Controlling the amount of fuel injected during engine start-up (Mercedes-Benz Vito W639)

Fuel supply in starting mode does not depend on the position of the accelerator pedal. The starting mode is determined by the CDI system based on a coolant temperature below 80°C and an engine speed below 500 rpm.

In this mode, the CDI control unit generates control signals for the following system elements:

• pressure regulating valve (Y74);
• fuel injectors (Y76y 1 - Y76y4);
• fuel supply control valve (Y94).

In this mode the block receives the following information:

• Message from the E1S system control unit (N73) (air conditioning) about the presence of power in the Tml. 50 ON circuit.
• Temperature sensor signal via a separate line (B11/4).
• Accelerator pedal sensor signal via CAN-C multiplex network (B37/3).
• Engine speed signal via separate circuit (L5).
• Signal about the position of the automatic transmission selector from the gear selector unit (N15/5).

The system determines the end of the starting mode by turning off the starter. From this point on, fuel supply depends on the position of the accelerator pedal.