Suddenly I have significantly more black exhaust smoke and a decrease in low end power. The power picks up when the turbo winds up. ( >2500 RPM) But she then blows a big cloud of black smoke that continues until the turbo boost goes down Seems to blow minimal smoke while crusing, but mashing the pedel to the floor will show visible black smoke in the rear view mirror. The car blows a lot more black smoke out the exhaust than a week ago. Checked and changed the air filter. Primary filter looks clear. Checked the boost line from the intake manifold to the ALDA and all looks good. It shows 8 PSI max boost on my boost guage and the ALDA pressure switch on the fire wall is working Ok. I know I have an intermittant very slow vacuum leak somewhere but it's so slow that the door locks will still open after sitting over nite. Could this all be bad fuel? I did buy fuel at a place that I have never been to before. It's a small independant gas station group here in Richmond. It seemed to start a day or so after the fill up. Tried some Diesel fuel injector cleaner, but that was no help. When I checked and changed the air filter I looked to see if there was any excess oil in the bottom of the air cleaner . All looks normal there. EGR valve has been dissocnnected since before I got the car...Had the strainer assembly in the fuel tank cleaned about 6 months ago and all the fuel filters were changed at the same time. It's only been about 8K since that was done... Any suggestions where to go from here. Only other think that has been done in the last 2 weeks was an oil change and the level is right on the mark. thanks Russ

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1978 300 D 258,000 + miles sold 1995
1983 300 D Turbo 152,000 miles
Thank God for the man who put the white lines on the highway

Is it using oil? I'm sitting here wondering if it could be a turbo seal?

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Jim

Jim, No it doesn't appear to be using any oil. It would have to be a big leak to show up in a weeks worth of driving. Also valves were adjusted about 4 K miles ago and the timing chain was checked for stretch. The mechanic said the stretch was negligible. Hoping that things will improve when I fill up again. This will help sort out the fuel issue

Russ

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1978 300 D 258,000 + miles sold 1995
1983 300 D Turbo 152,000 miles
Thank God for the man who put the white lines on the highway

It's not oil...wrong color. Maybe this is a draggy turbo or a stuck ALDA?

It could also be one really leaky injector too. This is what I'm thinking is the problem.

IMHO, 8 psi boost sounds a little on the light side. At full chat, a 617.952 should be making a shade over 10 psi but that doesn't seem like it should make enough difference to create clouds of black fuel smoke

Questions...
How's the idle and starting?

Any noise, nailing, clatter?

On a long incline with the engine speed stabilized above 3000rpm, is there a constant black smoke trail?

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Never a dull moment at Berry Hill Farm.

Start up is quick and crisp as it always has been. Don't hear any nailing or other funny noises Crusing along at 65 mph very little smoke, but step on the pedal and as it accelerates the smoke appears. Not a smoke screen type of cloud but a steady black/ gray exhaust noticable more that it used to have a week ago. Ease off the pedal and the exghaust plume almost dissappears.. BTW it a 123.133.xxx.xxx 83 with 129 K. I'am thinking it's a stuck or real dirty injector. Russ

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1978 300 D 258,000 + miles sold 1995
1983 300 D Turbo 152,000 miles
Thank God for the man who put the white lines on the highway

Draggy turbo, or stuck open waste gate IMHO. I honestly think that a bad injector would show up at start and idle.

At or around 2200rpm does the movement of the boost gauge pretty much match the movement of the throttle? In my experience with my two 617.952s there isn't much if any lag between the throttle and boost once everything is up and spinning.

But, you should hear what gsxr, sixto and PEH have to say first.

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Never a dull moment at Berry Hill Farm.

I like to eliminate the cheap and easy things first - in your case that would be the fuel. If you drive a lot then the next tank would tell you the story fairly soon. If you don't and want to know faster than waiting for a fresh fillup, then I would suggest a bottle of Power Service. Either the whole 16-oz bottle or at least 8-oz of it.

Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles