of creeping along just off idle can build up a lot of carbon in the prechambers, idling isn't something MB diesels are very happy with. Also makes soot collect in the exhaust from cold combustion.

Hard driving on the freeway will prevent this most of the time, but when you get stuck in nearly stationary traffic, ultra low sulfur fuel is probably worse than "normal" diesel -- the sulfur greatly reduces smoke/soot and evens out the combustion temps at low load.

A fair trade off, as the only result in the car is the need to blow it out once you get free of the stall.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

So you think it has to do with the ULSD?

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1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).

Here is ARCO's official statement on the matter. Does anyone know what lubricity level MB or Bosch required for OM617 era engines? BTW - I pop a couple of ounces of LDL in at each tankfull.

From the ARCO FAQ:

Q: What about lubricity? I hear low sulfur diesel has poor lubricity.

A: Sulfur is a natural lubricant in diesel. As the sulfur is removed lubricity levels need to be monitored. BP uses a specially formulated lubricity additive to keep the lubricity above 3100 grams on the SLBOCLE test, which is the level most engine manufacturers, require in their warranty statements. SLBOCLE (Scuffing Load Ball on Cylinder Lubricity Evaluator).

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'78 300D 310K Maple Yellow / Bamboo
'87 300D 81K Barolo Red / Safron (RIP @ 113K)
2003 E320 34K Pewter/Charcoal
-------------------------------------

But most of our engines are out of warranty and I don't think they tested it on a 25 year old engine like ours.

Next time when I have an empty tank I will put some fresh ULSD in it and go voluntarily for a hour in bumper to bumper traffic to see what happens when I hit the paddle afterwards.

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1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).

Shouldn't matter. If the ARCO/BP figure is compatible with the original MB, or really Bosch, lubricity specs then one would think it would not be an issue. The lubricity requirement is the lubricity requirement. Engines age, regardless. Now, lubricating metal to metal is one thing. Compatibilty with the IP seal chemistry is something the FAQ did not address.

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'78 300D 310K Maple Yellow / Bamboo
'87 300D 81K Barolo Red / Safron (RIP @ 113K)
2003 E320 34K Pewter/Charcoal
-------------------------------------

THis is sorta on topic here, since people are talking about soot buildup with idling... is it better to shut off the engine when you're just doing a quick stop for like 5 minutes, then turn the engine back on? Or is it better to let the car idle?

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1985 CA 300D Turbo , 213K mi

Drop the tranny down to 3rd or 2nd in traffic, if you have a turbo diesel they love this. No loading up.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Low sulfur fuel is gonna make more soot than high sulfur fuel in any conditions that soot gets made, this is one of the things that has to be "fixed" in the engine design as sulfur levels go down. The sulfur trades electrons very nicely, and has a marked effect on combustion.

Low load "fast idle" conditions will make any diesel collect soot, the combustion temps drop too fast for good burn.

"normal" idle (standing) is less of a problem, actually, but it takes very little fuel to idle a Benz for 5 min. I shut mine off since they re-start instantly when warm, but if you have to crank it 15 sec or so to get it to light, you are probably using more electricity watts than the equivalent "wattage" content of the fuel you would burn by leaving the engine run.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!