Fuel system — checking and adjustment (BMW 3 Series E46)

Examination

1. If a fault has occurred in the fuel injection system, first of all check the reliability of the electrical connections and the absence of corrosion in them. Make sure that the occurrence of the fault is not associated with insufficient maintenance of the engine, i.e. the air filter is sufficiently clean, the spark plugs are in good condition and the gaps in them are correctly adjusted, the compression in the cylinders is within acceptable limits, that the crankcase ventilation hoses are not damaged or clogged with dirt.

2. If these checks do not reveal the cause of the malfunction, then take the car to a specialized service station for testing using a special diagnostic device. The car has a diagnostic connector into which this device is connected. The system connector on some models is located above the upper support of the right front suspension (fig. 10.2.a, b), while on other models it can be installed under the front panel on the driver's side next to the 16-pin on-board diagnostics connector. The device will quickly and easily determine the location of the fault and save you from the tedious procedure of sequential search. In addition, the device will not damage the system elements, while even a simple tester is dangerous for it, especially for the ECU.

Adjustment

3. An experienced car enthusiast with the necessary instruments and equipment, including a tachometer and gas analyzer, can check the CO level in the exhaust gases and idle speed. But if the specified parameters are outside the permissible limits and require adjustment, this can only be done by a dealer or a service station specialist with the appropriate equipment.