Golf III L4-1984cc 2.0L SOHC (1993)
Throttle Body: Testing and Inspection
Throttle Valve Adjusting Screw
1.
The factory-set Throttle Valve adjusting screw is not used to adjust idle speed. Its only function is to provide a mechanical stop for the linkage to
prevent damage to the throttle plate and housing. It should be adjusted only if the factory setting has been tampered with or changed.
Throttle Valve Vacuum Hoses Digifant II
2.
To check the adjustment, disconnect the vacuum line from the carbon canister control valve and connect a vacuum gauge to the vacuum port. At
idle there should be approximately zero vacuum. Up to 1 in. vacuum is acceptable. If the vacuum gauge measures greater than 1 in. at idle, the
throttle valve basic adjustment should be corrected. Refer to ADJUSTMENT PROCEDURES.
3.
Check the vacuum hose fittings at the throttle valve for proper vacuum signal as some fittings can become plugged, this is due to the introduction
of PCV vapors near the throttle valve. If signs of PCV residue are found, remove the intake air hose and visually check the throttle valve. Clean
the vacuum fittings and throttle valve with suitable spray type cleaner as needed.
