Component Tests and General Diagnostics
Inspection
Compression Pressure
NOTE:
If the there is lack of power, excessive oil consumption or poor fuel economy, measure the compression pressure.
1. Warm up engine until the normal operating temperature(80 - 95°C(176-203°F)).
2. Remove the surge tank.
3. Disconnect the LH/RH ignition coil connectors and then remove the ignition coils.
4. Remove the spark plugs.
Using a 16mm plug wrench, remove the 6 spark plugs.
5. Check cylinder compression pressure.
(1) Insert a compression gauge into the spark plug hole.
(2) Fully open the throttle.
(3) 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.
(4) Repeat step 1) though 3) for each cylinder.
NOTE:
This measurement must be done in as short a time as possible.
Compression pressure :
1,029kPa (10.5kgf/cm2, 149psi) (250 - 400 rpm)
Minimum pressure :
882kPa (9.0kgf/cm2, 128psi)
Difference between each cylinder :
98kPa (1.0kg/cm2, 14psi) or less
(5) 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.
A. If adding oil helps the compression, it is likely that the piston rings and/or cylinder bore are worn or damaged.
B. If pressure stays low, a valve may be sticking or seating is improper, or there may be leakage past the gasket.
6. Reinstall the spark plugs.
Tightening torque:
14.7 - 24.5 N.m (1.5 - 2.5 kgf.m, 10.8 - 18.1 lb-ft)
7. Install the ignition coils and ignition connectors.
Tightening torque:
9.8 - 11.8 N.m (1.0 - 1.2 kgf.m, 7.2 - 8.7 lb-ft)
8. Install the surge tank.
Valve Clearance Inspection And Adjustment
NOTE:
Inspect and adjust the valve clearance when the engine is cold (Engine coolant temperature : 20°C(68°F)) and cylinder head is installed on the cylinder block.
1. Remove the engine cover.
2. Remove air cleaner assembly.
3. Remove the surge tank.
4. Remove the cylinder head cover.
5. Set No.1 cylinder to TDC/compression.
(1) Turn the crankshaft pulley clockwise and align its groove with the timing mark "T" of the lower timing chain cover.
(2) Check that the mark of the camshaft timing sprockets are in straight line on the cylinder head surface as shown in the illustration.
If not, turn the crankshaft clockwise one revolution (360°).
NOTE:
Do not rotate engine counterclockwise.
6. Inspect the valve clearance.
(1) With No.1 cylinder at TDC inspect clearances only on the valves shown in diagram below.
Measurement method.
A. Using a thickness gauge, measure the clearance between the tappet and the base circle of camshaft.
B. Record the out-of-specification valve clearance measurements. They will be used later to determine the required replacement adjusting tappet.
Valve clearance
Specification
Engine coolant temperature : 20°C [68°F]
Limit
Intake : 0.10 - 0.30mm (0.0039 - 0.0118in.)
Exhaust : 0.20 - 0.40mm (0.0078 - 0.0157in.)
(2) Turn the crankshaft pulley clockwise one revolution (360°) and align the groove with timing mark "T" of the lower timing chain cover.
(3) With No.4 cylinder at TDC inspect clearances only the valves shown in diagram below.
7. Adjust the intake and exhaust valve clearance.
(1) Set the No.1 cylinder to the TDC/compression.
(2) Remove the timing chain.
NOTE:
Before removing the timing chain, mark the RH/LH timing chain with an identification based on the location of the sprocket because the identification mark on the chain for TDC (Top Dead Center) can be erased.
(3) Remove the fuel pump adapter (A).
(4) Remove the LH/RH camshaft bearing cap (A) and thrust bearing cap (B).
(5) Remove the LH/RH camshaft assembly (A).
(6) Remove the tappets.
(7) Measure the thickness of the removed tappet using a micrometer.
(8) Calculate the thickness of a new tappet so that the valve clearance comes within the specified value.
T :Thickness of removed tappet
A :Measured valve clearance
N :Thickness of new tappet
Intake :N = T + [A - 0.20mm(0.0079in.)]
Exhaust :N = T + [A - 0.30mm (0.0118in.)]
(9) Select a new tappet with a thickness as close as possible to the calculated value.
NOTE:
Shims are available in 41size increments of 0.015mm (0.0006in.) from 3.00mm (0.118in.) to 3.600mm (0.1417in.)
(10) Place a new tappet on the cylinder head.
NOTE:
Apply engine oil at the selected tappet on the periphery and top surface.
(11) Install the intake and exhaust camshaft.
(12) Install the bearing caps.
(13) Install the timing chain.
(14) Turn the crankshaft two turns in the operating direction (clockwise) and realign crankshaft sprocket and camshaft sprocket timing marks.
(15) Recheck the valve clearance.
Valve clearance (Engine coolant temperature : 20°C [68°F])
[Specification]
Intake : 0.17 - 0.23mm (0.0067 - 0.0090in.)
Exhaust : 0.27 - 0.33mm (0.0106 - 0.0129in.)