[Vwdiesel] Injection Pump noise ( calling all good men to the front )

[H.Hagar]

One of our comrades has a "NOISY"   like a threshing machine.    Noise
comes and goes , but is not related to RPM:  ( hm eh ? ).

First we could use more info  like type and number of pump and type
and year of engine.

I have two pumps in front of me so I know what's inside. They are completely
disassembled.

Question :     What might make a racket ???.

1.    Cavitation.

2.    A dry bushing at sprocket.

3.    Elastomeric coupling has disintegrated.  ( attacked by fuel additives)

4.    Flyweights are hitting something.

5.    Loose srocket.

I have a lot of trouble getting a handle on this one , because ALL noise
that I can think of ,   will change with RPM.   

Hagar.