DFI start quantity control function

P07.13-0299-79

A1e34 EDC malfunction indicator lamp

B11/4 Coolant temperature sensor

L5/6 Crankshaft position sensor

N3/8 DFI [EVE] control module

Y23/2y2 Check valve

Y23/2y4 Supply valve

Y23/2I1 Cam ring position sensor

Y23/2I2 Distributor shaft position sensor

S16/1 Starter lock-out/backup lamp switch

Y23/2 Distributor pump

Y23/2y1 Shut-off valve

Task

To regulate the start quantity depending on the operating condition and independent of the position of the accelerator pedal.

Function

The interior of the pump is under no presssure, the quantity control return spring (11/8) moves the distributor shaft (11) into the start position. The return spring of the start delivery plunger pushes the start delivery adjusting cam towards "RETARD". The shut-off valve (Y23/2y1) is open, the supply valve (Y23/2y4) closed. Turning the glow/starter switch (S2/2) to the start position activates the starter via circuit 50. The fuel pump (13) draws fuel from the fuel tank (80) via the fuel heat exchanger (60) and the main fuel filter (70/2). Increasing pressure pushes the delivery plunger (11/2) apart, making a large quantity of fuel available for starting. The overvoltage protection relay (K1) or the relay module (K40) supplies the DFI [EVE] control module (N3/8) with battery voltage via circuit 87+87U. The crankshaft position sensor (L5/6) detects the crankshaft position and the engine speed and delivers a signal to the DFI [EVE] control module (N3/8). The DFI [EVE] control module (N3/8) also receives coolant temperature data from the coolant temperature sensor (B11/4) and calculates the required start quantity. The distributor shaft position sensor (Y23/2I2) tells the DFI [EVE] control module (N3/8) the position of

the distributor shaft (11/1).

After the engine has started and at an engine speed of >600 rpm, the start quantity control does not operate.

The start quantity is regulated independently of the accelerator pedal position.Only after the engine speed exceeds 600 rpm (dependent on coolant temperature) can it be controlled using the accelerator pedal. The higher the coolant temperature the lower the start quantity released by the DFI [EVE] control module (N3/8).

The DFI [EVE] control module (N3/8) calculates the correct quantity for injection and the correct start of delivery using the input signals sent by the

Crankshaft position sensor (L5/6)

Coolant temperature sensor (B11/4)

Cam ring position sensor (Y23/2I1)

Distributor shaft position sensor (Y23/2I2)

It then controls these factors by means of output signals to the

Supply valve (Y23/2y4)

Check valve (Y23/2y2)

Adjusting valve (Y23/2y3)

The EDC MIL (A1e34) extinguishes shortly after the engine has started.

The following components and systems operate during starting.