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

ENGINE 113.990 in MODEL 211, 219 

ENGINE 113.991 in MODEL 215, 220 

ENGINE 113.992 in MODEL 230 up to Model Year 2008 

ENGINE 113.993 in MODEL 463 up to 31.5.12 

ENGINE 113.995 in MODEL 230 up to Model Year 2008 

Fig 1: Identifying ME-SFI Synchronization Of Fuel Injection Function Diagram
G07870966Courtesy of MERCEDES-BENZ USA

When the engine is started, the injection sequence in line with the firing order is defined on the basis of the signals supplied by the crankshaft position sensor and the camshaft Hall sensor.

Signal assignment 

Fig 2: Identifying ME-SFI Synchronization Of Fuel Injection Signal Assignment
G07870967Courtesy of MERCEDES-BENZ USA

When the crankshaft is rotating, an alternating voltage is generated in the crankshaft position sensor by the teeth of the driven plate.

During this operation, each tooth generates an alternating voltage signal. No voltage is generated as a result of the gap created by 2 missing teeth.

The engine control unit detects the TDC position of cylinders 1 and 6 with the 2nd negative slope after the gap.

If, at this moment, the signal from the camshaft Hall sensor is at 0 volt ("low") the ME control unit processes this in order to detect ignition TDC of cylinder 1.

Synchronization of the injection and firing order is processed by the ME-SFI control unit for actuation of the ignition coils and the fuel injection valves.

In addition the synchronization is required for the anti-knock control and the fuel cut-off on the individual cylinders.

  Fuel injection valve, location/task/design/function   GF07.03-P-5004KE
  Crankshaft position sensor, location/task/design/function   GF07.04-P-4116AM
  Camshaft Hall sensor, location/task/design/function   GF07.04-P-4117HA
  ME-SFI control unit, location/task/design/function   GF07.61-P-5000AM 
  Spark plugs, location/task/design/function   GF15.10-P-3101AM
  Ignition coils, location/task/design/function   GF15.10-P-3102AM