Document: PD Motor Stalling When Accelerating, Tandem Pump (Solution)

All pump-nozzle engines, experiencing vibrations when accelerating.

Cause:
Insufficient fuel supply pressure. Pressure limiting valve in the auxiliary pump is not closing.

Solution:
If the target value is not reached, ensure that the filter unit and check valve are unobstructed. Second pressure supply without the filter unit and check valve. If the target value is still too low, replace the tandem pump. Otherwise, the cause lies in the fuel supply.

Test Tandempumpe bei TDIs mittels folgender Prüfung:

Quote:

Measure the pump outlet pressure using a pressure gauge (VAG tool), for this, unscrew the clamping screw of the measuring connection (when viewing the pump from the front, on the left side and below, above the return connection). Pressure requirement, e.g., for the ASZ at 1500 rpm: at least 3.5 bar. If the target value is not achieved, clamp the return line before the diesel filter. If the target pressure is then achieved, clamp the O-rings of the PDE between the inlet and return (= the 2. (Ring from above) - at least partially defective -> replace. Will the delivery pressure also be achieved with a reduced return flow -> Replace the pump.

Author: Michael II