Saturday, September 8, 2012
1989 Volkswagen Golf I – System/Component Tests
Prior to testing separate components or systems, it is highly recommended that all procedures listed in F – BASIC TESTING article be performed. Since many computer controlled and monitored components will change voltage and resistance valves if they malfunction, it is also recommended that connector pin check diagnosis be performed.
NOTE: Testing of individual components does not isolate possible shorts or opens in the control harness of electronically controlled systems. Use an ohmmeter to isolate shorts or opens in harness. All voltage tests should be performed with a Digital Volt Ohmmeter (DVOM) with a minimum 10-megaohm input impedance, unless specifically stated different in testing procedures.
ENGINE SENSORS & SWITCHES Airflow Sensor (Cabriolet & Fox)
1) Start engine to pressurized fuel system. Turn engine off and remove intake boot from top of airflow sensor. Disconnect coil secondary wire from coil and jumper to ground.
2) Check sensor play by slowly moving plate through travel range with a magnet. Resistance should be felt. Move plate back to the rest position. There should be no resistance. If binding is felt, loosen sensor plate hold-down bolt and adjust plate to center of venturi.
3) If resistance is uneven, remove airflow sensor from housing to clean and lubricate lever assembly. If resistance is caused by control plunger, remove and clean control plunger assembly. If binding continues, replace fuel distributor.
4) Check position of airflow sensor plate. Airflow sensor plate edge must be within .075? (1.9 mm) below the narrowest section of the venturi. See Fig. 1. If not, bend sensor spring until correct specification is obtained. Ensure that there is a small gap between the sensor lever and the control plunger.