Compression Pressure Inspection
Note. If the there is lack of power, excessive oil consumption or poor fuel economy, measure the compression pressure.
Scheme 18
Scheme 19
- Warm up engine until the normal operating temperature (80~95°C (176-203°F)).
- Remove the surge tank. Refer to «INTAKE AND EXHAUST SYSTEM»(ref-584173) .
- Remove the ignition coil connectors (A) and ignition coils (B).
- Remove the spark plugs. Using a 16 mm plug wrench, remove the 6 spark plugs.
- Check cylinder compression pressure. Insert a compression gauge into the spark plug hole. Fully open the throttle. Crank the engine over 7 times to measure compression pressure. NOTE: Always use a fully charged battery to obtain engine speed of 250 RPM or more. Repeat step 1 though 3 for each cylinder. NOTE: This measurement must be done in as short a time as possible. Compression pressure: 1, 029 kPa (10.5kgf/cm 2 , 149 psi) (250~400 RPM) Minimum pressure: 882 kPa (9.0kgf/cm 2 , 128 psi) Difference between each cylinder: 98 kPa (1.0kg/cm 2 , 14 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 step 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 the spark plugs.
- Install the ignition coils and ignition connectors.
- Install the surge tank. Refer to «INTAKE AND EXHAUST SYSTEM»(ref-584173) .
Troubleshooting
| Symptom | Suspect area | Remedy |
|---|---|---|
| Engine misfire with abnormal internal lower engine noises. | Worn crankshaft bearings. Loose or damaged engine drive plate. | Replace the crankshaft and bearings as required. Repair or replace the drive plate 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 buildup on the valve stem) | Repair or replace as required. |
| Excessive worn or mis-aligned timing chain. | 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 and/or cranking 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. | 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. | |
| Worn valve guides or valve stems. | Inspect the valves and valve guides, then repair 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 as required. | |
| Worn drive belt, idler, tensioner and bearing. | Replace as required. | |
| Lower engine noise, regardless of engine speed. | Low oil pressure. | Repair as required. |
| Loose or damaged drive plate. | Repair or replace the drive plate. | |
| 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 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 as required. The connecting rod bearings. The connecting rods. The crankshaft pin journals. | |
| Excessive crankshaft bearing clearance. | Inspect the following components, and repair 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 as required : The connecting rod bearings. The connecting rods. The crankshaft. | |
| Excessive crankshaft bearing clearance. | Inspect the following components, and repair 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. |
PROBLEM SYMPTOMS