This is long, but for the record and the archives, so please bear with me.

John Rodgers
88 GL Driver

In my Digifant FI manual -

Part I

Vanagon/Type II Fuel Systems - Digifant

TROUBLESHOOTING GUIDELINES

Poor Idle:
a) At operating temperature
1) Throttle Switch
2) Idle stabilizer system
3) Evaporative Emissions System

*2) page 115

*NOTE !!*
This procedure is for vehicles with manual transmissions only! Vehicles
with automatic transmissions require that the  rear wheels be off the
ground, rear brakes locked, and the transmission in "Drive". Two people
are required to do all checks. Please refer to the FI manual itself for
additional instructions.

Idle Stabilization  - Checking the basic system

___ Engine at operating temperature, oil temperature at least 80C/176F.

___ Throttle Switch connected and functioning properly.

___ All electrical consumers must be off  during checking procedure.
Coolant fan should not be running when observing readings.

___ Connect multi-meter US 1119 (or equivalent) to the idle
stabilization valve using test adapter VW 1315A/2. Set range of the
meter to 2 amp scale (readings will be in milliamperes)

___ Run engine at idle and observe reading. Basic idle value should be
430 +/- 15 mA. If no: the go to Idle Speed/CO Content - Checking and
Adjusting.

___ If you have a fixed ( non-fluctuating milliamp reading and the idle
is  high - approximately 1100-1200 RPM) , check for signal from terminal
1 of ignition coil at connector plug for Idle Stabilizer Control Unit.
Connect US 1115 L.E.D tester between terminals 5 and 17 of connector
plug. L.E.D. tester should flash while cranking.

If YES: - replace the idle stabilizer control unit and proceed.

If NO: - repair open circuit between terminal 1 of ignition coil and
terminal 17 of idle stabilization control unit plug.

If you have no milliamp reading and idle is low and/or surging, check
for power to idle stabilization  control unit from terminal 87 of the
power supply relay. Connect US 1115 L.E.D. tester between terminals 5
and 14 of idle stabilization control unit plug. L.E.D. tester should
come on when ignition is switched on.

If NO: repair open circuit between terminal 87 of power supply relay and
terminal 14 of the idle stabilization control unit plug.

Part II: