Engine With One Knock Sensor

Requirements:
Engine at normal operating temperature, 80°C (176°F).
All electrical consumers (A/C, rear window defroster, etc.).
Radiator fan must not be running while checking or adjusting.
No fuel preassure gauges connected to the fuel system.
Throttle valve in the proper idle position.
Throttle valve switch must be adjusted properly and working.
Exhaust system must be tight and free from leaks.
Oxygen sensor system in good working order.
NOTE; If the injection lines were loosened or replaced, run the engine up to at least 3000 RPM several times to clear the system of trapped air before making adjustments.

1. Initial setup
a. Remove the cap from the charcoal canister 'T' fitting (located near the fuel distributor).
b. Remove the breather hose from the elbow fitting at the valve cover. Plug the hose that is still connected to the valve cover.
c. Connect an exhaust gas analyzer to the exhaust manifold sampling port.
d. Connect a tach-dwell meter to the engine.
e. Disconnect the idle stabilizer valve harness plug, and install a test harness (VW 1315 A/2 or equivalent) between the valve and the harness connector.
f. Connect a multimeter to the test harness, set to 2 Amp range.

2. Set Idle Speed
a. Start the engine and let it idle.
b. Idle speed should be;
Manual Trans. ......... 800 +/- 50 RPM
Automatic Trans. ...... 720 +/- 50 RPM
c. If the idle speed is not within specification, adjust the speed by turning the throttle bypass screw in the throttle housing.
d. Disconnect the green wire from terminal 1 of the ignition coil junction block (located on the ignition coil) to activate the idle stabilizer preset value.
e. Idle valve current reading should be 430 +/- 20 mA
f. Reconnect the green wire to the ignition coil terminal block.
g. Idle valve current should be 430 +/- 20 mA and fluctuating, and the idle speed should remain within specifications.