My rear windows on my '80 300TD work but they are very jumpy and it seems like the up limit switch doesn't work. I looked at the other posts and they really don't have the same symptoms.

Is it a regulator? The motor works but just not smoothly. The left window works full up and down but the right gets stuck down if I put it more than half way.

Any ideas on a car that runs great until there is less than a 1/4 tank of fuel? Idles real rough and sometimes even stalls!

Rough idle and stalling may be due to out of calibration fuel gauge. Could also be due to algae in the tank and the sender part of the gauge. This often shows up when running the tank to a low level, but it can also be seen as black material in the clear filter.

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150

Cant help you with electric windows..... but its bad habbit to bottom out diesel fuel tanks. Basically you risk pushing sludge through the system and frequent problem with fuel filters. Better idea is to fuel up when tank has 1/3 left.

BTW, one of worst things you can do with diesel engine is run the engine bone-dry out of fuel. Basically the engine will continue to combust while some chambers get no fuel lubrication at all...... toasting the valves, scorching the bores and roasting the rings as diesel engine slowly runs out of fuel.

I'm not running it below 1/4 of a tank because it just idles too rough. The filter is not that dirty or clogged. This is not an easy one to fix either.

Window problem is probably a worn regulator. Get a used one at the junk yard.

Fuel problem is algae in the tank, clogging the tank screen at low levels. Drain tank, remove and clean screen, and get some algecide.

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!

Peter's got good advice..... drain the tank, access top hat shaped screen and clean it. Also douche the tank with algaecide.

Maybe remove the entire fuel tank and have it professionally cleaned and inner coated...... i had this done on Moto Guzzi motorcycle rusty fuel tank with great success.

Full tank of fuel at about 100+ lbs liquid weight logically boosts flow through clogged internal tank screen.....so you probably suffering from diminished fuel draw with less than 5 gallons in the tank.

On the windows, there are two plastic gears in the regulator. The frame of the regulator gets worn, loose, or cracked. The frame needs to hold those gears in there tightly and when it fails the window will start to act like you describe.
Pull off the inside door panel and poke around until you find those gears. They are mounted on the top side of the electric motor. If you run the window up you will see the gears slip and bounce around when the window gets to the top. That is what you hear when the windows are run up to the top.
Window regulator probably needs replacement.

Thanks everyone, I'm on it. I'll let you know how it goes.

I am celebrating a great junkyard find today. Two front seats MB Tex blue with pristine horse hair and foam. From a '78 but who can complain. Its from a 123 and in great shape. Even has the factory german stickers on the springs Good day I tell ya, Good day!

Sounds like you tank filter is clogged. disconnect the rubber hose form the tank to the fuel line and allow the tank to drain. remember a full tank is 17 or so gallons IIRC. Use allen to remove the filter. Or a cheaper method is to measure the allen size and buy a bolt that size, jamb 2 nuts on it and use that to remove the filter. Clean the filter in a wash tank. Additionally check for algae. Use an algicide if you have a problem.
Your window. Check the gears and also while you have the door cover off to check those gears, lubricate the slide section of the window actuator as well as the gears. You can use a moly lube or any grease.
Your windows do not have a lilit switch. the DC motor pushes the window up until you get to the top window trim and then the motor stalls. The lowering limit is a tab in the mechanism set up.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

IF your primer pump is not leaking-

Generally, I run my cars low and occasionally dry before a filter change. Gets all the junk gone.

For you I'd check the primer pump and hoses. Make sure the cigar hose is soft and plyiable. You should have a good fuel flow.
REPLACE THE FUEL FILTERS!@!

Beyond this, I've seen cars which were dogs off-idle performance which ussually was cured by a timing chain and IP timing set.


Michael

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Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E