ME-SFI overrun fuel shutoff, function - GF07.61-P-4019AMG
ENGINE 156.980 in MODEL 164, 251 up to Model Year 8
ENGINE 156.982 in MODEL 209
ENGINE 156.983 in MODEL 211, 219
ENGINE 156.984 in MODEL 216, 221 up to Model Year 8
Deceleration fuel shutoff has the following tasks:
- Increasing the braking power of the engine in the overrun mode
- Reducing fuel consumption
- Improve exhaust characteristics in overrun
In overrun mode, the ME-SFI [ME] control unit switches off the fuel injection valves depending on the coolant temperature and engaged gear, if:
- Accelerator pedal is not operated (detection on the basis of actual value signals from the accelerator pedal sensor)
- Vehicle not in Cruise control/Distronic mode
The fuel injection valves are switched on again when the accelerator pedal is operated.
In order to prevent a sudden torque rise when combustion is reestablished after deceleration fuel shutoff, ignition timings are briefly adjusted towards "retarded".
After overrun mode the mixture is enriched for a short time in order to free up the catalytic converters from the increased oxygen. The valve overlap is also set to its minimum value by the camshaft adjustment. This ensures that an optimal exhaust conversion rate is more rapidly achieved.
The engine speed on reestablishment of combustion is dependent on the coolant temperature, the engine and transmission design and the engaged drive position.
The overrun fuel shutoff is locked out for drive position "P" or "N" and for excessively high exhaust gas temperatures. The high oxygen content in the exhaust gas for overrun fuel shutoff leads to increased oxidation of carbon monoxide and hydrocarbon (afterburning). The heat so generated can overheat the catalytic converters.
| Component description for adjustable camshaft timing solenoid | Y49/4, Y49/5, Y49/6, Y49/7 | GF05.20-P-2100AMG |
| Component description for fuel injection valves | Y62y1-Y62y8 | GF07.03-P-6010AMG |
| Component description for camshaft Hall sensor | B6/4, B6/5, B6/6, B6/7 | GF07.04-P-6020AMG |
| Component description for coolant temperature sensor | B11/4 | GF07.04-P-6040AMG |
| Component description for the crankshaft Hall sensor | B70 | GF07.04-P-6220AMG |
| Component description for the ME-SFI [ME] control unit | N3/10 | GF07.61-P-6000AMG |
| Component description for ignition coils | T1/1-T1/8 | GF15.10-P-2100AMG |
| Component description for the accelerator pedal sensor | B37 | GF30.20-P-2010AMG |