1985 300D very sluggish at low speeds - Page 2 - PeachParts Mercedes-Benz Forum

300SDog · #16 09-24-2007, 08:37 PM

Quote:

Originally Posted by Biodiesel300TD

Valves that are out or adjustment aren't going to make your car accelerate extremely slowly.

Nah, you're chasin ghosts not adjusting valves first. Classic valve symptoms: slooow start and weak performance, no top-end speed either. Did the valves on w116 300SD I bought couple of weeks ago all of em were out of adj, and performance improved across the board.

Brake light shares sensors with fluid reservoir level, Brooke.

#17 09-24-2007, 09:23 PM

Quote:

Originally Posted by DieselDog

Brake light shares sensors with fluid reservoir level, Brooke.

The "brake" light is shared by the reservoir and the parking brake; the "circle symbol" is just for brake pad wear.

Diesel911 · #18 09-25-2007, 11:08 PM

Quote:

Originally Posted by brooke

hey everyone,

I just purchased a 1985 300d and it is incredibly slow to start.

I can push the pedal to the floor and if I'm not parked in total flatness
I go nowhere. The problem seems to get better after the car is warmed up a bit. But when warm I can still put the pedal all the way down and not go very fast at all. The primer pump appears to be leaking and the valves haven't been adjusted (could that help the problem?). I recently changed the fuel filter and prefilter. Once the car is to speed it cruises but before that it's tough to make it up hills.

Sometimes the car doesn't cut off and I have to lift the hood and manually shut it off. It doesn't always happen.

Please help I go dangerously slow.
Thanks

When I firs got my 84 300d 8 months ago it also ran slower than expected (though not as bad as the stated problem). I found that the throttle linkage was adjusted soooo slopey that it would not go all the way to full throttle. I adjusted the linkages from the pedal to the bell crank and followd the Bell crank rod towards those levers where the manual shut off; there is 10mm bolt you can loosen to manke an adjustment. Another though is is that that bell crank that goes to the pedel has rubber if that rubber is rotted out you also will not get full throttle movement.
Other thoughts: Is the fuel supply pump putting out enough pressure? The valves in them get old, the valve springs somet times rust and (I have not looked in mine yet) there used to be a filter screen inside of the pump. Also the plunger spring inside of the supply pump some times breaks and lowers the pumps output.
Next is, there is a spring loaded fuel pressure regulator (for the injection pump housing) on the fuel injection pump some times these stick or the springs brake (rarely) wich would cause a low fuel delivery pressure.
A last but more bazzar thought: I had a BMW motor cycle that I could not get full speed out of it turned out that the clutch plate was saturated with oil; symptoms= high engine speed but low on the road speed. In your case maybe it is not the engine at all but something slipping in the transmission.
Of cours improper injection pump govenor adjustment (high idle speed set to low) or timing could also cause the same symptoms.

winmutt · #19 09-26-2007, 12:26 AM

Dont adjust the ALDA until you have verified everything else is in top shape.

Clean the ALDA banjo bolts
Adjust Valves
Adjust Linkage
Clean/poptest Injectors
Inspect Prechambers

The two hoses on the ALDA are fine. One is for the ARV turbo which is Cali and one year (85) Federal issued.

Adjusting the linkage does wonders.