Adjusting and Testing

IDLE STABILIZATION, ADJUSTING

Requirements:
- engine cold
- A/C switched OFF
- all other electrical consumers switched OFF





- attach multimeter US 1119, using VW 1315A/2 adaptor to idle stabilization valve, switch to 2A scale
- switch ON ignition
- 945 - 1055 mA

IF NO
- replace control unit
- start engine and warm up to 80°C (176°F) oil temperature, with A/C switched OFF
- idle stabilizer mA value should be: 430 ± 20 mA

NOTE: If readings are 480 ± 25 milli-amps with auto transmission or 490 ± 25 milli-amps with manual transmission, check for wire break between control unit and ignition coil terminal 1.

- specification with A/C ON automatic transmission 500 ± 20 milli-amps
- specification with A/C ON manual transmission 490 ± 20 milli-amps





IF NO
- adjust throttle by-pass screw (arrow) until 430 ± 20 mA is obtained
- check idle speed 800 ± 70 RPM





THERMOSWITCH, CHECKING
- pull off connector and attach multimeter US 1119 to thermoswitch
- specification: up to 20°C (68°F) = 0 Ohms
above 40°C (104°F) Ohms

IF NO
- replace thermoswitch

IDLE STABILIZATION SYSTEM, CHECKING
- engine oil temperature approx. 50°C (122°F)

WORK SEQUENCE





- pull connector off control valve for idle stabilization and attach multimeter US 1119
- switch ignition ON
- specification: approx. battery voltage
- re-connect connector to control valve
- working vibration must be felt when touching idle stabilization control valve
IF NO
- replace idle stabilization control valve
- if battery voltage is not shown, check for wire break as follows:
- turn on ignition





- connect multimeter US 1119 between contact 14 of socket 11 and contact 5 of socket 12 on relay plate
- specification: approx. battery voltage





- turn air conditioner ON
- connect multimeter US 1119 between contact 2 and socket 12 on relay plate and ground
- specification: approx. battery voltage




- connect multimeter US 1119 between contact 11 of socket 11 and connector of idle stabilizer control valve
- specification: 0.0 ohms





- connect multimeter US 1119 between contact 4 of socket 12 and connector of idle stabilizer control valve
- specification: 0.0 ohms





- pull throttle valve switch connector apart
- connect multimeter US 1119 between connector and ground
^ specification: approx. battery voltage





- pull off throttle switch connector and attach multimeter US 1119
^ Gspecification: throttle in idle position = 0.0 ohms
throttle slightly open = infinite ohms (adjust if necessary)





- connect multimeter US 1119 between contact 13 of socket 11 and thermoswitch wire (brown/black)
^ specification: 0.0 ohms

If specification OK but idle stabilization NOT OK (engine speed varies):
- replace control unit