Fuel Pressure Test (Low Pressure System)

Release the residual pressure in fuel line.
(Refer to the Fuel Delivery System - Inspection - "RELEASE RESIDUAL PRESSURE IN FUEL LINE ".)

CAUTION: When removing the fuel pump fuse, a Diagnostic Trouble Code (DTC) may occur. Delete the code with the KDS after completion of "Release Residual Pressure in Fuel Line" work.
Install the Special Service Tool (SST).
1. Disconnect the fuel feed tube from the delivery pipe.
  CAUTION: There may be some residual pressure even after completing to "Release Residual Pressure in Fuel Line", 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 fuel delivery pipe (Refer to the Fig 1 below).
  - For 09353-02100
    
    Fig 1: Install Special Service Tool (09353-02100)
    Courtesy of KIA MOTORS AMERICA, INC.
  - For 0K353-D4100
  Fig 2: Install Special Service Tool (0K353-D4100)
  Courtesy of KIA MOTORS AMERICA, INC.
Inspect fuel leakage on connections among the fuel feed tube, the delivery pipe, and the SST components with ignition "ON".

Measure Fuel Pressure.

Start the engine and measure the fuel pressure at idle.

Fuel Pressure : Over 290 kPa (Over 2.9 bar, Over 2.95 kgf/cm² , Over 42.06 psi)

NOTE: If the fuel pressure does not satisfy the specification, repair or replace the related part. (Refer to the table below.)

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

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

Standard Value : The gauge reading should hold for about 5 minutes after the engine stops

NOTE: If the gauge reading could not be held, repair or replace the related part. (Refer to the table below.)

Fuel Pressure (After Engine Stops)	Cause	Related Part
Fuel Pressure Drops Slowly	Leakage on injector	Injector
Fuel Pressure Drops Immediately	Check valve of fuel pump stuck open	Fuel Pump

Release the residual pressure in fuel line.
(Refer to the Fuel Delivery System - "RELEASE RESIDUAL PRESSURE IN FUEL LINE ".)

CAUTION: When removing the fuel pump fuse, a Diagnostic Trouble Code (DTC) may occur. Delete the code with the KDS after completion of "Release Residual Pressure in Fuel Line" work.
Finish test.
1. Remove the Special Service Tool (SST) from the low pressure fuel feed tube and the low pressure inlet of high pressure fuel pump.
2. Connect the low pressure fuel feed tube and the low pressure inlet of high pressure fuel pump.