Fuel System Inspection

■ Fuel Line Pressure Inspection 

1. Check the fuel for excessive water, alcohol, or other contaminants. Replace contaminated fuel as necessary.
2. Install a fuel pressure gage
3. Inspect fuel pressure with normal idle status

   Specification:  338~348kPa(3.45~3.55kg/cm² )

4. Is fuel pressure within the specified value?

   YES 

   • Go to next step as below.

   NO 

   • Inspect the suspected area. Refer to table as below. Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.

   Condition	Possible Cause	Suspected Area
   Fuel Pressure too low	Clogged fuel filter	Fuel filter
   	Fuel leak on the fuel-pressure regulator that is assembled on fuel pump	Fuel Pump (Fuel Pressure Regulator)
   Fuel Pressure too high	Sticking fuel pressure regulator	Fuel Pump (Fuel Pressure Regulator)

■ Fuel Pressure Hold Inspection 

1. Stop the engine and check for a change in the fuel pressure gauge reading.

   Specification:  After engine stops, the gauge reading should hold for minimum 5 minutes

2. Is fuel pressure within the specified value?

   YES 

   • Go to next step as below.

   NO 

   • Inspect the suspected area. Refer to table as below. Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.

   Condition	Possible Cause	Suspected Area
   Fuel pressure drops slowly	Injector leak	Injector
   Fuel pressure drops immediately	Stuck open check valve of the fuel pump	Fuel pump

Engine Compression Test 

1. Warm up the engine to normal operating temperature. Verify the battery must be at or near full charge.
2. With ignition "OFF", disconnect the ignition coil connectors and the spark plug cables.
3. Install compression pressure gauge to the spark plug hole.
4. With wide open throttle by hand, cranking the engine and record the compression readings from all of the cylinders.

   Specification: 

   Compression pressure: 1, 283kPa (13.0kgf/cm² , 185psi)

   Minimum pressure: 1, 135kPa (11.5kgf/cm² , 164psi)

   Difference between each cylinder: 100kPa (1.0kgf/cm² , 15psi) or less

5. Is compression pressure within the specified value?

   YES 

   • Verify if the engine has excessive coolant consumption. If yes, check for damaged inlet water passage, engine block, cylinder head or head gasket. Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.

   NO 

   • If the cylinder compression in 1 or more cylinders is low, pour a small amount of engine oil into the cylinder through the spark plug hole and repeat compression test for cylinders with low compression pressure.
     • If adding oil helps the compression, it is likely that the piston rings and/or cylinder bore are worn or damaged.
     • If pressure stays low, a valve may be sticking or seating is improper, or there may be leakage past the gasket.

     Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.