Gilera Runner Purejet 2007, Workshop Manual, Page: 177 / 257

19. The system is capable of providing the correct fuel supply pressure.
N.B.
THE PRESSURE FIGURES SHOWN REFER TO A WARM ENGINE. WITH THE ENGINE COLD AND
AT IDLE THE PRESSURE FIGURES MAY BE LOWER BY 0.5 BAR, DUE TO LONGER INJECTION
CYCLES. REVVING UP WITH THE ENGINE HOTa OR JUST AFTER START UP, AIR BUBBLES
MAY BE FOUND IN THE RETURN DUCT TO THE TANK. THIS IS NORMAL, AS A RESULT OF THE
INJECTOR OPERATION IN THE PRESENCE OF PRESSURE PULSES.
20. Shut down the engine and check that pressures are maintained.
NO point 21 NO point 22 YES point 25
N.B.
WHEN THE SWITCH IS TURNED TO «OFF», THE PUMP AND INJECTOR STOP WORKING, AND
THE ENGINE CONTINUES TO RUN ON ITS MOMENTUM UNTIL IT STOPS. THIS CAUSES A SIG-
NIFICANT INCREASE IN THE AIR PRESSURE, WHICH IS NOT ACCOMPANIED BY ANY RISE IN
THE FUEL PRESSURE. ENSURE THAT PRESSURES REMAIN CONSTANT IN TIME.
21. Both pressures decrease rapidly in time and
the fuel settles at 2.5 BAR.
Check the sealing of the compressed air system.
22. The air pressure remains constant.
The fuel pressure decreases rapidly.
Bring the pressure back up into the system by
starting the engine.
Shut down the engine and, at the same time, close
the rubber hose on the injector mounting side, us-
ing flat-ended pliers.
Check that the fuel pressure remains constant.
NO point 23 YES point 24
Specific tooling
020616Y Fuel pressure control kit
23. The fuel pressure does not remain constant.
The one-way valve attached to the pump does not seal properly.
Replace the fuel pump.
GO TO point 20
24. The fuel pressure remains constant.
If the seal failure is not followed by noticeable engine malfunctions, it may be due to a leak toward the
fuel return circuit, caused by the pressure regulator or its O-Ring.
Any pressure loss not observed from the outside may lead to operational faults caused by an exces-
sively rich fuel mixture.
Replace the injector mounting assembly together with the pressure regulator.
GO TO point 20
25. The air and fuel pressures remain constant with time.
All system components guarantee a good seal.
Runner Purejet
pure jet injection
INJ PJ - 177