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Page Hits: 4688701
NOTICE No: MT000000148
MODEL: Mazda MPV YEAR: 2000-2002
SUBJECT: Hard start hot or cold - fuel pressure regulator
APPLICABLE MODELS: 99-02 Protege, 93-95 RX-7, 98-02 626, 00-02 MPV, 99-02 Miata, 95-02 Millenia

If the vehicle cranks but does not start or takes excessive time to start, it may be caused by the fuel pressure regulator/fuel system. Follow the inspection procedure below to determine what component of the fuel system may be at fault.

Check fuel pressure (fuel pressure regulator may not maintain pressure).

The only sure way of checking, is to clamp off hoses with a pair of smooth vise grips in the following order.

  1. Check fuel pressure when engine is in a no start condition. If pressure is low and increases only after cycling the ignition key on and off two or three times, the pressure regulator could be leaking. 
  2. Clamp off supply hose from tank (high pressure from filter). If pressure is now maintained, the pump check valve is leaking. If pressure still drops, see the next step.
  3. Clamp off return hose from fuel rail to tank after running engine again to normalize pressures. If pressure is now maintained, pressure regulator was leaking.
  4. With both clamps on and pressure drops, leaky fuel injectors are at fault. There is no other way for fuel to escape.

If the pump operates and the fuel pressure is zero, then either the check valve or safety valve is leaking. After replacing the fuel pump, recheck the fuel pressure. If restriction is not corrected damage could occur to the new pump.

The information and instructions in this notice are intended for use by skilled technicians. Mazda technicians utilize the proper tools/equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by "do-it-yourselfers." Consumers should not assume this notice applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies, consumers should contact their nearest authorized Mazda dealership.
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