Overrun Mode Fuel Shutoff, Basic Function - GF07.10-P-1049A

Engine all (CAR)

General

The overrun mode fuel shutoff interrupts the fuel supply to the combustion engine under certain driving conditions in order to reduce fuel consumption, increase the braking effect of the combustion engine and improve the exhaust characteristics. The combustion produces no further output so that the vehicle is only rolling.

Function requirements

Engine management ON (circuit 87M)
Engine in operation
Accelerator not operated
Transmission position D or R engaged
Transmission position N engaged (when the vehicle is at a standstill or rolling)
Speed control or distance control not active
Not too high an exhaust temperatures

Function

If the accelerator pedal is not operated, the overrun mode fuel shutoff automatically comes into operation.

The combustion engine control unit no longer actuates the fuel injectors, depending on the input signals of the coolant temperature, selector lever position and engine speed. With a diesel engine, the combustion engine control unit reduces the fuel quantity and accordingly the fuel pressure in the fuel distributor, also via the quantity control valve.

When the accelerator pedal is operated, the combustion engine control unit actuates the fuel injectors again. With a diesel engine, the combustion engine control unit also increases the fuel quantity and the fuel pressure in the fuel distributor via the quantity control valve.

Function schematics
Function schematic for overrun mode fuel shutoff	Engine 260, 282, 608 in model 118, 177, 247 Engine 264 in model 167	PE07.10-P-2508C
	Engine 654 in model 118, 177, 247 Engine 654, 656 in model 167	PE07.10-P-2508D
	Engine 256 in model 167	PE07.10-P-2508E
	Engine 176 in model 167	PE07.10-P-2508B
	Engine 139 in model 118, 177	PE07.10-P-2508F
Control units
Combustion engine control unit, basic function		GF07.08-P-9890A