ME-SFI synchronization of fuel injection and firing order, function - GF07.61-P-4009MIS

ENGINE 272.9 in MODEL 221.0 /1 as of model year 2009/ AEJ 08 

ENGINE 273.9 in MODEL 216.3, 221.0 /1 as of model year 2009/ AEJ 08 

Function requirements synchronization of fuel injection and firing order, general points 

• Circuit 87M ON (engine control ON)
• Engine running

Synchronization of the fuel injection and firing order, general points 

Synchronization of the injection and firing order is processed by the ME-SFI [ME] control unit in order to actuate the ignition coils (T1) and fuel injection valves (Y62)N3/10

Furthermore, the synchronization is required for the knock control and the fuel shutoff on the individual cylinders.

The ME-SFI [ME] control unit synchronizes the injection and firing using the signals from the following sensors:

• Crankshaft Hall sensor (B70), engine speed and crankshaft position
• LH and RH intake camshaft Hall sensors (B6/4, B6/5), intake camshaft positions
• LH and RH exhaust camshaft Hall sensors (B6/6, B6/7), exhaust camshaft positions

Function sequence for synchronization of the fuel injection and firing order 

When the engine is started, the injection sequence is determined according to the firing order, using the voltage signals from the crankshaft Hall sensor and the intake camshaft or exhaust camshaft Hall sensors. To do this, ignition TDC (Top Dead Center) must be detected in cylinder 1.

At the 2nd negative signal edge following the gap in the signal from the crankshaft Hall sensor, the ME-SFI [ME] control unit detects the TDC position in cylinders 1 and 6. If the signal from an intake camshaft Hall sensor is at 0 V (low) at this time, the ME-SFI [ME] control unit processes it to detect ignition TDC in cylinder 1.

If the voltage pulse is missing from a camshaft Hall sensor the voltage pulse will be used as a substitute in a certain sequence by another camshaft Hall sensor for recognition of the ignition TDC of cylinder 1.

If no voltage signal is available from any of the camshaft Hall sensors, ignition and injection take place after 360° CKA (C  ranK A  ngle) in order to allow an emergency start.

When the engine is shut down, coasting detection takes place, which also evaluates the engine turn back shortly before standstill. During a computer run on by the ME-SFI [ME] control unit, the found rest position of the crankshaft as a °crank angle is stored and used for the next engine start. If coasting detection does not produce a result, or the engine has been turned while shut down, injection and firing order are synchronized at engine start.

Signal assignment engine 272 

Signal assignment engine 273 

	Electrical function diagram for synchronization of injection and firing order ME	Model 216		PE07.61-P-2771-97CAB
	Component description for ME-SFI [ME] control unit	N3/10	Engine 273	GF07.61-P-6000MLS