What are the causes of unstable idle speed in a BMW 523?
1 Answers
The main causes of engine idle speed fluctuation include: ignition electrical faults, such as ignition coils, spark plugs, etc.; fuel supply issues, such as excessively low or high fuel pressure, fuel pump, fuel filter, fuel injectors, etc.; intake system leaks; sensor failures, such as the front oxygen sensor, coolant temperature sensor, camshaft/crankshaft position sensor, VANOS, etc.; power supply problems, such as unstable generator output; and DME control module faults. Methods to reduce fuel consumption: The longer the idle time while parked, the higher the fuel consumption, so try to minimize idle parking time. Factors affecting fuel consumption: Various operating conditions such as acceleration, deceleration, braking, and engine idling.