Checking and adjusting the crankshaft speed of a cold engine at idle speed (VW Passat B3)

The throttle clearance can also be adjusted by means of the cold engine idle speed. The advantage of this method is that the carburetor does not need to be removed to perform the adjustment. The cold engine idle speed should only be checked or adjusted if the engine's transient response to the accelerator pedal is unsatisfactory or if the cold engine responds poorly to the pedal.

Warm up the engine to operating temperature, engine oil temperature not less than +60°C.

With the ignition off, connect a device to measure the engine speed.

Check idle speed adjustment, see above.

Check the ignition timing, see chapter "Ignition system".



Open the throttle valve by pressing the gas pedal and bringing the crankshaft speed to 2500 1/min. Press the stepped washer "1" down until it stops (arrow) and move the throttle valve back (the adjusting screw is on the second, higher step of the stepped washer).

In this case, the crankshaft speed must correspond to the so-called cold engine idle speed. The prescribed value is 1700 ±50 1/min.



If necessary, adjust the cold engine shaft speed using adjusting screw "2".

[The original article is posted on the website: www.vwmanual.ru]