On my 1975 auto 240D W115 , the car starts right up hot or cold. Here is my problem. After driving and warmed up I put in netural or park and the idle will increase and have grayish smoke coming out of the tail pipe, I put in gear and the smoke goes away. I can't get the idle down after it warms up. I adjusted the valves and no change as far as the smoke goes. Checked all of the rods and adjusted according to the specs. I sure could use some help from you diesel pros

Thanks

Doesn't this car have the manual idle speed control on the dash? The knob just to the left of the key is what you are supposed to turn once the engine has warmed up to adjust the idle down. Does it work?

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Are you sucking oil into the intake via a broken diaphragm on the vacuum pump?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

My IP has a seperate oil resevoir built in the unit oil not from the engine.
I thought about the vacuum on the IP would increase the idle when warm.
It's getting too much fuel when the engine is hot.I checked the timing chain when I was in there adjusting the valves and it looked good,all sprockets ends were not sharp and chain looked ok also.As far as the idle cable it set to the specs.

He is suggesting that engine oil is entering the air intake and being burned by the engine, nothing to do with the IP.

How can you tell if this be the case? I rechecked the timing chain and I am going to replace it along with the valve seals and probably rebuild the vac pump. When I first got the car I did notice oil usage just driving around here. The car been sitting for three years. You guys are probably right.
Thanks

that sounds about right, your vaccume pump probibally needs repaired.

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Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac?

As long as they would add one additional commandment for you to keep thy religion to thyself.
George Carlin (Wonder where he is now..)

1981 240d (engine donor 1983 240d) recently rebuilt engine hurray! - No more.. fought a tree and the tree won.

pearl black 1983 240d 4speed (Converted!@$$%) atleast the tranny was rebuilt.

The check valve on the intake manifold was in backwards. I ordered the vac pump rebuild kit and was checking out the manual and wah! la! I wonder who was the mech on this one.