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Fuel Pressure (Fuel System): Sienna

  1. Ensure battery is fully charged. Release fuel pressure by loosening union bolt at top of fuel filter. See FUEL PRESSURE RELEASE  under FUEL SYSTEM.
  2. Note location of fuel pressure gauge installation on fuel filter. See Fig 1. Remove union bolt and gaskets from fuel filter. Install fuel pressure gauge from Fuel Pressure Gauge Set (SST 09268-45012) with gaskets and union bolt on fuel filter. See Fig 1. Tighten union bolt to 21 ft. lbs. (29 N.m).
  3. Reconnect negative battery cable. Connect scan tool to data link connector No. 3. See Figure-7. Turn ignition on. DO NOT start engine.
  4. Turn scan tool on. Select ACTIVE TEST MODE on scan tool. Using scan tool manufacturer's instructions, activate fuel pump and note fuel pressure. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm2 ).
    NOTE: Fuel pump may also be activated by connecting battery voltage to specified terminals on fuel pump. See Figure.
  5. If fuel pressure is within specification, go to next step. If fuel pressure exceeds specification, replace fuel pressure regulator mounted on fuel pump in the fuel tank. See REMOVE/INSTALL/OVERHAUL article. If fuel pressure is less than specified, check for leaking fuel hoses or connections, restricted fuel filter, defective fuel pump or defective fuel pressure regulator.
  6. Remove scan tool from data link connector No. 3. Start engine and note fuel pressure with engine idling. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm2 ).
  7. Shut engine off and note fuel pressure. Fuel pressure should remain at least 21 psi (1.5 kg/cm2 ) for a minimum of 5 minutes. If fuel pressure is within specification and holds as specified, go to next step. If fuel pressure is not within specification or does not hold as specified, check for defective fuel pump, fuel injector or fuel pressure regulator.
  8. Release fuel pressure. Disconnect negative battery cable. Remove fuel pressure gauge. Using NEW gaskets, reinstall fuel inlet hose on fuel filter. Tighten union bolt to 21 ft. lbs. (29 N.m).
  9. Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump.
Fig 1: Installing Fuel Pressure Gauge (Sienna)
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