Volkswagen Golf/Jetta 2 manual

Idle switch control valve - testing
Fuel and exhaust systems - Mono Jetronic fuel injection / Idle switch control valve - testing

This device is attached to the throttle position sensor (see illustration) and its function is to control the ignition timing vacuum advance. If defective, it can cause problems with the idle speed and/or the overrun cut-off.

A simple test can be made by switching on the ignition, then opening and closing the throttle valve. Listen to hear if the control valve clicks twice. If this is proved to be in order, start the engine, allow it to idle and then momentarily detach the wiring connector from the control valve and reconnect it. The idle speed should momentarily increase and then drop back to normal. If not, the control valve is faulty and should be renewed.

6.1 Injector, ECU and associated components
6.1 Injector, ECU and associated components

1 Series resistor
2 Vacuum hose
3 Fixing screw
4 Temperature regulator
5 Poppet valve
6 O-ring
7 Injector unit
8 Connector
9 Electronic Control Unit (ECU) 10 Spacer
11 Flap vent
12 Idle switch control valve 13 Vacuum pipe
14 Fuel return pipe
15 Fuel feed pipe

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