Bosch Service Manual 4 6.3 fi pump

Does any have the service manuals 4 the fuel inj pumps on 280se 2.8 ltr & 6.3 ltr.could u e-mail me a copy?

[stevebfl]

What kind of info do you need?

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

[This message has been edited by Webmaster (edited 03-14-2000).]

Hi Steve!
Basically I would like a schematic of the inj pump to give me a better idea of whats inside.I have the merc w/shop manual but this does'nt give too much away.Also the working principal.Is it the same as a diesel pump? Any info would be welcome.
Regards
Peter.

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[stevebfl]

The basic pump design is like a diesel. It is an inline piston pump. Each piston is pushed up (by a cam) and springs down. The fuel comes into the chamber as the piston exposes the feed hole on the way down. The way quantity is controlled is by cutting angular relief along a portion of the piston edge. This is like a pie section removed from the surface. When the piston is rotated into the area of relief a longer effective stroke is accomplished and more fuel is delivered. I have a picture of this in from MB manual.

All 8 pistons are geared to a rack gear so that a forward/backward movement rotates all the pistons together (this is the most important calibration a pump shop does. Once the pistons all work together the governor in the rear housing is in charge of moving the rack.

The rack moves under the influence of a roller rolling on a three demensional cam. The cam has slope in the rotational sense and in the longitudinal sense.

The rotational cam movement comes from the throttle movement. Throttle movement turns the cam.

Longitudinal movement comes from governor style flyweights which cause the cam to move forward and backward due to engine speed. There are three springs opposing this movement with different lengths and spring rates. Each spring has an RPM that it influences most. Each spring has its own seat and here come the adjustments. The spring seat adjustment for idle is accesible by using the thumb-screw adjustment on the back (lower) of the pump. If you saw the back of the governor it would be the center of 5 screws. The other four can only be reached through the back of the pump and adjust the other two spring lands for lower partial load and upper partial load. One of these days I will try adjusting these using our DYNO but otherwise they get left to the pump builder.

In between this mechanism and the rack are multiple linkages that alter mechanical advantage. These are effected by the aneroid (for barametric changes) and thermostat (changes the movement for enriched cold running).

The final attachment to the rack allows the other major adjustment. This is a screw that basically enrichens or leans out the overall decision made by the rest of the mechanism. This adjustment can be done through the back of the pump by someone who has been there. It definitely shouldn't be attempted untill all external factors have been delt with; mainly linkage adjustments, thermostat function (absolutely the number one problem by a huge amount) and all other basic engine set-ups.

If you would like the picture of all this please email my work address steve_ci@bellsouth.net I will scan it and attach it to an email.



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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician