Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSINFINITI2002G20 L4-2.0L (SR20DE)REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTTUNE-UP AND ENGINE PERFORMANCE CHECKSCOMPRESSION CHECKTESTING AND INSPECTION
2002 Infiniti G20 L4-2.0L (SR20DE)
Compression Check: Testing and Inspection
2002 Infiniti G20 L4-2.0L (SR20DE)SECTION Testing and Inspection
MEASUREMENT OF COMPRESSION PRESSURE
1. Warm up engine.
2. Turn ignition switch OFF.
3. Release fuel pressure. Refer to Powertrain Management; Fuel Delivery and Air Induction.
4. Remove all spark plugs.
5. Disconnect distributor coil connector.
6. Attach a compression tester to No. 1 cylinder.
7. Depress accelerator pedal fully to keep throttle valve wide open.
8. Crank engine and record highest gauge indication.
9. Repeat the measurement on each cylinder.
Always use a fully-charged battery to obtain specified engine speed.
Compression pressure:
Standard: ..........1,275 kPa (13.0 kg/cm2, 185 psi)/300 rpm
Minimum: .............1,079 kPa (11.0 kg/cm2, 156 psi)/300 rpm
Difference limit between cylinders: 9.......8 kPa (1.0 kg/cm2, 14 psi)/300 rpm
10. If compression in one or more cylinders is low:
a. Pour a small amount of engine oil into cylinders through spark plug holes.
b. Retest compression.
If adding oil helps compression, piston rings may be worn or damaged. If so, replace piston rings after checking piston.
If pressure stays low, a valve may be sticking or seating improperly. Inspect and repair valve and valve seat. If valve or valve seat is damaged excessively, replace them.
If compression stays low in two cylinders that are next to each other:
I. The cylinder head gasket may be leaking, or
II. Both cylinders may have valve component damage. Inspect and repair as necessary.
1. Warm up engine.
2. Turn ignition switch OFF.
3. Release fuel pressure. Refer to Powertrain Management; Fuel Delivery and Air Induction.
4. Remove all spark plugs.
5. Disconnect distributor coil connector.
6. Attach a compression tester to No. 1 cylinder.
7. Depress accelerator pedal fully to keep throttle valve wide open.
8. Crank engine and record highest gauge indication.
9. Repeat the measurement on each cylinder.
Always use a fully-charged battery to obtain specified engine speed.
Compression pressure:
Standard: ..........1,275 kPa (13.0 kg/cm2, 185 psi)/300 rpm
Minimum: .............1,079 kPa (11.0 kg/cm2, 156 psi)/300 rpm
Difference limit between cylinders: 9.......8 kPa (1.0 kg/cm2, 14 psi)/300 rpm
10. If compression in one or more cylinders is low:
a. Pour a small amount of engine oil into cylinders through spark plug holes.
b. Retest compression.
If adding oil helps compression, piston rings may be worn or damaged. If so, replace piston rings after checking piston.
If pressure stays low, a valve may be sticking or seating improperly. Inspect and repair valve and valve seat. If valve or valve seat is damaged excessively, replace them.
If compression stays low in two cylinders that are next to each other:
I. The cylinder head gasket may be leaking, or
II. Both cylinders may have valve component damage. Inspect and repair as necessary.
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.