Volkswagen Golf/Jetta 2 manual

Idle speed and mixture (CO content) - testing
Fuel and exhaust systems - Mono Jetronic fuel injection / Idle speed and mixture (CO content) - testing

1 The prerequisites for this test are that the ignition timing must be correct and the engine must be at its normal operating temperature.

During the test, all electrical circuits including the engine cooling fan and, where applicable, the air conditioning, must be switched off.

2 The ignition must be switched off before the test meter is attached to check engine speed.

An exhaust gas analyser must be used to check the CO content from the exhaust.

3 The idle speed and mixture are not adjustable on this system and if they are not as specified, all that can be done is to inspect the various fuel system and associated vacuum electrical connections to ensure that they are in good condition and securely connected. If found to be in good condition, it will be necessary to have the system checked out by a VW dealer using specialised testing equipment to identify and rectify the fault.

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