Kia Optima DL3 Quiz
Engine Control System/Fuel System

Fuel Delivery System

In this manual: Engine Control System/Fuel System
General Information — 8Advanced Driver Assistance System (ADAS) — 21Maintenance — 27Engine Mechanical System — 45Engine Electrical System — 11Emission Control System — 11Engine Control System/Fuel System — 25Automatic Transmission — 20Drive Shaft and Axle — 7Suspension System — 22Steering — 7Restraints — 11Brake System — 22Body (Interior and Exterior) — 116Body Electrical System — 90Heating, Ventilation, and Air Conditioning — 32
12steps
~72min
4/5difficulty
Done 0 of 12

Fuel Pressure Inspection

Fuel Pressure Inspection

  1. Release the residual pressure in the fuel line.

    (Refer to Fuel Supply System - "Relieve Fuel Pressure")

  2. Install the Special Service Tool (SST).

    1. Disconnect the quick-connect coupling of the fuel feed tube (A).

    2. Install the special service tool for measuring fuel pressure between the fuel feed hose and the fuel feed pipe (refer to the illustration below).

  3. With the ignition switched ON, inspect for fuel leaks at the connections between the fuel feed hose, pipe and SST components.

  4. Measure the fuel pressure.

    1. Start the engine and measure fuel pressure at idle.

      Fuel pressure: 330–370 kPa (3.36–3.77 kgf/cm², 47.8–53.6 psi)

      Fuel
      Pressure      		 Cause Related Part
      Too low Clogged fuel filter Fuel filter
      Fuel leakage Fuel Pressure Regulator
      Too high Fuel pressure regulator valve stuck Fuel Pressure Regulator

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

      Specification: The fuel pressure gauge reading should be maintained for approximately 5 minutes after the engine is stopped.

      Fuel Pressure
      (After Engine Stop)      		 Cause Related
      Part
      Fuel pressure drops slowly Injector leakage Injector
      Fuel pressure drops immediately Fuel pump check valve stuck open Fuel pump

    3. Turn the ignition off.

  5. Release the residual pressure in the fuel line.

    (Refer to Fuel Supply System - "Relieve Fuel Pressure")

  6. Remove the SST from the fuel feed tube and the discharge tube.

  7. Install the fuel feed tube to the discharge line.

Release Residual Fuel Line Pressure

Release Fuel Line Residual Pressure

  1. After disconnecting the negative (-) battery cable, remove the fuel pump fuse (A).

  2. Connect the negative battery cable.

  3. Start the engine and let it idle. Turn the ignition switch OFF after the engine stops by itself.

  4. After connecting the negative (-) battery cable, install the fuel pump fuse.

  5. Clear the Diagnostic Trouble Code (DTC) related to the fuel pump fuse using the KDS.

Test yourself

A quick Kia Optima DL3 quiz: every answer comes with an explanation and a link to the manual page.