Ignition MITSUBISHI 3000GT 1994 2.G Workshop Manual

Downloaded from www.Manualslib.com manuals search engine 16-38ENGINE ELECTRICAL - Ignition System
STANDARD WAVE-FORM
Observation Conditions
FUNCTIONSECONDARY
\
\j’i
IPATTERN HEIGHTHIGH (or LOW)1
PATTERN SELECTORRASTER
Engine revolutions
Curb idle speed
kV
Secondary
ignition
voltagewave-form
-6
Ignition voltage(Point D)
Dwell sectionSpark line (Point A)
/Wave damping reduction section
(Point B)
/
Time
7EL0147
Observation conditions (Only PAlTERN SELECTOR below changes from the above conditions)
PATTERN SELECTOR
DISPLAY
Secondary
ignition
voltagewave-formt
No. 1 Cylinder
No. 2 Cylinderignition noiseNo. 3 Cylinder
ignition noiseNo. 4 Cylinder
No. 5 CylinderNo. 6 Cylinder(Waveform is ignition noise ignition noise
TimeI)I7EL0148
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Downloaded from www.Manualslib.com manuals search engine ENGINE ELECTRICAL - Ignition System16-39
Wave-form Observation PointsPoint A: The height, length and
slope~of the spark line (refer to abnormal wave-form examples 1, 2, 3
and 4) show the following ‘trends.’\
Spark linePlug gapCondition of Compression Concentration
electrode
forceIgnition timing Sparkof air mixture
plug cable
LengthLongSmallNormal.
LowRichAdvancedLeak
ShortLarge
Large wear
HighLeanRetardedHigh
resistance
Height
HighLargeLarge wearHighLeanRetardedHigh
resistance
LowSmallNormal
Low
Rich _AdvancedLeak
SlopeLargePlug is fouled
-
Point B: Number of vibrations in reduction vibration section (Refer to abnormal wave-form example 5)
Point C: Number of vibrations at beginning of dwell section (Refer to abnormal wave-form example 5)
Point D: Ignition voltage height (distribution per each cylinder) shows the following trends.
Ignition
voltagePlug gapCondition of CompressionConcentration
electrodeIgnition timing Spark
forceof air mixtureplugcable
HighLarge
Large wearHighLean
RetardedHigh
resistance
LowSmallNormal
LowRich
AdvancedLeak
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Downloaded from www.Manualslib.com manuals search engine 16-40ENGINE ELECTRICAL - Ignition System
EXAMPLES OF ABNORMAL WAVE-FORMS
off.
and abnormal wave-form exam-
(Causinga dual ignition)
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Downloaded from www.Manualslib.com manuals search engine ENGINE ELECTRICAL - lanition Svstem16-41
/
L
i
Analyzer
GroundL
01L1008
STANDARD WAVE-FORM
Observation ConditionsIGNITION PRIMARY VOLTAGE WAVE-FORM
CHECK
MEASUREMENT METHOD
(1)Remove the ignition coil connector and connect the special
tool (harness connector: MD998464) in between.
(2) When observing the No. 1 - No. 4 cylinder group, connectthe primary pickup of the analyzer probe to the ignition
coil side connector terminal No. 2 (black clip on the special
tool).
For the No. 2 - No. 5 cylinder group, connect to terminal
No. 1 (red clip), and for the No. 3
- No. 6 cylinder group,connect to terminal No. 4 (white clip).
(3) Ground the primary pickup ground terminal.
(4) Clamp the spark plug cable with the trigger pickup.
NOTE(1) Clamp the spark plug cable of cylinder No. 1, No.
2 or No. 3 which belongs to the same group of the
cylinder to which the primary pickup is connected.
(2) The wave-form of any cylinder in the same group
is displayed on the left side of the screen.
FUNCTION
PRIMARY
PATTERN HEIGHTHIGH (or LOW)
PAVERN SELECTOR
Engine revolutionsRASTER
Curb idle speed
(V)
100
Primary Primary*ignition ignition
voltage voltage
wave-form
owave-formkr
0
Zener
voltage
(Point C)
Dwell
section
b
Spark line (Point A)
/b-4
Wave damping reduction section (Point B)
/
Time
7EL0149
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Downloaded from www.Manualslib.com manuals search engine 16-42ENGINE ELECTRICAL - Ignition System
Observation conditions (Only PAlTERN SELECTOR below changes from the above conditions.)
PATTERN SELECTOR
DISPLAY1
(V) -100
-
Primary
ignition
voltage
i
wave-form
0No. 1 (or No. 4)
cylinderNo. 2 (or No. 5)cylinderNq.3(orNo.6) No.4(orNo. 1) No.5(orNo.2) No.6 (orNo. 1)
