Smooth engine running analysis function - GF07.61-P-3034F
ENGINE 104.943 /944 /991 /994 as of 1.8.96
ENGINE 104.995 as of with CODE (494a) USA version with CODE (498) as of Model Year 97 Japan version
ENGINE 104.941 as of 1.8.96
ENGINE 111.943 /947 /951 /952 /955 /956 /957 /958 /973 /982 /983, 111.944 /975 as of 1.8.96, 111.946 as of 1.6.98, 111.921 /942 as of 1.9.98
ENGINE 111.945 in MODEL 208.335/435 as of 1.6.98, 202.020 /080 as of 1.9.98
ENGINE 111.974 with CODE (494a) USA version
ENGINE 112.910 /911 /912 /913 /914 /916 /917 /920 /921 /922 /923 /940 /941 /942 /943 /944 /946 /947 /949 /953 /954 /955 /970 /972 /973 /975
ENGINE 113.940 /941 /942 /943 /948 /960 /961 /963 /965 /966 /967 /968 /969 ENGINE 119.980 /981 /982 /985
ENGINE 120.982/ 983
Shown on Engine 119
Engine running is constantly monitored in order to protect the catalytic converter from excessive thermal stresses if combustion misfiring occurs.
If the smooth engine running analysis in the ME-SFI control unit detects combustion misfiring, the appropriate injector or injectors are no longer actuated after a certain number of misfirings.
Smooth engine running signal
What is detected is combustion misfiring caused by:
- Ignition system
- Injection system
- Engine mechanics (e.g. fresh air, valve seat, valve springs, defective shift rocker arms on Engine 113 with cylinder shutoff)
The following factors are taken into account:
- Engine speed, engine load
- Detection of road bumps
- Synchronization of injection and firing order
- Fuel reserve signal
- Sensor rotor adaptation performed
- Sensitivity (adjustable with HHT/STAR DIAGNOSIS)
- Engine 113.960 with cylinder shutoff: Cylinder shutoff ON or OFF
- Engine speed, engine load
A comparative value for the time between two combustions is formed from these parameters.
- Recognition of uneven road surface
Up to 5/96 the body acceleration sensor is installed. As of 6/96 the signal is supplied over the CAN by the vehicle dynamic systems on the basis of the wheel speed (uniform running).
On poor road surfaces the smooth engine running analysis is set more sensitive. Vibrations transmitted through the drive train may have a negative influence on the analysis at certain engine speeds and load states.
- Synchronizing fuel injection and firing order
The cylinder recognition is required for storing and -assessment as well as the selective cylinder shutoff.
- Fuel reserve signal
If combustion misfiring has been detected, a fault is stored if the fuel tank level is too low. Combustion misses due to fuel starvation are detected via this additional information.
- Sensor rotor adaptation
The smooth engine running analysis is not active until sensor rotor adaptation has been completed. In a deceleration phase (uniform smooth running) the smooth engine running analysis stores the particular smooth running properties of the engine. These are required as a comparison parameter for detecting misfiring.
- Misfiring counters
Any misfiring detected is entered in the fault memory in the following counters:
- Total of all misfiring
- Misfiring at specific cylinder
- Misfiring at "emission limit"
- Misfire, damaging to TWC
The smooth engine running analysis replaces the measurement of the combustion period and combustion voltage.
| Motor electronics control unit, location/task/design/function | other than engine 111 EVO | GF07.61-P-5000F | |
| Engine 111 EVO | GF07.61-P-5000GS | ||
| Acceleration sensor, location/task/design/function | Engine 119, 120 up to 7/96 | GF07.04-P-4102L | |
| Crankshaft position sensor, location/task/design/function | GF07.04-P-4116F | ||
| Camshaft Hall sensor, location/task/design/function | GF07.04-P-4117F | ||
| Hot film mass air flow sensor, location/task/design/function | Engine 104, 111, 112, 113, 137 | GF07.07-P-4118G | |
| Engine 111 EVO | GF07.07-P-4118GS | ||
| Engine 119, 120 (round connector) | GF07.07-P-4118E | ||
| Fuel injector, location/task/design/function | GF07.03-P-5004F | ||
| ME-SFI synchronizing fuel injection and firing order function | other than engine 111 EVO | GF07.61-P-4009F | |
| Engine 111 EVO | GF07.61-P-4009GS | ||
| CAN data bus, function | Vehicles with CAN | GF54.00-P-0005F | |
| ME-SFI fuel reserve signal function | GF07.61-P-4025-01F | ||
| ECI ignition system function | Engine 137 | GF15.15-P-3000L |