DPA pump stuck plungers

[John b]

I read somewhere that connecting an injector test pump to an oulet on a DPA pump, pressurizing it and turning the pump by hand until the corresponding fuel gallery lines up will free stuck plungers. It sounds feasable but has anyone tried it? Curios to know if it works and would possibly save a pump strip

[John b]

Well to answer my own question, yes it does work! Removed the pump which would bleed ok but had no fuel to the injectors after marking its position for timing. Connected one of the outlets to the injector tester and pumped it up to 1000 psi, turned the pump by hand until the corresponding gallery lined up and the plungers popped back down. Works fine now, I will add a can of injector cleaner to the fuel to clean and lube the pump but it has saved having to strip the pump or pay someone else a fortune to do it

[Billy26F5]

Very good trick, probably not valid on an in-line pump unless the delivery valves are removed. Well worth doing on a rotary pump.
Sandy

[John b]

I think you are right about the in line pump and delivery valves Sandy, although an in line pump is far easier to strip apart than a CAV, as long as the settings aren't altered

[shepp]

What happens also with the DPA pumps is that the metering valve sticks in the zero fuel position particularly when the stop control is left pulled out and the engine is not run for a long time. Cranking the engine with the stop control in and at the same time tapping the top of the throttle spindle, the stop spindle and the pump cover with a toffee hammer usually sorts that one out in most instances. I think a stuck pump plunger will be less common than a stuck metering valve.

[Billy26F5]

John and I were discussing this very subject, with the main blame on modern diesel, although leaving the stop control out for any length of time isn't really a great idea either. I suspect our MF will need this treatment when we eventually get to that stage. Good to know another trick for fixing it.
Sandy