Compression Pressure Inspection
Note. If the there is lack of power, excessive oil consumption or poor fuel economy, measure the compression pressure.
Scheme 14
Scheme 15
Scheme 16
- Warm up and stop engine. Allow the engine to warm up to normal operating temperature.
- Disconnect the injector extension connector (A) and ignition coil connectors (B).
- Remove ignition coils (A).
- Remove spark plugs. Using a 16 mm plug wrench, remove the 4 spark plugs.
- Check cylinder compression pressure. Insert a compression gauge into the spark plug hole. Fully open the throttle. While cranking the engine, measure the compression pressure. NOTE: Always use a fully charged battery to obtain engine speed of 200 RPM or more. Repeat steps 1 through 3 for each cylinder. NOTE: This measurement must be done in as short a time as possible. Compression pressure: 1, 324 kPa (13.5kgf/cm 2 , 192 psi) / 200 ~ 250 RPM Minimum pressure: 1, 177 kPa (12.0kgf/cm 2 , 171 psi) Difference between each cylinder: 100 kPa (1.0kgf/cm 2 , 15 psi) or less 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 steps 1 through 3 for cylinders with low compression. 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.
- Reinstall spark plugs.
- Install ignition coils.
- Connect the injector extension connector and ignition coil connectors.
- Some DTC's may exist after the inspection test and may need to be manually cleared with GDS.
Troubleshooting
| Symptom | Suspect area | Remedy |
|---|---|---|
| Engine misfire with abnormal internal lower engine noises. | Worn crankshaft bearings Loose or out of specification engine flywheel | Replace the crankshaft and bearings as required. Repair or replace the flywheel as required. |
| Worn piston rings (Oil consumption may or may not cause the engine to misfire.) | Inspect the cylinder for a loss of compression. Repair or replace as required. | |
| Worn crankshaft thrust bearings | Replace the crankshaft and bearings as required | |
| Engine misfire with abnormal valve train noise. | Stuck valves. (Carbon build up on the valve stem) | Repair or replace as required |
| Excessive worn or mis-aligned timing chain Out of specification valve clearances | Replace the timing chain and sprocket as required. | |
| Worn camshaft lobes. | Replace the camshaft and valve lifters. | |
| Engine misfire with coolant consumption | Faulty cylinder head gasket or other damage to the cylinder head and engine block cooling system. Coolant consumption may or may not cause the engine to overheat. | Inspect the cylinder head and engine block for damage to the coolant passages and/or a faulty head gasket. Repair or replace as required. |
| Engine misfire with excessive oil consumption | Worn valves, guides and/or valve stem oil seals. | Repair or replace as required. |
| Worn piston rings. (Oil consumption may or may not cause the engine to misfire) | Inspect the cylinder for a loss of compression. Repair or replace as required. | |
| Engine noise on start-up, but only lasting a few seconds. (Check and compare with known good vehicle to determine normal condition.) | Incorrect oil viscosity | Drain the oil. Install the correct viscosity oil. |
| Worn crankshaft thrust bearing. | Inspect the thrust bearing and crankshaft. Repair or replace as required. | |
| Upper engine noise, regardless of engine speed. | Low oil pressure | Repair or replace as required. |
| Broken valve spring. | Replace the valve spring. | |
| Worn or dirty valve lifters. | Replace the valve lifters. | |
| Stretched or broken timing chain and/or damaged sprocket teeth. | Replace the timing chain and sprockets. | |
| Worn timing chain tensioner, if applicable. | Replace the timing chain tensioner as required. | |
| Worn camshaft lobes. | Inspect the camshaft lobes. Replace the timing camshaft and valve lifters as required. | |
| Out of specification valve clearances Worn valve guides or valve stems. | Inspect the valves and valve guides, then repair or replace as required. | |
| Stuck valves. (Carbon on the valve stem or valve seat may cause the valve to stay open. | Inspect the valves and valve guides, then repair or replace as required. | |
| Worn drive belt, idler, tensioner and bearing. | Replace as required | |
| Lower engine noise, regardless of engine speed | Low oil pressure | Repair or required. |
| Loose or damaged flywheel. | Repair or replace the flywheel. | |
| Damaged oil pan, contacting the oil pump screen. | Inspect the oil pan. Inspect the oil pump screen. Repair or replace as required. | |
| Oil pump screen loose, damaged or restricted. | Inspect the oil pump screen. Repair or replace as required. | |
| Excessive piston-to-cylinder bore clearance. | Inspect the piston, piston pin and cylinder bore. Repair or replace as required. | |
| Excessive piston pin-to-piston clearance | Inspect the piston, piston pin and the connecting rod. Repair or replace as required. | |
| Excessive connecting rod bearing clearance | Inspect the following components and repair or replace as required. The connecting rod bearings. The connecting rods. The crankshaft pin journals. | |
| Excessive crankshaft bearing clearance | Inspect the following components, and repair or replace as required. The crankshaft bearings. The crankshaft main journals. The cylinder block | |
| Incorrect piston, piston pin and connecting rod installation | Verify the piston pins and connecting rods are installed correctly. Repair as required. | |
| Engine noise under load | Low oil pressure | Repair or replace as required. |
| Excessive connecting rod bearing clearance | Inspect the following components and repair or replace as required : The connecting rod bearings. The connecting rods. The crankshaft | |
| Excessive crankshaft bearing clearance | Inspect the following components, and repair or replace as required. The crankshaft bearings. The crankshaft main journals. The cylinder block. | |
| Engine will not crank-crankshaft will not rotate | Hydraulically locked cylinder Coolant/antifreeze in cylinder. Oil in cylinder. Fuel in cylinder | Remove spark plugs and check for fluid. Inspect for broken head gasket. Inspect for cracked engine block or cylinder head. Inspect for a sticking fuel injector and/or leaking fuel regulator. |
| Broken timing chain and/or timing chain and/or timing chain gears. | Inspect timing chain and gears. Repair as required. | |
| Material in cylinder Broken valve Piston material Foreign material | Inspect cylinder for damaged components and/or foreign materials. Repair or replace as required. | |
| Seized crankshaft or connecting rod bearings. | Inspect crankshaft and connecting rod bearing. Repair as required. | |
| Bent or broken connecting rod. | Inspect connecting rods. Repair as required. | |
| Broken crankshaft | Inspect crankshaft. Repair as required. |
SYMPTOM REFERENCE CHART