ME-SFI System Function
Motor electronics (ME-SFI) fuel injection and ignition system function
ENGINE 104.941 /943 /944 /991 /994as of 1.8.96
ENGINE 104.995
with CODE (494a) USA version
with CODE (807) Model year 1997
with CODE (808) Model year 1998
ENGINE 111.921 /942 as of 1.9.98,
111.943,
111.944 as of 1.8.96,
111.946 as of 1.6.98,
111.947 /973,
111.975 as of 1.8.96
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
with CODE (807) Model year 1997
with CODE (808) Model year 1998
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
ENGINE 137.970
ME control unit input signals, shown on engine 119
A16 Knock sensors
B2/5 Hot film mass air flow sensor
B6/1 Camshaft Hall sensor
B11/4 Coolant temperature sensor
B17 Intake air temperature sensor
B24/7 Body acceleration sensor (up to 5/96)
B37 Accelerator pedal sensor
G3/3 Left O2 sensor, upstream TWC
G3/4 Right O2 sensor, upstream TWC
K40 Relay module
L5 Crankshaft position sensor
M16/1 Electronic accelerator (EA)/cruise control (CC) idle speed control (ISC) actuator
N3/10 ME-SFI [ME] control unit
N16/1 Base module
N19 AAC control unit
N22 AAC [KLA] control and operating unit
N47-1 ASR/SPS control unit
N47-5 ESP, SPS [PML] and BAS control unit
S9/1 Stop lamp switch
S40 CC [TPM] switch
S43 Oil level check switch (oil pan right side)
CAN Data bus
B Connection via CAN to the ETC [EGS] control units (N15/3), ASR/SPS (N47-1), ESP/SPS (N47-5, SA), IFRCL (N54)
ME control unit output signals, shown on engine 119
55 Fuel filter 75 Fuel tank 77 Activated charcoal canister
A1e43 EPC malfunction indicator lamp (electronic power control)
K27 Fuel pump relay module
K40 Relay module
M3 Fuel pump
M16/1 Electronic accelerator (EA)/cruise control (CC) idle speed control (ISC) actuator
N3/10 ME control unit
G3/3 Left O2 sensor upstream of TWC
G3/4 Right oxygen sensor upstream TWC [KAT]
T1/1-T1/8 Ignition coils
X11/4 Diagnostic data link connector, 38-pin
Y49/1 Left adjustable camshaft timing solenoid
Y49/2 Right adjustable camshaft timing solenoid
Y58/1 Purge control valve
Y62 Fuel injection valves
CAN Data bus
B Connection via CAN to the ETC [EGS] control units (N15/3), ASR/SPS (N47-1), ESP/SPS (N47-5, SA), IFRCL (N54)
F Fuel pump relay (K27), illustrated on model 140
g Relay module (K40), model 210
Section through cylinder plane engine 112, 113
12 Variable intake manifold
17 Fuel rail
19 Exhaust manifold, air gap insulated
22 Variable flap
R4 Spark plugs (dual ignition)
Y62 Injector
The ME fuel injection and ignition system is a further development of the LH and DI and HFM systems, respectively.
The abbreviated designation ME 1.0 means:
M = Engine
e = Electronics
1.0 = Version
(further version e.g. 2.0, 2.1, 2.7, 2.7.1 or 2.8)
The following functions are combined in the ME-SFI control unit:
- Fuel injection
- Ignition
- Electronic accelerator with cruise control and idle speed control
- DTC memory/diagnostic system, complying with EURO3/4 or OBD II for (USA)
- Drive authorization system.
Fuel 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 air mass is the main measured quantity for determining fuel metering. It is detected through the hot film mass air flow sensor or through the boost pressure sensor (when charging).
The ME control unit essentially analyzes the following information:
- Coolant temperature
- Air mass
- Engine speed
- Throttle valve position
- Intake air temperature
- Accelerator pedal position
- The vehicle speed
- Knock identification
- O2-sensor signals
- Ethanol share in fuel tank, only (USA) Flexible Fuel Vehicle (FFV).
Idle speed control
The idle speed is controlled by the throttle valve actuator, which is operated by the ME control unit, by altering the position of the throttle valve.
Camshaft adjustment
The inlet side camshaft of the engines 104, 111, 119 and 120 is adjusted on an electronic mapped basis by the ME-SFI control unit in the mid and upper engine speed and load range in order to boost the torque and power output.Engine 137 with one camshaft per cylinder bank also has camshaft adjustment.
CAN data bus
Dependent on year of construction, equipment and Model, control units are cross-linked via CAN. For example:
- RCL control unit
- ME control unit (Engine 120: left ME control unit and right ME control unit)
- AT control unit
- ABC control unit
- SBC control unit
- ETS/SPS [ETS/PML] control unit
- ESP / SPS
- Instrument cluster
- Electronic ignition switch.
Electronic accelerator
No mechanical link between accelerator pedal and throttle valve actuator. The pedal value sensor detects the accelerator pedal input for the ME-SFI control unit.
Transmission upshift delay (only AT and TWC)
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.
ENGINE 120
There are two independent fuel injection and ignition systems fitted. A separate ME control unit is installed for cylinder 1 to 6 (right cylinder bank) and for cylinder 7 to 12 (left cylinder bank).
Ignition system
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.
Engine 119, 120: an ignition coil is positioned above each spark plug.
Engine 111, 104: a twin spark ignition coil is installed for each two cylinders.
Engine 112, 113: two spark plugs and a dual ignition coil are installed for each cylinder.
Engine 137: alternating voltage ignition system with ignition module for right and left cylinder bank, dual ignition.