I have a 78 300D that gives off lots of smoke when accelerating. What are the most likely causes?

What color is the smoke? And is it only when accelerating, or does it smoke while idling and decelerating?

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Ben

The MBs:
1976 300D (W115) - 330K and still going (sort of)
1991 300D 2.5 Turbo - Sold at 221K
1983 280SEL - Sold at 206K
1981 300SD - Sold at 232K

the smoke is dark greyish I believe, most severe upon acceleration

Greetings Gerryh,

The smoke on a diesel is either generally black or what you may see as grey or blue and sometimes a mixture of the two. If you believe it to be more black than blue I'd check the following two things first. The valve to rocker gap, easy to do and then I'd check your start of fuel delivery on cyl. 1 Just from personal experience my start of fuel delivery was advanced enough to cause unburned fuel to spew from the tail pipe leaving a black trail and also killing MPG. Retiming the start of delivery has me back on a no trail tail pipe soot problem and another 4 MPG to the better. Please search this site for start of fuel delivery and you'll come across my post as well as others that describe how it's done if this is new to you. If you decide the smoke was probably more blue than black, please check your valve gaps first to see if they are within specs. In most cases of small amounts of oil burning, it's either an improperly gapped valve or valve seal gone bad, and worse case senerial, worn piston rings. Try the easiest first and you'll be surprised at the outcome. It worked for me when everyone said it was a dead engine, and that just wasn't the case, but definitely not well maintained, engine wise.

Charles