Ignition coil
Igniter
Ignition switch
Main
fuse
Injector resistor
Fuel injector
Crankshaft
position sensor
Camshaft
position sensor
Ground
at engine “I / G COIL METER”
Main relay
6-68 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
DTC P0300 RANDOM MISFIRE DETECTED (Misfire detected at 2 or more
cylinders)
DTC P0301 CYLINDER 1 MISFIRE DETECTED
DTC P0302 CYLINDER 2 MISFIRE DETECTED
DTC P0303 CYLINDER 3 MISFIRE DETECTED
CIRCUIT DESCRIPTION
ECM (PCM) monitors crankshaft revolution speed and engine speed via the crankshaft position sensor and cylin-
der No. via the camshaft position sensor. Then it calculates the change in the crankshaft revolution speed and from
how many times such change occurred in every 200 or 1000 engine revolutions, it detects occurrence of misfire.
When ECM (PCM) detects a misfire (misfire rate per 200 revolutions) which can cause overheat and damage to
the three way catalytic converter, it makes the malfunction indicator lamp (MIL) flash as long as misfire occurs at
that rate.
After that, however, when the misfire rate drops, MIL remains ON until it has been judged as normal 3 times under
the same driving conditions.
Also, when ECM (PCM) detects a misfire (misfire rate per 1000 revolutions) which will not cause damage to three
way catalytic converter but can cause exhaust emission to be deteriorated, it makes MIL light according to the 2
driving cycle detection logic.
ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-69
Below
specified value DTC DETECTING CONDITION
POSSIBLE CAUSE
Engine under other than high revolution condition
Not on rough road
Engine speed changing rate
Manifold absolute
pressure changing rate
Throttle opening changing rate
Misfire rate per 200 or 1000 engine revolutions (how
much and how often crankshaft revolution speed
changes) is higher than specified valueEngine overheating
Vacuum leaks (air inhaling) from air intake system
Ignition system malfunction (spark plug(s), high-
tension cord(s), ignition coil assembly)
Fuel pressure out of specification
Fuel injector malfunction (clogged or leakage)
Engine compression out of specification
Valve lash (clearance) out of specification
Manifold absolute pressure sensor malfunction
Engine coolant temp. sensor malfunction
PCV valve malfunction
EVAP control system malfunction
DTC CONFIRMATION PROCEDURE
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester.
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Check vehicle and environmental condition for:
–Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
–Ambient temp.: –10C, 14F or higher
–Intake air temp.: 70C, 158F or lower
–Engine coolant temp.: –10 – 11 0C, 14 – 230F
4) Start engine and keep it at idle for 2 min. or more.
5) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.
6) If DTC is not detected at idle, consult usual driving based on information obtained in “Customer complaint analy-
sis” and “Freeze frame data check”.
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-23
ConditionPossible Cause]Referring Item
Low oil pressureImproper oil viscosity
Malfunctioning oil pressure switch
Clogged oil strainer
Functional deterioration of oil pump
Worn oil pump relief valve
Excessive clearance in various sliding partsEngine oil and oil filter change in
Section 0B
Oil pressure switch inspection in
Section 8
Oil pan and oil pump strainer
cleaning in Section 6A1
Oil pump in Section 6A1
Oil pump in Section 6A1
Engine noise
Note: Before
checking mechanical
noise, make sure
that:
Specified spark
plug in used.
Specified fuel is
used.Valve noise
Improper valve lash
Worn valve stem and guide
Weak or broken valve spring
Warped or bent valve
Piston, ring and cylinder noise
Worn piston, ring and cylinder bore
Connecting rod noise
Worn rod bearing
Worn crank pin
Loose connecting rod nuts
Low oil pressure
Crankshaft noise
Low oil pressure
Worn bearing
Worn crankshaft journal
Loose bearing cap bolts
Excessive crankshaft thrust play
Valve lash in Section 6A1
Valves inspection in Section 6A1
Valve springs inspection in
Section 6A1
Valves inspection in Section 6A1
Pistons and cylinders inspection
in Section 6A1
Crank pin and connecting rod
bearing inspection in Section 6A1
Crank pin and connecting rod
bearing inspection in Section 6A1
Connecting rod installation in
Section 6A1
Previously outlined
Previously outlined
Crankshaft and bearing
inspection in Section 6A1
Crankshaft and bearing
inspection in Section 6A1
Crankshaft inspection in
Section 6A1
Crankshaft thrust play inspection
in Section 6A1
6-1-24 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
ConditionPossible CauseReferring Item
OverheatingInoperative thermostat
Poor water pump performance
Clogged or leaky radiator
Improper engine oil grade
Clogged oil filter or oil strainer
Poor oil pump performance
Faulty radiator fan control system
Dragging brakes
Slipping clutch
Blown cylinder head gasketThermostat in Section 6B
Water pump in Section 6B
Radiator in Section 6B
Engine oil and oil filter change in
Section 0B
Oil pressure check in Section 6A1
Oil pressure check in Section 6A1
Radiator fan control system in
Section 6E2
Trouble diagnosis in Section 5
Trouble diagnosis in Section 7C
Cylinder head in Section 6A1
Poor gasoline
mileageIgnition system out of order
Leaks or loose connection of high-tension cord
Faulty spark plug (improper gap, heavy deposits
and burned electrodes, etc.)
