1987 300 TD
As you may remember, several list members have made various suggestions of
things to check. The problem appears to be internal to the Inj
pump. There is good fuel flow through the filters. (no algae) Filters
were replaced anyway. just to be certain we eliminated many sources of
possible problems, I put an electric fuel pump ahead of the transfer pump,
took off the oil filler cap to eliminate the possibility of crankcase
pressure buildup, removed the IP side cover and manually held the rack to
the full delivery position with the vacuum disconnected to the shut
off. In this test, we got continuous flow through the pump and out the
return line, but not enough fuel to start and run to the injector nozzles
(tested by cracking the lines and comparing to the SDL engine) I tested
the shut-off valve with a mighty vac and it appears to be working
correctly. The rack pulls to the no-fuel position with the vacuum applied,
and returns to a partial delivery position with the vacuum released.
Next weekend I am going to try replacing the copper seals and o-rings on
the delivery valves, but I am running out of ideas. I believe holding the
rack to full open will eliminate any influence of the mechanical governor.
Each element of the pump operates off its own lobe of the cam, so it is
unlikely that the cam had a massive failure. since fuel is flowing out of
the IP overflow at the filter, I believe there can't be air pockets in the
pump.
Does anyone else have any ideas? If a copper seal is bad, would that
affect all the elements, or just one?
Loren (frustrated, cause I think this is something simple)
