The DC motor inside the pump would run fine but no gas would be pressurized through the pump.

So I cut the fuel pump apart and did a failure analysis. In case you have not seen the "guts" of a fuel pump, here they are:

The failure was two broken plastic tabs on the end of the DC motor. These tabs drive the Eccentric Plate with 5 rollers that create the fuel pressure.

The tabs are circled in RED. Also notice that the armature is worn about 50% (ie groove in armature).

The carbon brush assembly was also worn about 50% as shown in the RED circles.

If the two plastic tabs had not sheared off, the fuel pump was still usable.

I have no idea what caused the tabs to shear as the DC motor in the pump ran the first time on the test stand. Anyway, a bummer.

Cheers, WWR.

(originally posted on http://forums.vwvortex.com/zerothread?id=2890716)