Engine and emission control system out of
order
Malfunctioning EGR valve
High idle speed
Poor performance of TP sensor, ECT sensor or
MAP sensor
Faulty EGR valve
Faulty fuel injector(s)
Faulty ECM (PCM)
Low compression
Others
Poor valve seating
Dragging brakes
Slipping clutch
Thermostat out of order
Improper tire pressure
High-tension cords in Section 6F1
Spark plugs in Section 6F1
EGR system in Section 6E2
Refer to item “Improper engine
idle speed” previously outlined
TP sensor, ECT sensor or MAP
sensor in Section 6E2
EGR system in Section 6E2
Diagnostic Flow Table B-1
Previously outlined
Valves inspection in Section 6A1
Trouble diagnosis in Section 5
Trouble diagnosis in Section 7C
Thermostat in Section 6B
Refer to Section 3F
Excessive engine
oil consumptionOil leakage
Blown cylinder head gasket
Leaky camshaft oil seals
Oil entering combustion chamber
Sticky piston ring
Worn piston and cylinder
Worn piston ring groove and ring
Improper location of piston ring gap
Worn or damaged valve stem seal
Worn valve stem
Cylinder head in Section 6A1
Camshaft in Section 6A1
Piston cleaning in Section 6A1
Pistons and cylinders inspection
in Section 6A1
Pistons inspection in Section 6A1
Pistons assembly in Section 6A1
Valves removal and installation in
Section 6A1
Valves inspection in Section 6A1
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-69
Ignition coil assembly
for No.1 & No.4 spark plugs
Ignition coil assembly
for No.2 & No.3 spark plugs
Ignition switch
Main relay
Main
fuseRelay box
To ignition switch
CKP sensorCMP sensorNo.1 injector
No.2 injector
No.3 injector
No.4 injector Fuse box
DTC P0300 RANDOM MISFIRE DETECTED (Misfire detected at 2 or more
cylinders)
DTC P0301 CYLINDER 1 MISFIRE DETECTED
DTC P0302 CYLINDER 2 MISFIRE DETECTED
DTC P0303 CYLINDER 3 MISFIRE DETECTED
DTC P0304 CYLINDER 4 MISFIRE DETECTED
CIRCUIT DESCRIPTION
ECM (PCM) monitors crankshaft revolution speed and engine speed via the crankshaft position sensor and cylin-
der No. via the camshaft position sensor. Then it calculates the change in the crankshaft revolution speed and from
how many times such change occurred in every 200 or 1000 engine revolutions, it detects occurrence of misfire.
When ECM (PCM) detects a misfire (misfire rate per 200 revolutions) which can cause overheat and damage to
the three way catalytic converter, it makes the malfunction indicator lamp (MIL) flash as long as misfire occurs at
that rate.
After that, however, when the misfire rate drops, MIL remains ON until it has been judged as normal 3 times under
the same driving conditions.
Also, when ECM (PCM) detects a misfire (misfire rate per 1000 revolutions) which will not cause damage to three
way catalytic converter but can cause exhaust emission to be deteriorated, it makes MIL light according to the 2
driving cycle detection logic.
Below
specified value
6-1-70 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
1. CKP sensor signal
2. No.1 fuel injector signal
3. No.3 fuel injector signal
4. Fuel injection time
Display of fuel injection signal using oscilloscope
Waveforms at specified idle speed5ms/Div
DTC DETECTING CONDITIONPOSSIBLE CAUSE
Engine under other than high revolution condition
Not on rough road
Engine speed changing rate
Manifold absolute
pressure changing rate
Throttle opening changing rate
Misfire rate per 200 or 1000 engine revolutions (how
much and how often crankshaft revolution speed
changes) is higher than specified valueEngine overheating
Vacuum leaks (air inhaling) from air intake system
Ignition system malfunction (spark plug(s), high-
tension cord(s), ignition coil assembly)
Fuel pressure out of specification
Fuel injector malfunction (clogged or leakage)
Engine compression out of specification
Valve lash (clearance) out of specification
Manifold absolute pressure sensor malfunction
Engine coolant temp. sensor malfunction
PCV valve malfunction
EVAP control system malfunction
EGR system malfunction
DTC CONFIRMATION PROCEDURE
NOTE:
Among different types of random misfire, if misfire occurs at cylinders 1 and 4 or cylinders 3 and 2 simulta-
neously, it may not possible to reconfirm DTC by using the following DTC confirmation procedure. When
diagnosing the trouble of DTC P0300 (Random misfire detected) of the engine which is apparently misfir-
ing, even if DTC P0300 cannot be reconfirmed by using the following DTC confirmation procedure, pro-
ceed to the following Diag. Flow Table.
