My 300 SD suddenly lost power intermittently. It acts exactly like the turbo is not working. I'm guessing its somehow related to the turbo control.

This is what I do know:

Brand new Bosch Fuel Filters (replaced after trouble started)
The turbo spins free
No carbonpluging the prossure switch
no apparent vacumme leaks - Vacumme pump working

ANY IDEAS what to check????

Thanks!


UPDATE- bypassing the Switchover valve (vacumme valve between the manifold and the aneroid compensator on the injector pump) by attachingboth vac lines togethergives full power.
The switchover valve "seems" to function when bench-tested.
I don't have any electrical diagrams for the function of the switchover valve or pressure switch circuit.
ANY help would be great!


SOLVED- The pressure switch in the manifold is bad. Switch is stuck closed.