[Vwdiesel] Injection pump testing for beginners 2----( OLD Rabbits mostly...

[LBaird119 at aol.com]

The simplest of all tests ?  ---at idle pull the cold start ----if you get a 
big difference
in sound and or smoke ?  your pump is worn.

  Seening that very few of these pumps fail, the first thing I'd check 
(if the smoke changed) would be compression and injectors.  If they
have ~130K miles or more on them, replacement will likely make a 
variety of improvements.
  I've always used the sound change in pulling the advance lever as a 
quickie indicator of if the timing is set properly.  Cold:  If there is no 
change, the timing is usually too retarded.  If there's little change but 
it's really rattly then too advanced I'd guess. Never have encountered 
that scenario.  A nice, noticeable change and a bit smoother running 
and the timing is usually just right or real close.  Hot engine:  No change, 
timing is slightly retarded.  Very slight change in the sound is just 
right.  Never have seen it make a change in smoke but the most probable 
causes of white smoke is a bad injector or low compression (glow plug/s 
if just the first couple minutes.  Black smoke would likely be a bad 
injector.
     Loren