'85 300 SD from california. Beautiful car, well taken care of, 280,000 miles. Starts easily. Fixed some intake/exhaust leaks and still has no power. Can't really hear turbo whine. Curiously, no diesel smoke from exhaust when accleertating hard. The turbo spins and is good. Fuel problems????? Help!!!!

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'85 300SD (formerly california emissions)
'08 Chevy Tahoe
'93 Ducati 900 SS
'79 Kawasaki KZ 650
'86 Kawasaki KX 250
'88 Kawasaki KDX200
'71 Hodaka Ace 100
'72 Triumph T100R

If you say the turbo is good, I would think that the boost signal is getting lost somewhere. The '85 model year had a different turbo setup than previous years. I hope someone with an '85 california model will chime in.

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2001 Dodge Ram 2500 Cummins Turbo Diesel - 4x4, auto, 3.54 gears, long bed
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'92 300D 2.5 Turbodiesel - sold
'83 300D Turbodiesel - 4 speed manual/2.88 diff - sold
'87 300D Turbodiesel - sold
'82 300D Turbodiesel - sold

Can I assume that you're on top of the fuel filter changes? I have a 1983 300D-T that once all but completely died because of clogged fuel filters probably from a bad batch of diesel. Just a thought......

Good luck

Alex

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1983 300D (parked for four years)
2012 VW Sportwagen TDI Manual
2001 Miata SE
1962 Chevrolet Corvair Rampside

vwbuge:

Two (maybe three) possbilities:

Inadequate fuel -- change both filters (the big spin-on one and the little clear plastic one in the fuel line. Check to make sure the fuel lines are all good -- the black ones are standard fuel line. Cracks on the suction side can result in air in the fuel -- ususally causes hard starts, though

Did you check for actual boost pressure? I had a bad turbo in my Volvo TD -- absolutely dead until it finally blasted to life when I floored it long enough. Had to have it bored and sleeved.... I turned under finger pressure, but was VERY rough and and "tight spots" in the rotation. I don't know if you can reach the turbo on an MB (haven't looked that hard on my 300D). If you can, WHILE IT IS OFF, PLEASE, spin the compressor wheel by hand. It may float end-to end a bit, but no sideways motion, must spin freely, with no sticking. any roughness in rotation or movement means bad turbo. Also, oil in the intake (unless it is blowby) means bad bearings.

Check for a hose between the turbo and the injection pump -- I know volvo has one, but I don't know about MB -- I assume there is one. Can be from the mainfold to IP, too. If there is one, it must be properly connected on both ends without leaks. If it is off and you make huge clouds of smoke after you hook it back up, you probably have low compression, etc (which would be why it is off -- the on in the Volvo was, too, to hide the bad injection pump).

And change the oil to something good -- low turbo speed could be a result of "motor honey" added to mask excess blowby and high viscosity oil -- I suspect the 300D I just bought has that nice combination as I cannot hear the turbo in it, either (but I know it works -- about makes the car fly when it comes on.....)

Good luck!

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!

maybe I'll try the fuel filters today. I did replace the little device that senses the manifold pressure and advances the fuel pump. As for the oil, I use mediocre stuff. Nothing too expensive but I change it every 3000 miles religously. I was also thinking of replacing the spring on the wastegate. Does anyone think the fuel pump timing can be off??? The turbo does spin freely by hand and at idle if you look in the intake you can see it spinning. KEEP THE SUGGESTIONS COMING !!!!!!!

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'85 300SD (formerly california emissions)
'08 Chevy Tahoe
'93 Ducati 900 SS
'79 Kawasaki KZ 650
'86 Kawasaki KX 250
'88 Kawasaki KDX200
'71 Hodaka Ace 100
'72 Triumph T100R

vwbuge

Please don't cheat on oil quality -- make sure that whatever you use is diesel rated (CD or better) -- if there is no diesel rating on the bottle, it isn't suitable to use in a diesel. This means most over-the-counter stuff at PepBoys, AutoZone, etc. The only oil I see at those type places that is appropriate is Mobil 1 or Valvoline synthetic! Diesel engines all have oil coolers, and the oil runs MUCH cooler as a result. It also has to stay in the bearings under much higher pressure longer than in gas motors (although at lower peak pressure), and standard gasoline engine oil will cause the engine to wear faster.

If you replaced the pressure sensor on the injection pump, it sounds as if it might be out of adjustment -- it controls the fuel delivery volume, not the timing. If it is set too lean, you will be down on power. Too rich would give lots of smoke.

Timing is probably fine -- if it is fast, you get noise and smoke at idle, good power at speed. If it is slow, you get nice quite low speed operation, low power, and smoke at high speed, and loss of power. It will not change unless the chain has stretched a lot since the last time it was set, or someone moved it.

And check for leaks in the plumbing between the turbo and the mainfold -- usually a leak will give you a scream from the turbo, but if it is quiet anyway, loss of pressure in the manifold is the same as no turbo -- no smoke, but no power.

You may also have algae in your tank -- if you get water in there from some reason, and it stays warm (like California is!) algae can grow and clog the filters. There is a "sock" filter (metal mesh screen) in the tank that can get completely covered, resulting in low fuel delivery, and resulting low power and no smoke.

Change the filters and re-prime with the hand pump. You will be able to tell if you aren't getting good flow from the tank cause the hand pump will stay down and only come back up slowly. If so, you will need to have the tank screen cleaned and/or the tank cleaned. Some Redline or other diesel additive will kill the algae. Check at a truck stop!

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!

I FOUND IT!!!! There is a small metal sleeve (1/2 inch around) with a black plastic plug inside, atop the injection pump. If you tear this sleeve and plug off you will find a set screw and locknut. This is apparently an adjustment for the internal linkage. I backed out the setscrew (counterclockwise) one full turn. VOILA!! Power again!!! I was told that if you go too far the linkage will seperate and your car will not accelerate, just sit and idle. Thanks for all your suggestions!!!!

P.S. anyone have any aluminum wheels to fit this car???

Paul

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'85 300SD (formerly california emissions)
'08 Chevy Tahoe
'93 Ducati 900 SS
'79 Kawasaki KZ 650
'86 Kawasaki KX 250
'88 Kawasaki KDX200
'71 Hodaka Ace 100
'72 Triumph T100R