Mav:

You won't damage the ALDA by adjusting it, although the one on the 603 usually doesn't need it.

Don't clean with brake parts cleaner or carb cleaner, etc -- I don't know what the diaghram is made of and suspect it wouldn't be a very good idea to ruin in.

Also, I would check that the pressure lines from the manifold to ALDA were in good condition, and there are not plugs in the lines before adjusting.

Remember, this car has a trap catalyst, and does NOT show smoke like a diesel without one -- by the time you see significant smoke, you will be seriously overfueling. Mine produces just barely visible smoke at full throttle, usually only noticable at night in the headligts of the car behind me. If you have traces of soot on the rear of the car after highway driving, your ALDA is set just right.

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!