spark plugs MITSUBISHI LANCER 2006 Workshop Manual

IGNITION SYSTEM
ENGINE ELECTRICAL16-30
IGNITION SYSTEM
GENERAL INFORMATIONM1163000100294
This system is equipped with two ignition coils (A and
B) with built-in power transistors for the No. 1 and
No. 4 cylinders and the No. 2 and No. 3 cylinders
respectively.
Interruption of the primary current flowing in the pri-
mary side of ignition coil A generates a high voltage
in the secondary side of ignition coil A. The high volt
-
age thus generated is applied to the spark plugs of
No. 1 and No. 4 cylinders to generate sparks. At the
time that the sparks are generated at both spark
plugs, if one cylinder is at the compression stroke,
the other cylinder is at the exhaust stroke, so that
ignition of the compressed air/fuel mixture occurs
only for the cylinder which is at the compression
stroke.
In the same way, when the primary current flowing in
ignition coil B is interrupted, the high voltage thus
generated is applied to the spark plugs of No. 2 and
No. 3 cylinders.
The engine-ECU or engine-A/T-ECU
turns the two power transistors inside the ignition
coils alternately on and off. This causes the primary
currents in the ignition coils to be alternately inter
-
rupted and allowed to flow to fire the cylinders in the
order 1-3-4-2.
The engine-ECU or engine-A/T-ECU
determines which ignition coil should be controlled
by means of the signals from the camshaft position
sensor which is incorporated in the camshaft and
from the crank angle sensor which is incorporated in
the crankshaft. It also detects the crankshaft position
in order to provide ignition at the most appropriate
timing in response to the engine operation condi
-
tions. It also detects the crankshaft position in order
to provide ignition at the most appropriate timing in
response to the engine operation conditions.
When the engine is cold or operated at high alti-
tudes, the ignition timing is slightly advanced to pro-
vide optimum performance.
When the automatic transmission shifts gears, the
ignition timing is also retarded in order to reduce out
-
put torque, thereby alleviating shifting shocks.
SYSTEM DIAGRAM
AK101074
Air flow sensor
<4G6> MAP sensor <4G1>
Intake air temperatur
sensor
Engine coolant
temperature sensor
Camshaft position
sensor
Crank angle sensor
Barometric pressure
sonsor <4G6>
Detonatoin sensor
Ignition switch-ST Engine-A/T-
ECU Engine-ECU

Ignition coil B
Cylinder No. 23 4
AG
1
Spark plug Ignition coil A
Ignition
switch
Battery

IGNITION SYSTEM
ENGINE ELECTRICAL16-32
ON-VEHICLE SERVICE
IGNITION COIL (WITH BUILT-IN POWER
TRANSISTOR) CHECK
M1163001200324
Check by the following procedure, and replace if
there is a malfunction.
SECONDARY COIL RESISTANCE CHECK
AKX01264
Measure the resist ance bet we en the high- volt ag e
terminals of th
e ign i tio n coil.
St andard va lue: 8.5 − 11 .5 kΩ
PRIM AR Y COIL AND POWER TRANSIS-
TO R CONTINUITY CHECK
NO TE: .•
AKX01265 AD
1.5 V
1 23
+
–
An analogue-t y pe circuit t e ster shou ld be use d .
•Connect the n egative (-) pro v e of the circuit t e ster
to t
e rminal No. 1.
CAUTION
This test must be performed quickly (in less than
10 seconds) to prevent coil from burning and
power transistor from breakage.
1.5 V power supply
between 2
− 3
Continuity between 1 −
2
When current is flowingContinuity
When current is not
flowing
No continuity
RESISTIVE CORD CHECK
M1163001400124
AKX00382
Measure the resistance of the all spark plug cables.
1. Check cap and coating for cracks.
2. Measure resistance.
Limit: Maximum 19 kΩ
SPARK PLUG CHECK AND CLEANING
<4G1>
M1163004300342
CAUTION
When pulling off the spark plug cable from the
plug always hold the cable cap, not the cable.
1. Remove the spark plug cables.
2. Remove the spark plugs.
3. Check for burned out electrode or damaged insulator. Check for even burning.
4. Remove carbon deposits with wire brush or plug cleaner. Remove sand from plug screw with
compressed air.
AKX01272 AG
Plug gap gauge
Measurement
direction
5. Use a plug gap gauge to check that the plug gap is within the standard value range.
Standard value: 1.0 − 1.1 mm
If the plug gap is not within the standard value
range, adjust by bending the earth electrode.
CAUTION
Be careful not to allow foreign matter in cylin-
ders.
6. Clean the engine plug holes.
7. Install the spark plugs.

