Volkswagen Golf/Jetta 2 manual

Auxiliary air valve - testing
Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines / Auxiliary air valve - testing

1 To carry out this test, the engine coolant temperature must be below 30°C.

2 Detach the distributor HT lead.

3 Detach the auxiliary air valve electrical plug and ensure that the contacts in the plug connector are in good condition (see illustration).

10.3 Auxiliary air valve (arrowed)
10.3 Auxiliary air valve (arrowed)

4 Connect up a voltmeter across the contacts of the plug connectors, start the engine and run at idle speed. The voltage reading must be a minimum of 11.6 V. If a voltmeter is not available, a test lamp will suffice to check the voltage supply.

5 With the auxiliary air valve electrical plug still detached, leave the engine running at idle speed and pinch the air inlet duct-to-auxiliary valve hose. The engine speed should drop.

6 When the engine is warmed up to normal operating temperature, reconnect the auxiliary valve plug then pinch the hose again. This time the engine speed should remain unaltered.

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