Fuel
pump not running.
|
| Check fuse 11 (7.5A). OK ? |
NO
|
Replace fuse. If no power to fuse, check
fuel pump relay. |
YES
|
|
|
| Connect volt meter to both wires of pump. Crank engine.
Battery voltage present ? |
NO
|
Check resistance from brown wire to ground. Approx. 0 Ohms ? |
NO
|
Repair wire |
YES
|
|
YES
|
|
| Replace pump |
Check green/violet wire resistance from pump to pin 87a on
fuel pump relay connector, with relay removed. Approx. 0 Ohms ? |
NO
|
Repair wire |
|
Fuel pump running only during
start
|
| Remove fuel pump relay, check voltage between terminal 30 and
ground. Battery voltage ? |
NO
|
Check and repair 1.5mm red wire from relay to
battery junction block or battery in engine bay.
NOTE : Some models take power from the main relay. In these cars, check
operation of main relay |
YES
|
| Check voltage from pin 86 to ground with ignition on. Battery
voltage ? |
NO
|
Check operation of main relay. Check and
repair the 0.5mm red or red/white wire from pin 87 of main relay |
YES
|
| Check voltage between pin 85 to battery power. Crank engine.
Battery voltage ? |
NO
|
Check appropriate wiring diagram for ground
source. M10 uses starter to ground relay, all others use the DME to trigger relay. |
YES
|
| M10 only, others skip this step : Check speed signal wire
resistance between pin 1 of fuel pump relay and ground. Approx. 0 Ohms ? |
NO
|
Check and repair 1.5mm black wire from pin 1 to
terminal 1 on coil. |
YES
|
| Replace fuel pump relay |
|
Fuel pressure low or high
|
| Check pressure by installing fuel pressure gauge inline on
fuel feed hose, fuel feed hose does NOT go to fuel pressure regulator. |
LOW
|
Check or replace fuel filter (low pressure), check for
obstructions or damage to fuel lines. OK ? |
NO
|
Repair or replace faulty component. |
| Note : Fuel pump works at approximately 100psi. It
is highly unlikely that a running pump will not be able to deliver specified fuel
pressure. |
YES
|
| |
Replace fuel pressure regulator. |
