Fuel Pressure Test

Release the residual pressure in fuel line (Refer to "Release Residual Pressure in Fuel Line ").
CAUTION: When removing the fuel pump relay, a Diagnostic Trouble Code (DTC) may occur. Delete the code with the GDS after completion of "Release Residual Pressure in Fuel Line" work.
Install the Special Service Tool (SST).
1. Disconnect the fuel feed tube from the high pressure fuel pump.
  CAUTION: There may be some residual pressure even after "Release Residual Pressure in Fuel Line" work, so cover the hose connection with a shop towel to prevent residual fuel from spilling out before disconnecting any fuel connection.
2. Install the special service tool for measuring the fuel pressure in between the fuel feed tube and the high pressure fuel pump .
  
  Fig 1: Installing Special Service Tool For Measuring Fuel Pressure In Between Fuel Feed Tube And High Pressure Fuel Pump
  Courtesy of HYUNDAI MOTOR CO.
Inspect fuel leakage on connections among the fuel feed tube, the high pressure fuel pump, and the SST components with IG ON.

Measure Fuel Pressure.

Start the engine and measure the fuel pressure at idle.
Fuel Pressure:

579 kPa (5.9 kgf/cm, 83.9 psi)

Stop the engine, and then check for the change in the fuel pressure gauge reading.

NOTE: If the fuel pressure differs from the standard value, repair or replace the related part .

Fuel Pressure	Cause	Related Part
Too Low	Fuel filter clogged	Fuel Filter
Too Low	Fuel leakage	Fuel Pressure Regulator
Too High	Fuel pressure regulator stuck	Fuel Pressure Regulator

Release the residual pressure in fuel line (Refer to "Release Residual Pressure in Fuel Line ").
CAUTION: When removing the fuel pump relay, a Diagnostic Trouble Code (DTC) may occur. Delete the code with the GDS after completion of "Release Residual Pressure in Fuel Line" work.
Test End
1. Remove the Special Service Tool (SST) from the fuel feed tube and the high pressure fuel pump.
2. Connect the fuel feed tube and the high pressure fuel pump.