1990 MITSUBISHI SPYDER spark plugs

ENGINE (NON-TURBO)>
Scan tool 106
Code General scan tool
No.Multiple Cylinder Mlsfire
43
[Comment]Background
l Excessive engine misfire results in increased catal yst temperature.
l Severe misfire could cause catalyst damage.
l To prevent catalytic converter damage, the PCM moni tors engine misfire.
l The PCM monitors for misfire during most engine ope rating conditions.
lWhen a misfire is detected, the PCM stores a diagnostic trouble code and causes the to either flash or illuminate continuously during active misfire.
Range of Check
l MAP voltage is less than 1.60
l Engine speed is between 2200 and 2800 l Engine coolant temperature is greater than l Vehicle speed less than Set Condition
l 1000 Rev Misfire
The PCM detects misfire in more than 1.6% of the en gine cycles in a 1000 revolution
period.l 200 Rev MisfireThe PCM detects misfire in more than 15% of the eng ine cycles in a 200 revolution period.
.
Spark plugs or wires failed
l Ignition coil failed
l Crankshaft position piston rings v a l v e s
l Head gasket failed
l C r a c k e d
l Fuel lines and filter failed
l Fuel failed
l failed
l Wiring and connectors failed
l Engine coolant
l Timing belt tooth broken,
l EGR
SCAN TOOL SENSOR READ TESTS (Data list)
05 Engine coolant temperature sensor (Refer to Check the engine coolant temperature circuit.
(Refer to INSPECTION PROCEDURE 38.)
OK
SCAN TOOL SENSOR READ TESTS (Data list)
27 Intake air temperature sensor (Refer to
OK
Check the intake air temperaturecircuit.(Refer to INSPECTION PROCEDURE
SCAN TOOL SENSOR READ TESTS (Data list)
11 MAP sensor reading (Refer to
OK
OK
Check the MAP sensor circuit.(Refer to INSPECTION PROCEDURE 40.)
SCAN TOOL SENSOR READ TESTS (Data list)
Check the following connectors: 66 Oxygen sensor volts (front) (Refer to OK: Repeat and alternately whenidling.
Check the fuel pressure. (Refer to Check the harness wire between the PCM and the cran kshaft
position sensor connector.
l Check the injectors for operation sound.
l Check the injectors for fuel leakage.
l Check the evaporative emission control system.
Check the following items.
l Check the ignition coil, spark plug cables.
l Check the compression pressure.
Check the EGR
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E N G I N E
Scan tool
Cylinder Misfire
Code General scan tool Cylinder Misfire
No.Cylinder MisfireProbable cause
Cylinder Misfire
43,
[Comment]
Backgroundl Spark plugs or ,
l Excessive engine misfire results in increased catal yst temperature.l l . valves
l Severe misfire could cause catalyst damage.
l To prevent catalytic converter damage, the PCM moni tors engine’ misfire.l
H e a d g a s k e t f a i l e d
l The PCM monitors for misfire during most engine ope rating conditions., h e a d
When a misfire is detected, the PCM stores a diagno
stic trouble code and causes thel
Injector failedl to either flash or illuminate continuously during active misfire.
Range of Check
l MAP voltage is less than
l Engine speed is between 2200 and l Engine coolant temperature is greater than l Vehicle speed less than Set Conditionl 1000 Rev Misfire l
Wiring harness and connectors failed
6
The PCM detects misfire in more than 1.6% of the en gine cycles in a 1000 revolutionperiod. 200 Rev MisfireThe PCM detects misfire in more than 15% of the eng ine cycles in a revolution period.
NG
OK
OK
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Check the following items.
l Check the spark plug, spark plug cables.
l Check compression pressure.
l Check the cylinder head gasket and intake manifold gasket for damage.