ignition noisecylinder
ignition noisecylinder
cylinder
ignition noisecylinder
/
I
/ignition noise
:./ /Neutral
section
/
Time
7EL0151
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Wave-form Observation Points/
LPoint A: The height, length and slope of the spark line (refer to abnormal wave-form examples 1, 2, 3and 4) show the following trends.
Spark linePlug gapCondition of CompressionConcentra-Ignition timing High tension
electrodeforcetion of air mix-cable
tureLength Long
SmallNormalLowRichAdvanced
Leak
Short
LargeLarge wearHighLeanRetardedHigh
resistanceHeight High
LargeLarge wearHighLeanRetardedHigh
resistance
LowSmall
NormalLowRichAdvancedLeak
SlopeLargePlug is fouled-
Point B: Number of vibrations in reduction vibration section
(Refer to abnormal wave-form example 5)
Number of vibrationsCoil and condenser
I3 or higher/ Normal
Except aboveAbnormal
Point C: Height of Zener voltage
Height of Zener voltageProbable cause
HigherProblem in Zener diode
LowerAbnormal resistance in pri-
mary coil circuit
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EXAMPLES OF ABNORMAL WAVE-FORMS
Abnormal wave-form
Wave characteristics
Cause of problem
Example 1Spark line is high and short.
Spark plug gap is too large.
z01P0210
Example 2Spark line is low and long, and is
sloping. Also, the second half of
Spark plug gap is too small.the spark line is distorted. This
could be a result of misfiring.3
i
Example 3
zo1Po211
Spark line is low and long, and is
sloping. However, there is almostSpark plug gap is fouled.
no spark line distortion.
ZOlPO212
Example 4Spark line is high and short.Spark plug cable is nearly falling
off. (Causing a dual ignition)
ZOlPO213
Example 5No waves in wave damping set-tion.Rare short in ignition coil.
-l
zolPo214
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Downloaded from www.Manualslib.com manuals search engine ENGINE ELECTRICAL - Ignition System16-45 l
IGNITION SYSTEM
LREMOVAL AND INSTALLATIONI
i
27EN0520
413 NmIlOft.lbs.
d
12 Nm
9 ft.lbs.
22 Nm16ftAbs.B678
W1
,A4
Removal stepsl Intake manifold plenum (Refer to
GROUP
1.5 - Intake Manifold.)1. Center cover
2. Spark plug cable
3. Spark plug
4. Ignition coil
5. Ignition power transistor
6. Crankshaft position sensor
cl 992 models>9 Nm
7
ft.lbs.u 16FO453
00662527
7. O-ring cl992 models>
8. Clamp Camshaft position sensor, Crankshaft
positionsensor removal steps models>l Timing belt cover (Refer to GROUP
11 - Timing Belt)
9. Camshaft position sensor
10. Crankshaft position sensor
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Downloaded from www.Manualslib.com manuals search engine 16-46ENGINE ELECTRICAL - Ignition Svstem
27ELOO95JINSTALLATION SERVICE POINTS.A+CRANKSHAFT
POSITION SENSOR INSTALLATION

(1) Turn the crankshaft so that the No. 1 cylinder is at
compression top dead center.
Caution
Be careful not to turn it to the No.
4 cylinder com-
pression top dead center by mistake.
(2) Install, lining up the matchmarks on the crankshaft
position sensor housing and the coupling.
,B+SPARK PLUG CABLE INSTALLATION
Improper arrangement of spark plug cables will induce
voltage between the cables, causing miss firing and devel-
oping a surge at acceleration in high-speed operation.
Therefore, be careful to arrange the spark plug cables
properly by the following procedure.
1.install the spark plug cable clamps as shown in the
illustration.
2.The numerals on the support and clamp indicate the
spark plug cable No.
3.Pay attention to the following items when the spark
plug cables are installed.
(1)Install the cables securely to avoid possible contact
with metal parts.(2) Install the cables neatly, ensuring they are not
too tight, loose, twisted or kinked.
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Spark plugcable No. 1
Spark plugr cable No. 4
\Spark plug‘de No. 6
sparK piug
cable No. 2
Approx.60 mm
(2,36in.) Approx
I(3.15in.)cup to 1992
model>
Approx. 80 mm (3.15 in.)TIC only

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