300Sd barely runs
 

1982 300SD

problem: 150 miles into a trip my girlfriend noticed a strange vibration/noise. When she realized it was the car and not another nearby vehicle she pulled off into a rest stop. The car died on her as she pulled into the parking spot and would not reastart right away. The coolant temp was norm as were the other gauges in the vehicle. When she opened the hood there was smoke that she described as comming from underneath the aircleaner.

I went and picked it up. Started right up on the first try, but makes a terrible knocking sound and idles erraticly. I also noticed black smoke comming from the exhaust and there is almost no power when trying to get her to move.

What I have done:
I parked her and pulled the aircleaner and intake ducting. the turbo shaft turns easily and does not seem to have any ecxessive play. I also pulled the valve cover and everything looks neat and in order. That's all I have done so far. Any ideas????

How dirty is the air filter? When were the fuel filters last changed? Is the turbo spinning when the engine is running?

the airfilter is fairly dirty. I cleaned it about 4 months ago. I always have a lot of oil sitting in the filter tray when i go to clean it. Normal???

I replaced the fuel filters about a year and a half ago, and the car hasnt been driven more than 6k since then.

I will have to check if the turbo spins when the car runs tomorrow.

Can you post a video of the engine running on YouTube and then link it here?

Absolutely. I'll try and post get this all done tomorrow a.m.

The basic place to start is to change the Fuel Filters and make sure you are getting Fuel to the Fuel Injection Pump. (It only takes one load of contaminated Fuel to stop up even a new Filter.)

If you have more than 1/2 Tank of Fuel I believe the swapping of the Fuel Inlet and Outlet Hose positions that can be done on the 123s where the Tubings going back to the Fuel Tank are will also work on your SD.
That bypasses the Fuel Tank Screen and draws Fuel from a higher position in the Fuel Tank (only for testing because you would also run out of Fuel sooner than your Gauge indicates if you leave it connected like that).

This is going to sound crazy...but make sure your vent line on the valve cover isn't plugged up. Positive pressure in the crankcase will act on the shutoff solenoid and reduce or cut off fuel depending on the severity. I went through that years ago on my W116 and it took a LONG time to figure out.

Update
 

Mercedes-Benz 300SD Clacking Sound - YouTube

The turbo shaft is spinning, the fuel filters have been replaced and the vent from the valve cover is not bloacked. This knocking sounds terrible. it starts up fine, but runs really bad. I have some pics from under the valve cover and nothing seems askew with the motor off. I'm afraid I may have bent a rod.

Did the engine run low on oil?

It's a little low now, but it's not anywhere close to a critical level.

Have you tried cracking each injector line one by one?

It's not a rod. The noise is not deep enough. Get a stethoscope and put it on various parts of the engine to isolate the sound to a specific place. Put it on the vacuum pump.

Did she buy fuel somewhere along the way?

Check the valves.

I was wondering if she pumped gas in. Thats if she fuelled. Remove the gas tank lid and smell.