Fuel Pressure-Up System Test (Turbo)

1. Ensure coolant temperature sensor, air temperature sensor (in airflow meter) and circuits are operating correctly. See specific SENSOR or SWITCHES testing in this article. Supra fuel pressure-up vacuum switching valve is located at the lower side of the intake manifold runners.
2. Fuel pressure-up system is controlled by ECU through a vacuum switching valve. The vacuum switching valve is fed current through the EFI main relay when the ignition is turned on. ECU controls the ground circuit. ECU will activate vacuum switching valve for 90-180 seconds when restarting engine at normal operating temperature. To test, See Fig 1.

Fig 1: Testing Fuel Pressure-Up Vacuum Switching Valve (Turbo)

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