Diesel Idle Speed Adjustment (VW Passat B4)

. This adjustment must be performed on a warm engine (oil temperature not less than 60°C), with the fuel injection advance angle correctly set, with clean filter elements of the air and fuel filters, with free movement of the fuel injection advance angle correction cable during cold starting, with the cold engine start handle fully recessed, with the current consumers switched off.

Connect the control tachometer according to the operating instructions, start the engine at idle speed and check the crankshaft speed, which should be within the specified limits (tables 3-8 and 3-9).











If the idle speed deviates from the values specified in the tables, achieve the required value by turning the adjusting screw 1 (fig. 3-40, 3-41).







If it is impossible to adjust the idle speed of the crankshaft to less than 900 rpm for a diesel engine without turbocharging and less than 980 rpm for diesel engines with turbocharging by turning the screw, loosen the lock nut of the minimum idle speed limiting screw 3 (Fig. 3-40) or 2 (Fig. 3-41) and achieve the required value by turning screw 1, then tighten screw 3 until it touches the minimum idle speed limiting lever and tighten the lock nut.