[Vwdiesel] Injection pump for beginners ---( the LDA -thingy )

[LBaird119 at aol.com]

> Fueling srew located ?   There are two,  one on the pump , and one on LDA.
> Both affect the full load stop. The screw on top of LDA sets the trigger 
> point (PSI)
> where more fuel is injected. 

  The one on top actually sets the full load stop start so to speak.  It sets 

the lower "limit" or starting point of additional fueling once the LDA starts 

in.  Yes it sets the stop but it and the other screw work together to set 
upper limits at the same time that the one in the lid is setting your range 
of additional fuel.  Think of it like the mountain climber game on price is 
right.  The range of the little guy is the additional that the LDA puts in.  
Adjusting the screw on the end of the pump raises and lowers whoe much 
fueling he covers.  The screw on the top sets the bottom of the range he 
covers, making it larger or smaller but not moving the range.
(I think I got that right)

Inside LDA is a big adjusting nut for setting volume per
> 
> stroke. BOSCH calls it a CONE adjustment ( bad translation IMHO) it is a rod
> with a taper on it and a follower pin mounted 90 degrees to the rod moves 
> the full load stop
> inside pump.  So yes we have one more seal to deal with.


  No, the closest thing to a big nut in there is the spring perch height 
adjustment.  It's a notched ring, just enough for dentet clicks.  That 
sets the tension on the counter pressure spring and would raise or 
lower the pressure at which the LDA starts adding extra fuel.
  The cone adjustment really is a cone shape.  It's ground off center  
of the rod it's on, which is attached to the diaphragm.  Rotating that 
raises or lowers the fueling range the little mountain climber guy is 
covers.  The range remains the same size.

> 
> If given a choice always buy the pump with the LDA on it --even if you do 
> not need
> it at this time.
> 

  I see no reason for that.  Sure you could "play" with it a little but the 
TD pumps cost more and if you don't have a turbo there's no real 
benefit from having one other than bragging rights.  There's also the 
thing of people that need one and can't find one because someone 
else stuck one where it wasn't needed.  They are more limited in 
supply than an NA pump, which will cover NA applications just as 
well with no "extras" you don't need and can't use.
     Loren