Date:         Mon, 09 May 94 22:28:38 EDT
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         derekdrew@aol.com
Subject:      New Fuel Inject Test Data

Many of us have heard by now about the wiring harness fix for the 
hesitation/surging effect that many 86-91 Vanagons have. I have 
installed this fix in my own van and have suggested other owners 
of these vans think about getting the wiring harness fix too.

I noticed that the addition of this harness alters the normal test 
results that one would get when taking resistance readings 
when trying to diagnose problems with the fuel injection system. 
Accordingly, I got out my "Vanagon/Type II Fuel Systems Pro 
Training Manual" that is published by VW for its own dealer 
mechanics and decided to pencil in what the new resistance 
readings should be.

I turned to page 107 of this manual and I see reference to 
readings that one would get between terminals #3 and 4, 
between 2 and 4, and betweeen 1 and 4. But then I looked at 
the factory advisory Joel gave us and it doesn't really refer to 
these readings. Instead it says:

****************************************************************
NOTE
When troubleshooting this system and performing continuity checks, the
following should be noted.  Due to active components in the wire
harness, Part No. 025 906 302, there is not continuity between pin two
of the connectors.  The following chart on page 2 lists the resistence
of each circuit.
  ---------------------------------------------
  Terminal      Approximate
  Number        Resistance
  ---------------------------------------------
    1           Zero Ohms
    2           Greater than 1 Meg. Ohms
    3           Zero Ohms
    4           Zero Ohms
    5           Zero Ohms

****************************************************************************

I cannot determine from the above what these new readings 
refer to. They refer to resistance readings from certain 
terminal numbers but I don't know if these terminal numbers 
are on the harness, on the old harness, on the air flow box, 
or over near the ECU. Furthermore, they refer to readings 
would get from a terminal number 5, but I see no reference 
to terminal number 5 readings on page 107 of the manual, 
which is the page devoted to the air flow sensor.

Are these resistance readings between each terminal number and 
pin #2? ...between these terminal numbers and ground?

Any person on the internet mailing list who feels he knows--or
who can figure out--what VW means by the above advisory is 
urged to clarify this for us Digifant owners. Perhaps I am simply
looking at the wrong page of the manual. 

If you do not own the factory training manual I mentioned, 
and you have a Digifant system (86-91), send me private 
e-mail with your snail-mailing address to borrow a copy 
from me.

For that matter, the manual also covers *all* fuel injected busses, 
so you should have a copy if you have any Vanagon, or fuel 
injected bus too.

Lets get to this problem and resolve it. How do we know how to 
adjust the test result figures we should be obtaining if we can't 
make sense of the terminal resistance readings VW tells us to use.