System Inspection

■ Check power balance

NOTE: This test is to find out that possible cause of the problem is error in specific cylinder or fuel system.
Warm up the engine to normal operating temperature for getting a reliable result.

CAUTION: Pull up the parking brake and shift the gear into "P" position before the test.

Warm up the engine and maintain idle state.
Using GDS, select engine rpm parameter in sensor display window and injector in actuation test window together as follow figure.
Recode engine rpm at a time when injector stops working after press "Start" button in actuation test window.
Repeat above test on all cylinders.
Specification: The deviation of the engine rpm between each cylinder should be same

Fig 1: Screen Display - Current Data
Courtesy of HYUNDAI MOTOR AMERICA

Fig 2: Screen Display - Actuation Test
Courtesy of HYUNDAI MOTOR AMERICA

Fig 3: Screen Display - Current Data
Courtesy of HYUNDAI MOTOR AMERICA

Fig 4: Screen Display - Actuation Test
Courtesy of HYUNDAI MOTOR AMERICA
Does each cylinder show the similar engine rpm?
YES
- Go to next procedure.
NO
- If there is no hang in engine rpm when injector stops working, it might be caused by fuel or ignition system error.
- If engine rpm drops over 200 rpm in power balance test, check engine internal damage by testing compression pressure with pressure gauge.

■ Check Air Leakage

Visually/physically inspect the air leakage in intake/exhaust system as following items,
- Vacuum hoses for splits, kinks and improper connections.
- Throttle body gasket.
- Gasket between intake manifold and cylinder head.
- Seals between intake manifold and fuel injectors.
Has a problem been found in any of the above areas?
YES
- Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
NO
- Go to next procedure.
Check for air leakage in purge system.

Remove vacuum hose between canister purge valve and intake manifold.
Apply approx. 15 inch HG vacuum to removed hose after blocking the one side.
Is vacuum maintained?
YES
- Go to next procedure.
NO
- Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.

■ Check fuel pressure

NOTE:

Be cautious that Fuel is explosive and an empty fuel tank can still contain explosive gases. When working on fuel system make sure to supply adequate ventilation to the work area. Do not smoke, and keep sparks and open flames away.
The fuel system remains under pressure when the engine is not running. Release fuel system pressure before disconnecting any fuel line to reduce the chance of personal injury or fire damage to vehicle components.

IG "OFF" and disconnect Fuel Pump Relay in Junction Box.
Start-up and wait until it stops itself.
IG "OFF" and connect Fuel Pump Relay.
Install the fuel pressure gauge to the delivery pipe with the fuel pressure gauge adaptor.
Activate the fuel pump, and with fuel pressure applied, check that there is no fuel leakage from the pressure gauge or connection part.
Measure the fuel pressure at idle.
Specification: 490 ~ 530 kPa (5.0 ~ 5.4 kg/cm² , 71.0 ~ 76.7 psi)
Is the measured fuel pressure within specifications?
YES
- Go to next procedure.
NO
- Repair or replace according to the below table. And then, go to "VERIFICATION OF VEHICLE REPAIR " procedure.

Condition	Possible Cause
Fuel Pressure is too low	Fuel filter, fuel pressure regulator, in-tank fuel hose or the fuel pump
Fuel Pressure is too high	Fuel pressure regulator, hose or pipe

■ Check Spark Plug

Check spark plug and ignition coil.
1. Visually/physically inspect the following items:
  - Damaged insulation, Worn electrodes, Oil or fuel fouled, Loose terminals and cracks.
  - Loose connection of electrical wires.
  - Poor connection.
2. Measure resistance of spark plug component.
  Specification: 3 ~ 7.5 kΩ
3. Measure resistance of primary and secondary ignition coil.
  Specification: Primary ignition coil: 0.62 ± 10% (20°C(68°F)), Secondary ignition coil: 7.0k ± 15% (20°C(68°F))
4. Has a problem been found?
  YES
  - Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
  NO
  - Go to next procedure.
Check Spark Plug.

Visually/physically inspect the following items:
- Damaged insulation, Worn electrodes, Oil or fuel fouled, Loose terminals and cracks
- Check for plug gap: 1.0 ~ 1.1 mm
Has a problem been found?
YES
- Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
NO
- Go to next procedure.