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Home >> Mazda >> 2004 >> RX-8 1.3 3 >> Repair and Diagnosis >> External Pages >> Different car >> Section 55 (Engine Controls [Basic Diagnostic Procedures]) >> Fuel System >> Fuel Pressure (B2300, B3000, B4000 & Tribute) >> Fuel Line Pressure/Fuel Pressure Hold Inspection

Fuel Line Pressure/Fuel Pressure Hold Inspection

WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2003 Mazda Tribute, 2003 Mazda Protege5, 2003 Mazda Protege, 2003 Mazda MX-5 Miata, and 2003 Mazda MPV. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Fuel pump will only operate for about 8 seconds when Output Test Mode is selected and activated.

  1. Check Fuel Pressure

    Release fuel pressure. See FUEL PRESSURE RELEASE . Install Fuel Pressure Gauge (49-UN01-010). Turn ignition on, engine off. Connect scan tool to DLC. Select DIAGNOSTIC DATA LINK. Select PCM. Select ACTIVE COMMAND MODE. Select OUTPUT TEST MODE and FUEL PUMP PID. Press MODE to change to ALL ON MODE. Press START, to run fuel pump and observe fuel pressure. For fuel pressure specifications, see FUEL SYSTEM in SERVICE & ADJUSTMENT SPECIFICATIONS article. If fuel pressure is as specified, go to next step. If fuel pressure reading is zero or low, check fuel pump. See FUEL PUMP OPERATION . If fuel pump is okay, go to next step. If fuel pressure is high, go to step  3.

  2. Check Fuel Supply Line For Restriction

    Release fuel pressure. Disconnect fuel supply line at fuel rail. Disconnect fuel supply line at fuel pump. Check for restriction in fuel supply line (blockage, kinked or pinched). Using regulated air pressure of 3-5 psi (21-34 kPa), blow air through fuel supply line. If air flows freely, replace fuel pump. If air does not flow freely, repair restriction as necessary. Restore vehicle back to original condition and recheck fuel system.

  3. Check Fuel Pressure After One Minute

    Turn fuel pump relay off and observe fuel pressure. Wait one minute. If fuel pressure reading is within 5 psi of previous pressure reading, fuel pressure hold inspection is okay. If fuel pressure drops more than 5 psi, inspect fuel injectors for leaks. Refer to FUEL CONTROL under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - B2300, B3000, B4000 & TRIBUTE article.
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