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Home >> Mazda >> 1994 >> 929 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing >> Fuel System >> Fuel Pressure (Fuel Injection) >> Fuel Pressure
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Fuel Pressure

  1. Disconnect circuit opening relay. See CIRCUIT OPENING RELAY LOCATIONS table.
  2. To bleed down fuel in system, start engine (if possible) and allow to die. Connect pressure gauge to fuel line at fuel filter. Reconnect circuit opening relay.
  3. Turn ignition on. Jump test connector terminals Fp and ground. If pump does not run, check fuel pump circuit and circuit opening relay.
  4. If possible, start engine. Check fuel pressure with vacuum connected to and disconnected from pressure regulator. See REGULATED FUEL PRESSURE  table. Turn engine off and disconnect jumper wire at fuel pump check connector. Wait 10 minutes and ensure residual pressure is at least 21 psi (1.5 kg/cm2 ).
  5. Operate fuel pump by jumpering fuel pump test connector. Check fuel pump performance. Pinch hose between pressure gauge and fuel filter. DO NOT hold longer than necessary to check pressure. See FUEL PUMP PERFORMANCE  table. If pump does not meet specifications, check fuel pump circuits, fuel pump, fuel tank, fuel filter and repair or replace as necessary.
FUEL PUMP PERFORMANCE

Application Pressure
929 (1) 64-92 psi (4.5-6.5 kg/cm2 )
(1) Minimum volume in 30 seconds is 1.0 pint (.47L).
REGULATED FUEL PRESSURE

Application At Idle W/ Vacuum: psi (kg/cm2 ) At Idle W/O Vacuum: psi (kg/cm2 )
929 31-38 (2.2-2.7) 38-46 (2.7-3.2)
NOTE: Fuel pump control unit terminal identification is not available.