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester.
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Check vehicle and environmental condition for:
–Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
–Intake air temp.: between –10C and 80C (14F and 176F)
–Engine coolant temp.: –10C, 14F or higher
4) Start engine and keep it at idle for 2 min. or more.
5) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.
6) If DTC is not detected at idle, consult usual driving based on information obtained in “Customer complaint analy-
sis” and “Freeze frame data check”.
Reference
6A-2 ENGINE MECHANICAL (G10, 1-CAM 6-VALVES ENGINE)
ON-VEHICLE SERVICE
ENGINE VACUUM CHECK
The engine vacuum that develops in the intake line is a good indica-
tor of the condition of the engine. The vacuum checking procedure
is as follows:
1) Warm up engine to normal operating temperature.
2) With engine stopped, remove blind plug hose from intake man-
ifold and connect special tool (vacuum gauge and joint) to va-
cated threaded hole.
Special Tool
(A): 09915-67311
3) Run engine at specified idle speed (see Section 6E), and read
vacuum gauge. Vacuum should be within the following specifi-
cation.
Vacuum specification: 52.6 – 65.8 kPa (40 – 50 cm
.Hg,
15.7 – 19.7 in
.Hg) at specified
idling speed
4) After checking, apply sealant to thread of blind plug and install
it to intake manifold.
OIL PRESSURE CHECK
NOTE:
Prior to checking oil pressure, check the followings.
Oil level in oil pan.
If oil level is low, add oil up to Full level hole on oil level
gauge.
Oil quality.
If oil is discolored, or deteriorated, change it.
For particular oil to be used, refer to the table in Section 0B.
Oil leaks.
If leak is found, repair it.
1) Using special tool (Oil filter wrench), remove oil filter.
2) After removing oil filter, remove oil pressure switch (1) from cylin-
der block.
6A-20 ENGINE MECHANICAL (G10, 1-CAM 6-VALVES ENGINE)
CAUTION:
Don’t turn camshaft or start engine (i.e., valves should not be operated) for about half an hour after
reinstalling hydraulic valve lash adjusters and camshaft. As it takes time for valves to settle in place,
operating engine within half an hour after their installation may cause interference to occur between
valves and piston.
If air is trapped in valve lash adjuster, valve may make tapping sound when engine is operated after
valve lash adjuster is installed. In such a case, run engine for about half an hour at about 2,000 – 3,000
r / min., and then air will be purged and tapping sound will cease. Should tapping should not cease,
it is possible that valve lash adjuster is defective. Replace it if defective.
If defective adjuster can’t be located by hearing among 6 of them, check as follows.
1) Stop engine and remove cylinder head cover.
2) Push adjuster downward by hand (with less than 15 kg or 33 lbs force) when cam crest is not on
adjuster to be checked and check if clearance exists between cam and adjuster. If it does, adjuster
is defective and needs replacement.
VALVE LASH ADJUSTER NOISE DIAGNOSIS
In case of the followings, valve lash adjuster noise may be caused by air trapped into valve lash adjusters.
Vehicle is left for 24 hours or more.
Engine oil is changed.
Hydraulic lash adjuster is replaced or reinstalled.
Engine is overhauled.
If noise from valve lash adjusters is suspected, perform the following checks.
1) Check engine oil for the followings.
Oil level in oil pan
If oil level is low, add oil up to Full level hole on oil level gauge.
Oil quality
If oil is discolored, or deteriorated, change it.
For particular oil to be used, refer to Section 0B.
Oil leaks
If leak is found, repair it.
Oil pressure (refer to Oil Pressure Check in this section)
If defective pressure is found, repair it.
2) Run engine for about half an hour at about 2,000 to 3,000 r / min., and then air will be purge and tapping sound
will cease.
3) Should tapping sound not cease, it is possible that hydraulic valve lash adjuster is defective.
Replace it if defective.
If defective adjuster can’t be located by hearing among 16 of them, check as follows.
a) Stop engine and remove cylinder head cover.
b) Push adjuster downward by hand (with less than 20 kg or 44 lbs. Force) when cam crest is not on adjuster
to be check if clearance exists between cam and adjuster.
If it does, adjuster is defective and needs replacement.