Ignition System: Testing and Inspection
IGNITION SYSTEM ON-VEHICLE INSPECTIONNOTE: "Cold" and "Hot" in these sentences express the temperature of the coils themselves. "Cold" is from -10 °C (14 °F) to 50 °C (122 °F) and "Hot" is from 50 °C (122 °F) to 100 °C (212 °F).
1. INSPECT SPARK TEST
Check that the spark occurs.
1. Disconnect the high-tension cord from the spark plug.
2. Remove the spark plug.
3. Install the spark plug to the high-tension cord.
4. Ground the spark plug.
5. See if spark occurs while engine is being cranked.
NOTE: To prevent gasoline from being injected from injectors during this test, crank the engine for no more than 5 - 10 seconds at time.
If the spark does not occur, do the test as follows:
2. INSPECT HIGH-TENSION CORDS
a. Remove the high-tension cords.
Disconnect the high-tension cords at the rubber boot. Do not pull on the high-tension cords.
NOTE: Pulling on or bending the cords may damage the conductor inside.
b. Using an ohmmeter, measure the high-tension cord resistance.
Maximum resistance: 25 kohm per cord
If the resistance is greater than maximum, check the terminals.
If necessary, replace the high-tension cord.
c. Reinstall the high-tension cords.
3. INSPECT SPARK PLUGS
NOTE:
- Never use a wire brush for cleaning.
- Never attempt to adjust the electrode gap on a used spark plug.
- Spark plugs should be replaced every 100,000 km (60,000 miles).
a. Disconnect the high-tension cords from the spark plugs.
b. Inspect the electrode.
Using a megger (insulation resistance meter), measure the insulation resistance.
Standard correct insulation resistance: 10 Mohm or more
If the resistance is less than specified, proceed to step (d).
HINT: If a megger is not available, the following simple method of inspection provides fairly accurate results.
- Simple Method:
- Quickly race the engine to 4,000 rpm 5 times.
- Remove the spark plug. (See step (c))
- Visually check the spark plug.
If the electrode is dry ... OK
If the electrode is wet... Proceed to step (d)
- Reinstall the spark plug. (See step (g))
c. Using a 16 mm plug wrench, remove the 4 spark plugs.
d. Visually check the spark plug for thread damage and insulator damage.
If abnormal, replace the spark plug.
e. Inspect the electrode gaps.
Maximum electrode gap for used spark plug: 1.3 mm (0.051 in.)
If the gap is greater than maximum, replace the spark plug.
Correct electrode gap for new spark plug: 1.1 mm (0.043 in.)
NOTE: If adjusting the gap of a new spark plug, bend only the base of the ground electrode. Do not touch the tip. Never attempt to adjust the gap on the used plug
f. Clean the spark plugs.
If the electrode has traces of wet carbon, allow it to dry and then clean with a spark plug cleaner.
Air pressure: Below 588 kPa (6 kgf/sq.cm, 85 psi)
Duration: 20 seconds or less
HINT: If there are traces of oil, remove it with gasoline before using the spark plug cleaner.
g. Using a 16 mm plug wrench, install the 4 spark plugs.
Torque: 18 N.m (180 kgf.cm, 13 ft.lbf)
h. Reconnect the high-tension cords from the spark plugs.
4. INSPECT IGNITION COILS WITH IGNITERS
a. Disconnect the high-tension cords from the ignition coils.
b. Inspect the secondary coil resistance.
Using an ohmmeter, measure the resistance between the
If the resistance is not specified, replace the ignition coil.
c. Reconnect the high-tension cords to the ignition coils.
d. Inspect the igniters. (See procedure spark test)
5. INSPECT CAMSHAFT POSITION SENSOR
a. Disconnect the camshaft position sensor connector.
b. Using an ohmmeter, measure the resistance between terminals.
Resistance:
If the resistance is not specified, replace the sensor.
c. Reconnect the camshaft position sensor connector.
6. INSPECT CRANKSHAFT POSITION SENSOR
a. Disconnect the crankshaft position sensor connector.
b. Using an ohmmeter, measure the resistance between terminals.
Resistance:
If the resistance is not specified, replace the sensor.
c. Reconnect the crankshaft position sensor connector.