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  #1  
Old 12-01-2003, 09:31 PM
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Location: Orlando, FL
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Black smoke with sluggish acceleration

What is the problem with my 1987 300SDL (198k miles)? -
While driving around town I noticed black smoke from the tailpipe during acceleration and
corresponding reduction in acceleration performance with the black smoke. Since I had
not done any highway driving in for awhile I took it up on the interstate to "blow out the
carbon". The black smoke did not stop but was greatly reduced so I figured all was
better. Two days later I drove from Orlando to St. Pete and about an hour or so into the
trip the 'problem' started again - black smoke with sluggish accelerating. I drove on to my
exit and when I stopped at a red light the car stalled. It would not restart at that time. The
MB Roadside Assistance arrived about 45 minutes later and when I tried to start the car,
of course, it started. I drove, without a 'problem' to the MB Dealership where the
diagnosis was dirty fuel and air filters. So the fuel and air filters were replaced.
On the way back to Orlando the 'problem' happened again. The car ran for about an hour
then black smoke with sluggish acceleration and when the traffic became stop and go the
car stalled. It started again after about a 30 minute wait.
This time I took the car to my local mechanic. His diagnosis was bad fuel. So the fuel
tank was drained and the filter at the bottom of the tank was replaced.
All was well until I drove the car for a continuous hour and, yes, the 'problem' happened
again.

Any and all suggestions as to what is the cause of my 'problem' are greatly appreciated. Thank you.

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  #2  
Old 12-01-2003, 10:03 PM
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I'll throw this out for discussion - is it possible that the ALDA is intermitently sticking in the boost position?

Sixto
95 S420
87 300SDL
83 300SD ... $1100, see cars section
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  #3  
Old 12-02-2003, 01:14 AM
ForcedInduction
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Stuck open injector(s)? Valve(s) not sealing? EGR stuck open?
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  #4  
Old 12-02-2003, 03:47 AM
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my suggestion is that you look into adjusting your valves. I had a similar problem with the acceleration and the smoke, and I went ahead and adjusted my valves, and the car runs like a champ ever since.

Only problem is that you will need the special valve adjustment wrenches, and a feeler gauge(if you cannot find a metric gauge that is okay, I did my valves with a standard gauge)

besides that you could try to run some Diesel Purge through your engine, and that might clean whatever gunk you still have left in your engine after all the filter replacement
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1981 240D/297K/4-spd/OM617 (mine)
1982 240D/241K/4-spd (wife's)
1979 240D/291K/4-spd/OM617 (father-in-law's)
1983 300DT/240K/4-spd (brother-in-law's)
1985 300DT/???K/5-spd Intercooler conversion (brother-in-law's)
1985 280TE/160K/5-spd (father-in-law's)
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  #5  
Old 12-02-2003, 07:42 AM
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Thanks for the replies.
Yes, the trap oxidizer has been removed.
Once the 'problem' starts then the smoke is thick and black. The last time it happened, after I let the car sit for 30 minutes, I turned the front defroster on to draw the heat off the engine and it ran a better (faint smoke and ok acceleration) until I got home. To state the obvious: it seems that when something??? gets warm then it doesn't work correctly and after it cools down then it is ok.
And now, while the car starts, the glow plug light no longer comes on. Bother!

Thank you.
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  #6  
Old 12-02-2003, 08:53 AM
R Leo's Avatar
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Oil Change (long)

The 617.952 in Marlene was doing this for a while. It never died comepletely but there were times when you wondered if it was going to take off from the light. She'd leave an almost opaque cloud of black soot in her wake. Almost like a gasser that would 'foul' the plugs if it idled too long at a stop light. On the highway, there didn't appear to be any decrease in power but there was a slight decrease in economy (usually she runs at 25+mpg and that particular tank I didn't get but 23-24mpg)

I wanted to be methodical about solving this problem so that I would know exactly what casued it so I addressed one thing at a time rather than shotgunning it with several probable fixes at once. Here's the tale:

Generally, rapid-onset problems are related to bad, dirty or contaminated fuel. I looked at the primary filter and didn't see any contamination. I did not change them.

Second the second thing I checked was the was the air filter (easy to do and I had a filter in inventory) which was pretty dirty (about 12,000 miles since changed) so I changed it out. There was no improvement in performance.

The problem (which was intermittent before) was gradually getting worse, with smoke and no power occurring after every extended idle (ie long wait at traffic lights).

I had approximately 3/4 tank of fuel when the symptoms began and was now down to about 1/2 tank. I treated the remaining fuel with Power Service (silver bottle) and continued to drive the car. There was no apparent change in the problem (still no pickup and lots of smoke off idle and no appreciable decrease in performance at highway speed)

I drove the car on a highway trip of about 450 miles, filling the tank (from different stations) two more times. Still no change in problem. After returning, I examined the fuel filter again and did not detect any contamination or blockage in the clear filter.

During this time, my shop was occupied by my son's car and I was unable to perform a regular interval oil change. Consequently, with the road trip I had run that particular lube oil about 50% longer than I usually do. Coincidentially, I had also received an e-mail from a friend that discussed 'black-stacking' on one of a pair of Cat-powered gensets that he is responsible for.

To me, the symptoms sounded remarkably similar: lots of smoke coming off idle and with varying power settings but no change in performance under constant load.

