This question is not Benz related specifically, but I know a lot of you guys are Diesel fans in general so I hope you can help.

Is there a quick and dirty way to adjust the boost compensation aneroid on a Bosch VE pump? I can adjust my boost pressure without a problem, but I would like to know a way to change the fuel delivery too. I have taken the cover off of the aneroid only to find a rubber diaphragm attached to a spring loaded rod which seems to go into the pump. Boost pressure would seem to act on this and push the rod downward--allowing the throttling mechanism to travel more.

There is a small screw and locknut on top of the cover but it seems to have no purpose except to limit how far the rod travels upward--like a minimum setting.

Just from the looks of it, it would seem to me that I would need to source a new rod and spring assembly but I'm not sure. Anyone have direct experience with these pumps?

-Joe

Joe:

Maximum fuel delivery isn't set by the anaeriod. There is a wired and sealed screw somewhere on the top half of the pump that sets max fuel if you want to turn it up.

If you don't get some smoke at full throttle, check that you are getting boost signal to the anaeriod -- if you are, then it isn't working properly and needs to be taken apart and fixed.

I'm not sure it is adjustable except by changing the internal springs, though. I don't have a sectional diagram anymore (didn't buy that book I saw .......) but the screw on top MAY work just like the MB, but not if there isn't a spring under it so that the setting on the screw balances the pressure against another internal spring.

If you do get smoke, more fuel won't give you more horsepower, only some more torque, and more smoke!

Incidentally, deliberately overfueling a diesel engine is a criminal act.......

Peter

__________________
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!

Psfred:

"Incidentally, deliberately overfueling a diesel engine is a criminal act....... "

How is that? Too much pollution?

Increased particulates, increased unburned hydrocarbons, in this case all carcinogens, more CO, less NOX. Injecting past BDC can also burn exhaust valves.

And it wastes fuel -- black smoke is unburned fuel, greasy black smoke is WET unburned fuel. If the fuel can't burn from lack of air, why put it in there? Horsepower and torque actually decrease as the smoke gets blacker.

Peter

__________________
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!