Motronic DMEM 1.1-1.3 system diagram
1 - fuel tank;
2 - fuel pump;
3 - fuel filter;
4 - fuel pressure regulator;
5 - ignition coil;
6 - air flow meter;
7 - nozzle;
8 - ignition distributor;
9 - throttle potentiometer;
10 - electronic control unit (ECU);
11 - idle speed regulator;
12 - coolant temperature sensor;
13 - engine speed sensor;
14 - fuel accumulator with activated carbon;
15 - ventilation valve;
16 - relay for turning on the fuel pump.
Diagram of the Motronic DMEM 3.1 system (4 valve engines)
1 - fuel tank;
2 - fuel pump;
3 - fuel filter;
4 - fuel pressure regulator;
5 - ignition coil;
6 - air mass meter with a heated conductor;
7 - nozzle;
8 - spark plugs;
9 - throttle potentiometer;
10 - ECU;
11 - rotary idle control;
12 - coolant temperature sensor;
13 - knock sensor;
14 - engine speed sensor;
15 - fuel tank ventilation valve.
Diagram of the Motronic DME injection system (modern car models)
1 - container with activated carbon;
2 - blocking valve;
3 - fuel tank ventilation valve;
4 - fuel pressure regulator;
5 - nozzle;
6 - heating regulator;
7 - ignition coil;
8 - position sensor;
9, 10 - not used;
11 - air flow meter;
12 - control unit;
13 - throttle position sensor;
14 - idle speed controller;
15 - air temperature sensor;
16 - exhaust gas recirculation valve;
17 - fuel;
18 - knock sensor;
19 - speed sensor;
20 - engine temperature sensor (coolant);
21 - lambda probe;
22 - diagnostic plug;
23 - diagnostic lamp;
24 - pressure difference sensor;
25 - fuel pump.
BMW petrol engines are equipped with the Bosch Motronic injection system. This is a combined ignition and injection system, which is also referred to as DME (digital engine electronics). The ignition and injection systems are controlled from one control unit. This chapter mainly discusses the part of the system that is responsible for fuel injection.
DME is a stable system and needs no maintenance. Repairs are also very rare.