smoke under heavy acceleration

[bigbillyboy]

I have a 1985 300td. It starts easy even cold, uses about 1qt of oil per 3,000 miles, so I think that the motor is in pretty good shape. I have noticed, however, that when I accelerate hard, there is very little smoke until about 4,000 rpm and then it starts to smoke black smoke pretty well. It looks like I'm james bond putting down a smoke screen. This is the only time It smokes. I'm thinking it's getting too much fuel, but it may be running out of boost at that RPM and over fueling? it's putting out about 9psi of boost.

Any thoughts. I got flipped off yesterday because of the cloud and want to know if I minimize it.

thanks
jason

[riethoven]

Your ALDA may be adjusted too rich. I have been playing with mine and now I have good acceleration off the line and even when I kick down it doesn't smoke. Try going in a 1/4 turn at a time and drive it for a few miles. When it doesn't have enough power off the line and seems anemic under boost, then you have gone too far.

[rrgrassi]

Mine does that too. I can only see the fogging of headlights at night. Watch a big rig accelerate, and there is usually lots of black smoke. Same with the Ford, GM and Dodge trucks when they accelerate hard.

I think it's a normal part of owning a diesel, but I could be wrong. I noticed more smoke after replacing the turbo switch over valve and adjusting the IP rack dampener bolt. I figure, if they do not like the smoke, then quit tailgating.

My ALDA has not been touched. It still has the plastic cap on it.

[barry123400]

You might want to check the injection pump timing. I beleive for your year there is a sensor to do it with. Could almost be normal as is. But if injection pump is off a little it could increase the amount of smoke. You could turn down the amount of fuel as well . If done and you lost power because you were covering up a bad timing situation it would not make you happy. You have checked your air cleaner element? This symptom is also very charactaristic of a real dirty or obstructed one.

[TX76513]

BLACK SMOKE - Restricted air flow ( dirty / obstructed air filter; plugged exhaust; restrictions in exhaust system; defective turbo / supercharger); Overload; Improper injection (poor atomization, injector dribble, late injection);EGR valve, worn injectors.

BLUE SMOKE - Worn or stuck piston rings; worn valve guides and stems; high crankcase pressure; worn / supercharger oil seals.

WHITE SMOKE - Misfiring cylinders; water in fuel; air in fuel; water in cylinders (blown head gasket, cracked head or liner); lack of compression

[richard u]

I have a 99 e-300 .. It has always left a faint cloud of white smoke...even shortly after break in... if I stomp all the way down on the fuel peddle from a dead stop. 3/4 down no smoke. I seldom need to floor it so it is not a problem.

[bigbillyboy]

I think I'll start out with the simple things first. Tonight I'l change the air filter, then when I get time adjust the IP timing, and valves. I guess it's probably been long enough since I did that last.

I know that there is always some faint smoke on these old 300's, but what's got me stumped is that it doesn't do it under hard acceleration, but at 4000 rpm like clockwork. I have started to accelerate harder more often just to see when it happens. Every time I've got it floored, there is no noticable smoke, but then when I get to 4000 rpm, it's like throwing a switch and out comes the big cloud of smoke. perhaps my filter air filter is restricing flow at that rate and it's just wasting fuel.

Thanks, I'l keep you updated.
jason

[Hit Man X]

Originally Posted by bigbillyboy

Any thoughts. I got flipped off yesterday because of the cloud and want to know if I minimize it.

It's an IDI diesel, what do you expect? My SD and SDL really start to lay the smoke out on full throttle runs into 4th gear around 3800rpm+.

Hell, my SDLs turbocharger leaks like crazy so after sittin a bit it loads up well. I had to sit in the drive thru at the local junkfood place and I brake-torqued it up and then went WOT and blew a BIG, smelly cloud into the open window. Prick I know.

[Samuel M. Ross]

When we were first worked on the 1980 300D earlier this year we had a similar problem in that it would smoke badly when we put the "hammer" down "pedal to the metal". The engine also suffered from a lack of power.

This turned out to be an early California diesel EGR replacement engine and disconnecting and plugging the vacuum to the EGR solved both problems.

I have purchased one of the blanking-off kits through Brian Carlton which I will install soon.

Sam

[bigbillyboy]

the primary fuel filter. I systematically went down the list:
air filter....no change
secondary fuel filter....no change
oil and filter....no change.
double check all boost lines and vacuum lines....no change
pull off primary fuel filter...plugged solid. It looked clean and that is why I (master cheapo) had not changed it with the regular fuel filter service. Since I have replaced it, however, the smoke has returned to an almost indetectable amount.

I guess I need to make certain I add that to my standard service. I'll go broke servicing this thing $20.00 air filter, $10.00 oil filter, $9.00 fuel filter, $3.00 fuel filter, $35.00 in oil. $77.00 and the labor was free!

[Samuel M. Ross]

Originally Posted by bigbillyboy

the primary fuel filter. I systematically went down the list: ... pull off primary fuel filter...plugged solid. It looked clean and that is why I (master cheapo) had not changed it with the regular fuel filter service. Since I have replaced it, however, the smoke has returned to an almost indetectable amount.

Considering the small secondary fuel filter does much of the filtering, it seems unusual for the secondary to become like you say "... plugged solid" . You must have really forgotton about it for quite some time.

I'm putting my primary fuel filters on an every other oil-change replacement schedule... and with this I will be really shocked if it becomes "... plugged solid" !

Sam

[Brian Carlton]

Originally Posted by Samuel M. Ross

Considering the small secondary fuel filter does much of the filtering, it seems unusual for the secondary to become like you say "... plugged solid" . You must have really forgotton about it for quite some time.

I'm putting my primary fuel filters on an every other oil-change replacement schedule... and with this I will be really shocked if it becomes "... plugged solid" !

Sam

One of you fellows is confused on the terminology.

The primary fuel filter is the first filter on the way to the fuel pump. It's a clear plastic device that does the coarse filtering.

The secondary fuel filter is the final filter between the fuel pump and the IP. It's a round canister that does all of the fine filtering.

I don't believe that the primary filter was the culprit for the smoke condition, and I've got a difficult time understanding how a plugged secondary filter can cause excess black smoke at 4000 rpm at maximum power........

[Samuel M. Ross]

Originally Posted by Brian Carlton

One of you fellows is confused on the terminology.
The primary fuel filter is the first filter on the way to the fuel pump. It's a clear plastic device that does the coarse filtering.
The secondary fuel filter is the final filter between the fuel pump and the IP. It's a round canister that does all of the fine filtering.

bigbillyboy - Sorry for any confusion I might have caused by my termonology faux pas regarding the names of the two fuel filters.

You are right Brian... the term "Primary Fuel Filter" apparently is the same as "Pre-Filter", and the main "spin-on" filter is technically the secondary fuel filter. My mistake but one I now understand was easily made considering how illogical it is to call the main/high capacity filter in any filtration system... to call it the "secondary filter". I guess one could say that it's logical to call the first component in a system the "primary" and the 2nd the "secondary".

I think I'll just start using the terms "Pre-Filter" or "In-Line Filter" [that is not always "clear" by the way] AND call what I think of as the main filter, I will now call the "Spin-On Filter". This way I'm less likely to contribute to the all-too-frequent confusion as to what we call various components on our beloved MBZs.

Brian - You seem to be right behind me a lot as of late!? You wouldn't be purposfully following my POSTs on the FORUM in order to be there to quickly point out any technical gaffe or faux pas I might commit? You wouldn't do that would ya?

Sam

[TheDon]

mine doesnt smoke at all.. im dissapointed..

It's called primary because it's the first filter in the stream and it captures all the large particles before it reaches the main filter.