[Vwdiesel] Fw: max fuel adjustment --(things are a cooking )

H.Hagar h_hagar at prcn.org
Thu Apr 1 10:35:28 EST 2004

----- Original Message ----- 
From: H.Hagar 
To: vwdiesel at vwfans.com 
Sent: Thursday, April 01, 2004 7:29 AM
Subject: max fuel adjustment --(things are a cooking )

I am delighted to see some of you take an interest in the workings
of   " Da Pump " ----   lets face it changing wheel bearings and 
brakeshoes --- is ok --but ---mastering the pump is like getting your

So the more of us dig in to it --the faster we will tame the little cutie.
--  Taming the Shrew ?    

I just received the new edition of the Bosch Book on our injection pumps from Bentley   -- W.A.Thomson wrote. --- -- if it is Bosch Diesel Engine Management
it is a great book.   I am looking for the old one too.

I see a lot of you are beginning to understand that many different adjustments
interact.  ---- Hence the beauty of the performance tuned Rabbit.

A  " BOOK"  tuned 1980 Rabbit will loose to a Performance tuned (Hillbilly)
every time.

Like Gary Orlando  mentioned the factory settings for many reasons , makes for
a slow Rabbit.

Only one thing controls the amount of fuel injected each stroke --- the position
of the control sleeve ---there are no needle valves or the like.

We have but one piston , and the stroke is fixed  at about 85 thou (inch).
So to inject less fuel we have to spill the excess fuel back in to main body of pump.
This is done by a holow center in the piston A small hole is covered by the sleeve.
So for minimum fuel hole is not covered----for maximum the hole is covered.

So who or what pushes the controlsleeve back and forth ???    stay tuned 
it is getting interesting.


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