Mazda Trucks 1987-1993 Repair Guide

Relieving Fuel System Pressure

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Fuel lines on fuel injected vehicles will remain pressurized after the engine is shut off. This residual pressure must be relieved before any fuel lines or components are disconnected.

Pickup and MPV

See Figures 1 through 6

  1. Start the engine.
  2.  



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Fig. Fig. 1: Disconnect the circuit opening relay connector-Pickups



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Fig. Fig. 2: Disconnect the volume airflow meter connector-MPV with 3.0L engine



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Fig. Fig. 3: Disconnect the fuel pump connector-MPV with 2.6L engine

  1. Disconnect the circuit opening relay connector, volume airflow meter connector or fuel pump connector.
  2.  
  3. After the engine stalls, turn OFF the ignition switch.
  4.  
  5. Reconnect the electrical connector.
  6.  



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Fig. Fig. 4: Connect the terminals of the yellow 2-pin test connector with a jumper wire-Pickups



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Fig. Fig. 5: Connect the terminals of the yellow 2-pin test connector with a jumper wire-MPV with 3.0L engine



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Fig. Fig. 6: Connect the terminals of the yellow 2-pin test connector with a jumper wire-MPV with 2.6L engine

After releasing fuel system pressure, the system must be primed before starting the engine to avoid excessive cranking. To prime the system, connect the terminals of the yellow 2-pin test connector with a jumper wire and turn the ignition switch ON for approximately 10 seconds. Check for fuel leaks, then turn the ignition switch OFF and remove the jumper wire.

Navajo

See Figures 7 and 8



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Fig. Fig. 7: The fuel pressure relief valve (A) is located on the fuel supply manifold



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Fig. Fig. 8: Fuel pressure can be checked and/or released using an inexpensive pressure/vacuum gauge

  1. Disconnect the negative battery cable and remove the fuel filler cap.
  2.  
  3. Remove the cap from the pressure relief valve on the fuel supply manifold. Install pressure gauge 49 UN01 010 or equivalent, to the pressure relief valve.
  4.  
  5. Direct the gauge drain hose into a suitable container and depress the pressure relief button.
  6.  
  7. Remove the gauge and replace the cap on the pressure relief valve.
  8.  

As an alternate method, disconnect the inertia switch and crank the engine for 15-20 seconds until the pressure is relieved.

 
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