IGNITION SYSTEM
ENGINE ELECTRICAL16-33
SPARK PLUG CHECK AND CLEANING
<4G6>
M1163004300353
CAUTION
When pulling off the spark plug cable from the
plug always hold the cable cap, not the cable.
1. Remove the spark plug cables.
2. Remove the spark plugs.
CAUTION
•Do not attempt to adjust the gap of the iridium
plug.
•
AKX00383 AL
Platinum
tipIridium
tip
Always use a plug cleaner and finish cleaning
within 20 seconds. Do not use wire brushes.
Otherwise, the iridium and platinum tip may
be damaged.
3. Check the plug gap and re
place if the limit is
exceeded.
Standard value: 1.0 − 1.1 mm
Limit: 1.3 mm
CAUTION
Be careful not to allow foreign matter in cylin-
ders.
4. Clean the engine plug holes.
5. Install the spark plugs.
CAMSHAFT POSITION SENSOR CHECK
M1163004400219
Check the camshaft position sensor circuit if
self-diagnosis code No. P0340 is shown.
(Refer to GROUP 13A − Troubleshooting − Inspection
chart for diagnosis code <4G1>
P.13A-15 or GROUP
13B − Troubleshooting − Inspection chart for diagnosis
code <4G6>
P.13B-15 ).
CRANK ANGLE SENSOR CHECK
M1163004500272
Check the crank angle sensor circuit if self-diagnosis
code No. P0335 is shown.
(Refer to GROUP 13A − Troubleshooting − Inspection
chart for diagnosis code <4G1>
P.13A-15 or GROUP
13B − Troubleshooting − Inspection chart for diagnosis
code <4G6>
P.13B-15 ).
DETONATION SENSOR CHECKM1163002900047
Check the detonation sensor circuit if self-diagnosis
code No. P0325 is shown.
(Refer to GROUP 13A − Troubleshooting − Inspection
chart for diagnosis code <4G1>
P.13A-15 or GROUP
13B − Troubleshooting − Inspection chart for diagnosis
code <4G6>
P.13B-15).
IGNITION SECONDARY VOLTAGE
WAVEFORM CHECK USING AN
OSCILLOSCOPE
M1163001700170
MEASUREMENT METHOD
1. Clamp the secondary pickup around the spark
plug cable.
NOTE: .
•The peak ignition voltage will be reversed
when the spark plug cables No. 2 and No. 4,
or No. 1 and No. 3 cylinders are clamped.
•Because of the two-cylinder simultaneous igni-
tion system, the waveforms for two cylinders in
each group appear during waveform observa
-
tion (No. 1 cylinder - No. 4 cylinder, No. 2 cyl-
inder - No. 3 cylinder). However, waveform
observation is only applicable for the cylinder
with the spark plug cable clamped by the sec
-
ondary pickup.
•Identifying which cylinder waveform is dis-
played can be difficult. For reference, remem-
ber that the waveform of the cylinder attached
to the secondary pickup will be displayed as
stable.
2. Clamp the spark plug cable with the trigger pickup.
NOTE: Clamp the trigger pickup to the same
spark plug cable clamped by the secondary
pickup.