Fuel Pressure Test

Reduce the internal pressure of the fuel lines and hoses:
- Disconnect the fuel pump harness connector
- Start the engine and after it stalls, turn the ignition switch to the OFF position
- Disconnect the battery negative (-) terminal
- Connect the fuel pump harness connector
Fig 1: View Of Fuel Pump
Courtesy of HYUNDAI MOTOR CO.
Remove the bolt connecting the fuel line to the fuel delivery pipe.

Fig 2: View Of Fuel Deliver Pipe
Courtesy of HYUNDAI MOTOR CO.

CAUTION: Cover the hose connection with a shop towel to prevent splashing of fuel caused by residual pressure in the fuel line.
Using the fuel pressure gauge adapter, install the fuel pressure gauge to the fuel pressure gauge adaptor. Tighten the bolt to the specified torque.
Fuel pressure gauge to fuel delivery pipe:

25~35 Nm (250~350 kg.cm, 18~26 lb.ft)

Fig 3: Identifying Fuel Pressure Gauge Adapter
Courtesy of HYUNDAI MOTOR CO.
Connect the battery's negative (-) terminal.
Apply battery voltage to the terminal for the pump drive and activate the fuel pump. With fuel pressure applied, check that there is no fuel leakage from the pressure gauge or connection part.
Start and run the engine at curb idle speed.
Disconnect the vacuum hose from the pressure regulator, and plug the hose end. Measure the fuel pressure at idle.
Standard value:

320~340 kPa (3.26~3.47 kg/cm² , 46~49 psi)

Fig 4: Identifying Plugged Vacuum Hose
Courtesy of HYUNDAI MOTOR CO.
Measure the fuel pressure when the vacuum hose is connected to the pressure regulator.
Standard value:

Approx. 255 kPa (2.57 kg/cm² , 37 psi)
If the results of the measurements made in steps (7) and (8) are not within the standard value, use the table below to determine the probable cause, and make the necessary repairs.

Fig 5: Identifying Fuel Pressure Gauge Adapter
Courtesy of HYUNDAI MOTOR CO.

Fig 6: Fuel Pressure Symptom Chart
Courtesy of HYUNDAI MOTOR CO.
Stop the engine and check for a change in the fuel pressure gauge reading, which should hold for approximately 5 minutes. If the gauge indication drops, observe the rate at which it drops. Determine and remove the causes according to the following table.

Fig 7: Fuel Pressure Bleed Off Symptom Chart
Courtesy of HYUNDAI MOTOR CO.
Reduce the pressure in the fuel line.
Disconnect the hose and the gauge.
CAUTION: Cover the hose connection with a shop towel to prevent splashing of fuel caused by fuel residual pressure in the fuel line.
Replace the O-ring at the end of the hose.
Connect the fuel hose to the delivery pipe and tighten to the specified torque.
Check for fuel leakage.
- Apply battery voltage to the fuel pump drive terminal to operate the fuel pump.
- With pressure, check the fuel line for leaks.
Fig 8: Applying Battery Voltage To Fuel Pump Drive Connector
Courtesy of HYUNDAI MOTOR CO.