Date: Mon, 14 Oct 1996 20:23:46 -0400
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: "bob tickle" <ratickle@viconet.com>
Subject: Re: Vanagon Dirvability
John (and others that asked)
Below it the Word Document that Jeff & Jean-Marie Diebolt=20
encoded into their mail text. The info looks good to me.
I can personally vouch for the engine-to-body ground strap
being a problem. Once I replace that and the ignition coil,=20
my 1991 Vanagon is running better than it has in months. =20
Except now I don't know if the broken ground strap caused=20
the coil to go bad or it was just a coincidence.
I will attempt to post the info that was in Jeff & Jean-Marie=20
Diebolt's encoded Excel Spreadsheet. I will try to send it as
attached binary file, since getting a spreadsheet into text=20
form is a pain.
Bob Tickle=09
*******************************************************************
The following information is condensed from a service
communiqu=82. It was intended for dealership personnel and
some of the details must be obtained from other repair
publications. I do not have access to the Digifant I & II
ProTraining manual referred to many times in this document.
Maybe someone with access to that information may be able
to help out. VW must, by law, make all repair information
available to the public. They may charge for this service.
I don't remember the details of this. I quit working at the
dealership before this repair information became available
so I cannot verify its content. Obviously there are more
economic means to make some of the repairs.
Sporadic reports of intermittent misfire or stalling on
Vanagons with Digifant fuel injection. A "Test Sheet" has
been developed to aid in the diagnosis of such drivability
problems. DO NOT ATTEMPT TO "SHORTCUT' THE REPAIR/TEST.
Basic Engine Set-up=20
This information can be found on the microfiche or on pages
35-39 of the Digifant I and Digifant II ProTraining Manual.
There can be no deviation from the basic checks.
PB Campaign Campaign Circular PB:
Assure that the campaign was performed as outlined,
including the relocation of the vent hose and removal of
the restrictor, if applicable. If this campaign is done
wrong you will have a drivability problem.
Carbon Build up=20
It is very important to check for carbon buildup on the
intake valves. To check this you must remove the intake
runners and visually inspect the intake ports. Remove
carbon deposit before continuing. Refer to Technical
Information Circular, Group 24, Number 89-04, dated April
24,1989.
Fuel Quality
Check that the fuel is a quality grade and octane rating,
devoid of water, alcohol, and other impurities. See
TechTalk tape and card #203.
Ignition Cables=20
Check for corrosion and fit. This primarily concerns the
terminal of the coil. In addition if you have Beru spark
plug connectors, replace them. Check the resistance of all
wires. Coil wire value is 2000 Ohms resistance and plug
wire value is 6500 Ohms resistance.
Ignition System
Check to see if the ignition coil is leaking. Use green
labeled coil Part #211 905 115D.
Ground Studs
If the vehicle cuts out around corners it is most likely an
interruption in the circuit for the ground being provided
for the fuel pump by the ECU, check the wiring between the
two components. Move the ECU ground connection to the seat
belt retaining bolt as a check. If this solves the problem
install a new body ground. Protect for corrosion when
installing the new ground. Check the ground connection near
the coil, on the left side of the engine compartment. This
is also the ground for the oxygen sensor and the fuel pump
relay. In some cases the fuel pump relay has been the
problem and using part #443 951 253K has been used with
some success. Refer to the Vanagon Wiring Diagram for
details.
Electric Harness
Check the connectors in the ECU plug and at all the other
fuel system components connections. Are the connectors in
good shape, with a solid crimp on the wires? Are they the
union power timer connectors? Power timer terminal can be
recognized in the following way: These terminals are
basically the same as the original except that a stainless
steel spring is crimped over the original terminals contact
fingers. This keeps tension along the contact surface
during movement, vibration and high current draw. Fuel
injection wire harness internal connections (injector power
and ground terminal #94, G1 and G2) butt type connector
inside the harness cover can also be a problem.
Intermittent missing in lower gears and some at highway
speeds. These three connections are to be soldered. (I have
no other information on the exact location of these butt
connectors other than a photo copy that is to dark to point
out anything and the communiqu=82 states see your District
Service Manager for approximate locations.) Refer to
harness checks in the microfiche or the Digifant I & II
ProTraining manual, pages 40-43.
Oxygen Sensor Wiring
High resistance or a short in the wire for the oxygen
sensor (the green wire that would be disconnected during
C.O. adjustment) that runs inside the fuel injection
harness. Symptoms are missing and cutting out with thick
black smoke coming from the tailpipe. The green wire is
replaceable without replacing the complete harness, part
#443 971 108A.
Temperature Switches
Be sure that the temperature switches are within
specifications. Refer to microfiche or Digifant I & II
ProTraining manual pages 17 & 18.
Throttle Body and Switches
Throttle plate stop screw adjusted properly and check the
throttle switches with a multimeter, refer to microfiche or
Digifant I &II ProTraining manual page 13. Replace if shaft
is worn.
Air Flow Sensor
Air flap binding and potentiometer within specifications,
refer to microfiche or Digifant I & II ProTraining manual
page 18. Added note: Even if the air flow sensor checks
O.K. it may still be a problem. After making a complete
check of the system replace the air flow sensor. Make sure
a ground wire is added between the air flow sensor and the
right cylinder head.
Fuel Injectors
Spray pattern and delivery quantity (too much and too
little can be a problem) and leakage. Refer to microfiche
or Digifant I & II ProTraining manual pages 19-21.
Deceleration fuel Cut-off
Refer to microfiche or Digifant I & II ProTraining manual
page 22.
Carbon Canister
Be sure the evaporative system is working properly, refer
to micro fiche or Digifant I & II ProTraining manual page
34.
Fuel Pump Circuit
Check connections at relays and grounds. Check the P1
connection in the wire distribution box on the firewall. In
the distribution box there is a stud with several power
wires attached. Tow of these wires are for the fuel pump
relay and the ECU relay. Check for corrosion and poor
crimping of connectors.
ECU Versions
After checking the complete system and the problem persists
replace with the latest ECU's. Part #025 906 022D for fuel
control and part #251 907 393D for idle control.
Air flow Sensor Modification
The addition of a capacitor to the air flow sensor wiring
may help with intermitent miss. (The mechanic at the
dealership says this will also cause stalling after being
driven awhile and will not restart for about 30 minutes.
Runs fine when restarted.) A 10=E6F/25 Volt capacitor can be
installed.
1) Remove the connector from the air
flow sensor.
2) Pull back the boot on the connector
for the air flow sensor.
3) Remove connectors 2 and 4 from the
hardshell connector for the air flow
sensor.
4) Cut the connectors of the ends of the
wires, strip the ends of the wire and
connect the "+" side of the capacitor to
the #2 wire and the "-" side of the
capacitor to the #4 wire. Crimp on new
power timer connectors on the #2 and #4
wires and reinsert them back into the
hardshell connector.
5) Reconnect the airflow sensor
connector.
6) Connect a ground from the metal part
of the air box to the empty 6mm ground
connection point on the right cylinder
head.
----------
> From: HelFle8953@aol.com
> To: Multiple recipients of list <vanagon@lenti.med.umn.edu>
> Subject: Re: Vanagon Dirvability
> Date: Sunday, October 13, 1996 8:35 AM
>=20
> I tried using a base 64 decoder with no joy. Can you resend in ASCII
format?
>=20
> Thank-you in advance.
>=20
> John Fleming