Turn off all electrical consumers. If there are any, also the air conditioning system.
Connect the crankshaft speed meter.
Attention: Connect the device only when the ignition is off.
Check the ignition timing.
Connect the CO measuring device. In cars with a catalytic converter, connect the device to the CO sampling tube in the engine compartment. The sampling tube is located on the outlet pipe and is usually closed with a blue cap.
Caution: Place the measuring instrument hose firmly on the sampling tube. Make sure that no leakage occurs.
Check if the air damper is fully open (carburetor upper flap). If necessary, adjust the automatic fuel mixture enrichment device at start-up or ensure the flap's mobility. To do this, unscrew the intake air guide casing and then put it back in place.
Disconnect the crankcase ventilation hose from the cylinder head and position it so that it can only suck in fresh air. Before removing, cut the hose clamp with side cutters.
Start the engine and leave it running at idle. Check the idle speed of the crankshaft and the CO content.
Prescribed values: rotation speed - 800 ±50 1/min; cO content - 1.0 ±0.5% by volume.
Adjustment
Remove the protective cap from the CO content adjustment screw.
The prescribed values are set by alternately rotating the idle speed adjustment screws "A" and the CO content "B".
Note: During the adjustment process, the cooling system fan must not rotate.
Disconnect the measuring instruments with the ignition off.
Place the blue rubber cap on the CO sampling tube.
Cover the CO content adjustment screw with a protective cap.
Connect the crankcase ventilation hose to the cylinder head and secure it with a clamp.
Note: If the CO content has now increased, the reason is not incorrect adjustment, but rather the enrichment of the combustible mixture due to the influx of gasoline vapors from the crankcase, where gasoline gets mainly during short-distance trips.
During long, continuous trips, the proportion of gasoline in the engine oil decreases, and the CO content in the exhaust gases returns to normal. This can also happen quickly after about a 30-minute trip or another oil change.
(The original can be viewed on the portal: www.VWManual.ru)
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