ENGINE  275.950 /980 in MODEL 215

The ME-SFI gasoline injection and ignition system is a further development of the LH and DI and HFM systems, respectively. The abbreviated designation ME-SFI 2.7.1 means: M = Motronic (motor electronics) E = Electronic accelerator pedal (electronic accelerator) 2.7.1 = Version (further version e.g. 1.0, 2.0, 2.1, 2.7 or 2.8) The following functions are combined in the ME-SFI control unit: Ignition system Injection system Electronic accelerator/cruise control/idle speed control Diagnosis/fault storage Drive authorization system/immobilizer Emission control system

Gasoline injection system The fuel is injected by electromagnetic fuel injectors. These are actuated sequentially by the ME-SFI control unit, in other words an injector is assigned to each cylinder which meters the quantity of fuel computed for the cylinder. The main measurement for determining the fuel measure is the intake manifold pressure (load detection). It is detected by means of the pressure sensor downstream of throttle valve actuator (B28/7). A performance map dependent boost pressure control protects the engine against overload.

The ME-SFI control unit essentially analyzes the following information: Coolant temperature Engine speed and crankshaft position Camshaft position Throttle valve position Charge air temperature Accelerator pedal position Vehicle speed (via CAN) Knock identification O2-sensor signals Oil level, oil temperature and oil quality Atmospheric pressure (in the ME-SFI control unit) Air pressure downstream of air filter, right and left cylinder bank Boost pressure (upstream of throttle valve actuator) Intake manifold pressure (downstream of throttle valve actuator) Idle speed control The idle speed is controlled by the throttle valve actuator, which is operated by the ME-SFI control unit, by altering the position of the throttle valve.

Electronic accelerator No mechanical link between accelerator pedal and throttle valve actuator. The accelerator pedal sensor detects the accelerator pedal input for the ME-SFI control unit. Transmission shift delay The shift points of the automatic transmission are delayed in line with temperature, vehicle speed and time in order to more rapidly heat up the catalytic converter to its operating temperature. ECI ignition system The ECI ignition system is an ac voltage ignition system with each one ignition module for the right and left cylinder bank and a common power pack. Two spark plugs are assigned to each cylinder. The high voltage is distributed without the use of moving parts, directly by the ignition coils to the spark plugs (rotorless high voltage distribution). The anti-knock control (AKC) function is integrated in the ME-SFI control unit. Knock identification is performed via four knock sensors.

CAN databus Depending on equipment and model the following control units are networked over the CAN: ME-SFI control unit ETC [EGS] control unit ESP, SPS [PML] and BAS control unit SBC control unit (model 230, 240) Electronic selector lever module control unit AAC [KLA] control and operating unit Restraint systems control unit EIS [EZS] control unit FBS control unit DTR control unit Steering column module Instrument cluster SAM control unit with fuse and relay module for the driver (model 240) SAM control unit with fuse and relay module for the passenger (model 240) Rear 2 SAM control unit with fuse and relay module (model 240)

Enabling of engine control An engine start is only possible in combination with a drive authorization system (DAS 3). The ME-SFI control unit is networked with the DAS via the CAN.

	Motor electronics (ME-SFI) gasoline injection and ignition system - arrangement of components	Location of components at engine end	GF07.61-P-0001-01MA
		Model 215 with Engine 275.950/980	GF07.61-P-0001-01KM
	Motor electronics (ME-SFI) gasoline injection and ignition system function diagram		GF07.61-P-0001-02M
	Motor electronics (ME-SFI) gasoline injection and ignition system control unit input signals		GF07.61-P-0001-06M
	Motor electronics (ME-SFI) gasoline injection and ignition system control unit output signals		GF07.61-P-0001-07M
	ME-SFI gasoline injection and ignition system model and component installation survey		GF07.61-P-0001-12M
	Ignition ON, ME-SFI function		GF07.61-P-3005M
	Starting, ME-SFI function		GF07.61-P-2003M
	Idle speed, ME-SFI function		GF07.61-P-2006M
	Driving mode, ME-SFI function		GF07.61-P-2005M
	Diagnosis fault memory, ME-SFI function		GF07.61-P-2004M
	CAN data bus, function		GF54.00-P-0005M
	ME-SFI pneumatic diagrams		PP07.61-P-5000M
	ME-SFI vehicle features	Comparison of engine 275.950/951	AH07.61-P-0002-02MM
		Comparison of engine 275.950/951 with engine 275.98 (AMG)	AH07.61-P-0002-02MA
		Comparison of engine 285.950 with engine 285.980	AH07.61-P-0002-02MB
			AH07.61-P-0002-02MU
	Contents, function description of drive authorization system, stage 3 (DAS 3)		GF80.57-P-0999SZ
	Motor electronics (ME-SFI) gasoline injection and ignition system - survey of system components, location/task/design/function		GF07.61-P-9999M