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Fuel System Pressure Test

NOTE: Before testing fuel pressure, check all fuel delivery and return lines for leaks.
  1. Ensure battery is fully charged. Turn ignition off. Place container or shop towel under cold start injector. Slowly loosen cold start injector union bolt to relieve fuel pressure. Remove union bolt and 2 gaskets.
  2. Install fuel pressure gauge to the cold start injector delivery pipe. See Fig 1. Wipe off excess gas. See Fig 1.
  3. On all models, install jumper wire between engine check connector "FP" and "B" pins. See Figure. See ENGINE CHECK CONNECTOR LOCATION table.
  4. On all models, turn ignition on, with engine off. Measure fuel pressure. Fuel pressure should be same as unregulated pressure. See appropriate FUEL PUMP PERFORMANCE table.
  5. If fuel pressure is high, replace the fuel pressure regulator. If fuel pressure is low, check the following:
    • Fuel hoses and connections.
    • Fuel pump.
    • Fuel filter.
    • Fuel pressure regulator.
  6. Remove jumper wire installed in step 3). Start engine and run for 2 minutes. Disconnect vacuum sensing hose from fuel pressure regulator and plug hose end. Fuel pressure regulator is mounted on fuel rail.
    NOTE: Land Cruiser, and Supra Turbo it is necessary to allow engine to idle for 2 minutes to stabilize fuel pressure. These models are equipped with a fuel pressure-up system which temporarily increases fuel pressure after a hot start.
  7. Measure unregulated fuel pressure at idle speed. See appropriate FUEL PUMP PERFORMANCE table.
  8. With engine still idling, reconnect fuel pressure regulator sensing hose. Measure regulated pressure at idle.
  9. If regulated pressure was not as specified, check vacuum sensing hose and fuel pressure regulator. On models so equipped, check fuel pressure-up system. See I - EFI SYS/COMP TESTS.
  10. Stop engine. Note fuel pressure. Leave fuel pressure gauge attached to engine for at least 5 minutes.
  11. Residual fuel pressure after 5 minutes should be at least 21 psi (1.5 kg/cm2 ). If pressure is not as specified check for leaking injectors, fuel pressure regulator or bad check valve in fuel pump.
  12. Relieve fuel system pressure. Remove fuel pressure gauge. Install cold start injector. Run engine and check for fuel leaks.
NOTE: For more information on checking fuel injectors and other fuel sub-systems, see I - EFI SYS/COMP TESTS article in this section.
Fig 1: Typical Fuel Pressure Gauge Connections
G118546Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
FUEL PUMP PERFORMANCE

Application Unregulated (1) Pressure psi (kg/cm2 ) Regulated (2) Pressure psi (kg/cm2 )
Cressida 38-44 (2.7-3.1) 33-37 (2.3-2.6)
Land Cruiser 37-46 (2.6-3.2) 33-37 (2.3-2.6)
Supra
Turbo 33-40 (2.3-2.8) 23-30 (1.6-2.1)
Non-Turbo 38-44 (2.7-3.1) 33-37 (2.3-2.6)
(1) With pressure regulator vacuum hose disconnected and plugged.
(2) With vacuum hose connected to pressure regulator.
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