Direct Ignition System (DIS)
- Ensure ignition is turned off before working on the ignition system. The engine will not start without a connected secondary circuit. When checking compression, remove Digital Motor Electronics (DME) master relay.
- Shielded capacitors may not be connected to terminal No. 1 of the ignition coil. Terminal No. 1 of the ignition coil may not be connected to ground or battery positive terminal, as this will damage ignition stages in DME control unit.
- DO NOT connect DVOM or test light to terminal No. 1 of ignition coil while engine is running. High tension (350 volts) is present at coil terminal No. 4, secondary ignition leads, spark plugs and ignition coil terminal No. 1 to DME control unit.
Note. For location of DME master and fuel pump relays, see DME & FUEL PUMP RELAY LOCATION table under FUEL SYSTEM PRESSURE RELEASE under FUEL SYSTEM .
FUEL SYSTEM
| WARNING | Always relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components. |
FUEL SYSTEM PRESSURE RELEASE
Fuel system pressure release procedure not available from manufacturer. It may be possible to remove fuel pump relay, start engine, and run engine until fuel pressure drops (engine stalls). See DME & FUEL PUMP RELAY LOCATION table.
| Application | Location |
|---|---|
| 325i, 325iC & 325is | (1) Behind Cover, Along Engine Compartment Firewall |
| 525i & 525iT | (2) Right Inner Fender Panel Of Engine Compartment |
| (1) First relay (viewed from left to right) after ground wire is fuel pump relay followed by Digital Motor Electronics (DME) master relay. (2) First relay (viewed from top to bottom) is Digital Motor Electronics (DME) master relay, followed by fuel pump relay and then oxygen sensor heater relay. | |
| (1) | First relay (viewed from left to right) after ground wire is fuel pump relay followed by Digital Motor Electronics (DME) master relay. |
| (2) | First relay (viewed from top to bottom) is Digital Motor Electronics (DME) master relay, followed by fuel pump relay and then oxygen sensor heater relay. |
DME & FUEL PUMP RELAY LOCATION
FUEL PUMP
Note. Removal & installation procedure on models not listed is not available from manufacturer.