Their fix was to change to a different lube oil. Apparently the oil they were using allowed some carbon build-up in or on the turbo bearings causing exaggerated turbo lag in the transition from no-load to load.

I remembered my tardy oil change and made the connection. So I changed oil and, in less than a day's worth of driving, the problem had gone away entirely.

I'm religious about oil changes now.
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  #7  
Old 12-02-2003, 10:07 AM
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87300SDL,
I would bet you have a Turbo problem. It sounds as if your wastegate is dumping boost. However this doesn't explain why it stalls and will not restart immediately. It may have to do with too much fuel in the combustion chambers. Dave M., "GSXR" is very experienced with the OM 603 engine. He might be able to shed more light on this. My truck, a 94 Chevy 6.5L TD w/ 175K miles, was doing the same thing, but not stalling. It turned out some evil critter chewed a hole in the vacuum line that controls the wastegate. Until I replaced the line, some duct tape worked fine - and a mouse trap took care of the critter.

I do know that you do not need to adjust the valves. I'm not sure that is a possibility on a OM 60X engine.

I would start off with checking out your wastegate system, then the ALDA boost system. Hope this helps.
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  #8  
Old 12-02-2003, 11:08 AM
R Leo's Avatar
Stella!
 
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Quote:
Originally posted by D.Blake
It sounds as if your wastegate is dumping boost....It turned out some evil critter chewed a hole in the vacuum line that controls the wastegate.
I would start off with checking out your wastegate system....
I'm not so sure this is right either. Wouldn't a hole in the pressure line to the wastegate disable the wastegate thus allowing the turbo to create more boost instead of less (dumping) boost?
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  #9  
Old 12-02-2003, 12:03 PM
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EGR valve stuck open is the likely culprit. Could be a broken closing spring in it, too -- my Volvo did this with identical symptoms except it never stalled -- the valve could pop closed at idle.

The other alternitive is a bad IP.

Peter
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  #10  
Old 12-02-2003, 12:27 PM
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Lets see, a spring hold s the wastegate closed - they have been known to break or the shaft to temporary bind. As far as what opens it, I am at this point unsure. I do at times get the two systems mixed up (the truck and the Mercedes). Manifold pressure does operate the ALDA which increases fuel delivery. Overboost is sensed by the wastegate by I have fogotten what mechanism opens it. The symptoms made think of the wastegate problem, not the method of operation. Having said that, the EGR suggestion is a good one. My truck doesn't have one and both of my mercedes have manage to "grow" a block off plate where it attaches to the intake manifold. 87300SDL-Please post the resolution if your ever find one!
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86 300SDL 340K (for sale)
83 300SD 205K (gone)
06 Chevy K3500 LBZ CCLB 50K
94 Chevy K2500 6.5L TD 250K (gone)

Last edited by D.Blake; 12-02-2003 at 12:33 PM.
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  #11  
Old 12-02-2003, 06:31 PM
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The normal EGR "cycle" on a diesel is to be closed at idle, open gradually to full open at partial load, the close again as load increases -- this is due to the nature of the combustion. NOx is highest at medium load due to lean conditions, drops off as load increases due to richer conditions and lower flame temp.

What happens when the EGR sticks open at low speed is about the same things as over-fueling -- there is so little oxygen from the exhaust gas blowing into the combustion chambers that the fuel injected cannot burn properly -- hence the black smoke, funky rattle, and exceedingly poor performance. The Volvo, when this happened, would barely move. More throttle pressure caused the smoke to get blacker, nothing else. I had the turbo rebuilt (it was dead, too) thinking that would cure the problem, but it re-occured during the test drive after I got the turbo back in. What clued me in was that it only happened after the engine warmed up -- it was fine cold!

Plate off the EGR and see what happens.

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!
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  #12  
Old 12-03-2003, 01:24 AM
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i don't know a lot on this subject. but one time i had the hose that goes to the oil seperator blocked, it built a lot of pressure in the engine and it smoked and stalled. maybe u can check this out? also is your oil level going down?
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  #13  
Old 12-03-2003, 09:42 AM
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Stella!
 
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Quote:
Originally posted by D.Blake
Lets see, a spring hold s the wastegate closed - they have been known to break or the shaft to temporary bind. As far as what opens it, I am at this point unsure.
Bleed air pressure from the compressor side of the turbo opens the wastegate against the wastegate spring pressure. A hole or compromise in the wastegate hose allows the pressure to be vented to the atmosphere, effectively preventing the bleed pressure from forcing the wastegage open as designed and consequently resulting in an unintended increase in boost.
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  #14  
Old 12-03-2003, 07:15 PM
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Excessive black smoke won't be produced by a stuck wastegate -- the would give you more power, but fuel delivery will still be properly controlled.

Dirty fuel filters won't give black smoke, either -- no fuel, no smoke.

The only other thing that could have this effect is a stuck injection timer, giving over-advanced timing at low speeds. Not an issue on the Volvo, as the timer is driven by the intergral lift pump on the VE pumps, not a cetrifugal device. Will also make it sound like a Mack truck, too -- lots of combustion noise at idle.

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!
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  #15  
Old 12-05-2003, 10:28 PM
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The mystery to my "problem" has been solved! The culprit is a bad E.G.R. valve. My mechanic disconnected the valve and the "problem" stopped.

Many thanks to everyone for the replies. I appreciate all the help.

--Holly
Orlando, FL

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