Ground, Power & Input/Output Circuits
Testing information is not available from manufacturer. See WIRING DIAGRAMS article to identify DME/Motronic control unit ground circuits, power circuits and input/output circuits. (Scheme 73) See DME ECU CONTROL UNIT LOCATION table.
Scheme 73
| Application | Location |
|---|---|
| 3-Series | Behind Cover On Right Rear Corner Of Firewall |
| All Others | Inside Box On Right Rear Corner Of Engine Compartment, Behind Strut Tower |
DME ECU CONTROL UNIT LOCATION
CRANKSHAFT (SPEED/POSITION PULSE) SENSOR
Crankshaft (speed/position pulse) sensor is located on front right side of engine, next to crankshaft pulley. See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS.
ENGINE (COOLANT) TEMPERATURE SENSOR
See ENGINE (COOLANT) TEMPERATURE SENSOR LOCATION table. See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS.
| Application | Location |
|---|---|
| 4-Cylinder | On Front Left Side Of Engine, Below Intake Manifold |
| 6-Cylinder | On Front Left Side Of Engine, Below Intake Manifold |
| V8 | On Front Of Engine, Near Idle Speed Control Motor |
ENGINE (COOLANT) TEMPERATURE SENSOR LOCATION
INTAKE AIR TEMPERATURE SENSOR
Intake air temperature sensor is mounted in intake manifold near mass airflow meter assembly. See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS.
RELAYS
For fuel pump relay, see FUEL DELIVERY under FUEL SYSTEM. For relay locations, see DME & FUEL PUMP RELAY LOCATION table.
| Application | Location | |
|---|---|---|
| Z3 | ||
| DME Relay | Under Left Side Of Instrument Panel, Next To Kick Panel | |
| Fuel Pump Relay | Right Rear Corner Of Engine Compartment, Next To DME ECU | |
| 3-Series (1) | ||
| DME & Fuel Pump Relays | Left Rear Corner Of Engine Compartment, In Relay Box | |
| 5-Series & 7-Series | ||
| DME Relay | Right Rear Corner Of Engine Compartment, Next To DME ECU | |
| Fuel Pump Relay | Right Side Of Trunk | |
| 8-Series | ||
| DME & Fuel Pump Relays | Right Rear Corner Of Engine Compartment, Next To DME ECU | |
| (1) (Scheme 74)and (Scheme 75). | ||
| (1) | (Scheme 74)and (Scheme 75). |
DME & FUEL PUMP RELAY LOCATION
Scheme 74
Scheme 75
FUEL DELIVERY
Note. For fuel system pressure testing, see BASIC TESTING article.
Fuel Pump Relay
Remove fuel pump relay. Apply battery voltage to relay terminals No. 30 and 86. (Scheme 76) Ground relay terminal No. 85. Voltage should now exist at relay terminal No. 87. Replace relay if it does not work as indicated.
Note. If relay does not work on vehicle, check battery feed, DME master (main) relay, DME/Motronic control unit and ground circuits going to fuel pump relay. See WIRING DIAGRAMS article in ENGINE PERFORMANCE. Only sockets No. 2, 4, 6 and 8 are used by relay.
Fuel Pressure Regulator
- Remove fuel pressure regulator. See «REMOVE/INSTALL & OVERHAUL»(ref-10054) article ENGINE PERFORMANCE section. Note code number and nominal pressure on fuel pressure regulator body. Install BMW Service Tester (133060) with connecting hose (133064) in fuel feed left line.
- Remove fuel pump relay. See «DME & FUEL PUMP RELAY LOCATION»(ref-10053-S25288169012000110700000) table. Connect jumper wire between relay base terminals No. 30 and 87. Read off fuel injection pressure on pressure gauge.
- If fuel pressure drops rapidly, seal return line (upper line) with Clamp (133010) and briefly operate fuel pump. If injection pressure in now stable, pressure regulator is defective. If injection pressure drops, check for leak in front of pressure regulator.
Fuel Pressure Check (Lack Of Power)
Run engine at idle and check fuel pressure. See FUEL PRESSURE REGULATOR. Disconnect vacuum hose from fuel pressure regulator, simulating wide open throttle. If fuel pressure does not increase 5.8-10.1 psi (.40-.71 kg/cm 2 ), replace vacuum hose and repeat test. If fuel pressure still does not increase, replace fuel pressure regulator.
Fuel Pressure Check (Hard Start)
- Run engine at idle then turn off. Note fuel pressure. Note fuel pressure again after 20-30 minutes. If fuel pressure decreases by greater than 7.2 psi (.5 kg/cm 2 ), turn engine on, wait for pressure to stabilize, then turn engine off and immediately clamp off intake line near pressure gauge with Clamp (133010). Note fuel pressure. Read fuel pressure again after 20-30 minutes.
- If fuel pressure drops by less than 7.2 psi (.5 kg/cm 2 ), check for fault in fuel supply lines, in-tank supply hose, or defective non-return valve in fuel pump. If fuel pressure again drops by more than 7.2 psi (.5 kg/cm 2 ), replace pressure regulator.
Fuel Volume
Disconnect fuel return line. Attach an extension hose. Place hose in Measuring Glass (133020). Remove fuel pump relay. Apply battery voltage to relay base terminals No. 30 and 87. (Scheme 76) Fuel volume should be about 2 qts. (2.0L) per minute.
Scheme 76
Fuel Injector
Individual fuel injector resistance should be 15-17 ohms. Injector group resistance should be 7.5-8.5 ohms for 4-cylinder engine and V8 (each bank) and 5-6 ohms for 6-cylinder engine.
IDLE SPEED CONTROL VALVE
See IDLE SPEED CONTROL VALVE LOCATION table. Idle speed control valve is either a 2-pin or 3-pin type. (Scheme 77)and (Scheme 78). See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS.
Scheme 77
Scheme 78
| Application | Location |
|---|---|
| All Models | At Left Front Of Engine, Near Dipstick |
IDLE SPEED CONTROL VALVE LOCATION
IGNITION SYSTEM
Note. For basic ignition checks, see BASIC TESTING article.
Fuel Tank Vent (Evaporation) Control Solenoid
See FUEL EVAPORATION CONTROL SOLENOID LOCATION table. See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS .
| Application | Location | |
|---|---|---|
| Z3 | On Right Side Of Left Footwell | |
| 3-Series | On Left Side Of Engine Compartment | |
| 5-Series | ||
| 6-Cylinder | Left Rear Side Of Engine Compartment | |
| V8 | Left Side Of Engine Compartment | |
| 7-Series | Left Side Of Engine Compartment | |
| 8-Series | Front Of Engine | |
FUEL EVAPORATION CONTROL SOLENOID LOCATION