ENGINE Troubleshooting
INSPECTION PROCEDURE 4
The check engine/malfunction indicator lamp remains
illuminated and never goes out.
[Comment]In cases such as the above, the cause is probably t hat the PCM is
detecting a problem in a sensor or actuator, or tha t one of the malfunctions listed at right has
occurred.
Probable cause
l Short-circuit between the check indicator lamp and l Malfunction of the PCM
SCAN TOOL DTC Refer to
INSPECTION CHART FOR DIAGNOSTIC
Are diagnostic trouble codesoutput? TROUBLE CODES
Measure at the combination meter connector lDisconnect the connector, and measure at the harnes s
side.Check the harness wire between meter and PCM
connector. Repair, if necessary.
l Disconnect the PCM connector.
l Continuity between 51 and ground
OK: No continuity
O K
Replace the PCM.
INSPECTION PROCEDURE 5
Cranks, won’t start Probable cause
[Comment]l Malfunction of the ignition system
In cases such as the above, the cause is probably t hat a spark plugs are fouled defective,l Malfunction of the fuel pump system
or that the supply of fuel to the combustion chambe r is defective.
l Malfunction of the injector system
in addition, foreign materials (water, kerosene, et c.) may be mixed with the fuel.
l Malfunction of the PCM
l Foreign materials in fuel
,
Check battery positiv
OK: 8 or hiaher Check the battery. (Refer to GROUP 54 Battery)
OK
Scan tool: Inspection when no initial combustion oc
curs.
(Refer to INSPECTION PROCEDURE 29.)
OK
Can any sound be heard
.
(Refer to
Yes
Check ignition circuit system.
(Refer to INSPECTION PROCEDURE 28.)
OK
Check the injector control circuit. Carry out proce dures 19, 20, 21, in “INSPECTION PROCEDURE
FOR DIAGNOSTIC TROUBLE CODES”.,
Check the following items. l Check the ignition coil, spark plugs, spark plug ca bles.
l Clean the injectors.
l Check if foreign materials (water, alcohol, etc.) g ot into fuel.
l Check the compression pressure.
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ENGINE (NON-TURBO)=,
INSPECTION PROCEDURE 6
Fires up and dies.P r o b a b l e
[Comment]l of the ignition system
In such cases as the above, the cause is probably t hat the spark plugs are generating sparkslbut the sparks are weak, or the initial mixture for starting is not appropriate.Malfunction of the injector system
l Foreign fuel
l Poor compression
l
of the PCM
Check the battery. (Refer to GROUP 54
OK:8 or higher
Scan tool: Inspection when incomplete combustion oc curs.(Refer to INSPECTION PROCEDURE 30.)
OK
Canany sound be heard (Refer to
Yes
Check the injector control circuit. Carry out procedures in “INSPECTION PROCEDURE
FOR DIAGNOSTIC TROUBLE CODES”.
Is starting good if the engine is cranked with the acceleratorpedal slightly depressed?
No
motor circuit INSPECTION
PROCEDURE FOR
TROUBLECODE
Check the following items.
l Check the ignition coil, spark plugs, spark plug ca bles.
l Clean the injectors.
l Check the compression pressure.
l Check fuel lines for
l Check if foreign (water, alcohol, etc.) got into fuel.
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INSPECTION PROCEDURE 7
Hard startingIProbable cause I
[Comment]l Malfunction of the ignition systemIn cases such as the above, the cause is probably t hat the spark is weak and ignition is difficult,lMalfunction of the injector system
the initial mixture for starting is not appropriate , or sufficient compression pressure is not beinglInappropriate gasoline useobtained.l P o o r
Check battery positive vo
OK: 8 or higherOK
Scan tool: Inspection when incomplete combustion oc curs.
(Refer to INSPECTION PROCEDURE 30.)Check the battery. (Refer to GROUP 54
Battery)1
Can any sound be heard fro
No Check the injector control circuit. Carry out proc
edures 19, 20, 21,
(Refer to in “INSPECTION PROCEDURE
YesFOR DIAGNOSTIC TROUBLE CODES”.
Check the following items.
l Check the ignition coil, spark plugs, spark plug ca bles.
l Clean the
l Check the pressure.
l Check if foreign materials (water, alcohol, etc.) g ot into fuel.

ENGINE (NON-TURBO)> Troubleshooting
INSPECTION PROCEDURE 8
Unstable idle (Rough idle, hunting)Probable cause
[Comment] Malfunction of the ignition system
In cases such as the above, the cause is probably t hat the ignition system,l Malfunction of air-fuel ratio system
idle air control motor or compression pressure is d efective.
l Malfunction of the system
Because the range of possible causes is broad, insp ection is narrowed down to simple items.
l Malfunction of the evaporative emission
purge solenoid system
l Malfunction of the EGR system
l Poor compression
l Drawing air into exhaust system
W ere the battery terminals disconnected recently?
SCAN TOOL DTC
Are diagnostic trouble codes output
NO Refer to
INSPECTION CHART FOR DIAGNOSTICTROUBLE CODES.
YES
Inspection when hunting occurs.
(Refer to INSPECTION PROCEDURE 31.)
SCANTOOL Actuator test
07 motor (Refer to
OK
NG Check the idle air control motor (Refer to P. INSPECTION PROCEDURE FOR DIAGNOSTIC TROUBLE CODE
SCAN TOOL Specialfunction
“Reset
I
Check trouble symptoms.
OK
Scan tool: Inspection when idle speed is unstable. (Refer
to INSPECTION PROCEDURE 32.)
OK
Check the injector control circuit: (Carry out pro cedures 19, 20, 21, in “INSPECTION PROCEDURE
FOR DIAGNOSTIC TROUBLE CODES”.)
Check the following items. l Check the ignition coil, spark plugs, spark plug ca bles.
l Check the purge control system.
l Check the EGR svstem.
l Check the compression pressure.
l Check if foreign materials (water, alcohol, etc.) g ot into fuel.
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ENGINE,
INSPECTION PROCEDURE 11When the engine is cold, it stalls at idle. (Die ou t)
[Comment]lMalfunction of the idle air control
In such cases as the above, the cause is probably t hat the air/fuel mixture is inappropriate when l Malfunction of the fhroffle body the engine is cold, or that the intake air volume i s insufficient..l Malfunction of the injector System l Malfunction: system
W ere the battery terminals disconnected recently?
NO
SCAN TOOL DTC
.After warming-up, let the engine run at idling for 10 minutes.I
,
Are diagnostic trouble codes output?TROUBLE CODES
N OI -.: .
Does the engine stall right after the accelerator p
edal is
Check the throffle body minimum air (Refer to released
NO . . . N O Check for unstable idle (Rough hunting)Is engine-idling stable after the warming-up?
YES(Refer to INSPECTION 8.)
SCAN TOOL Actuator test
07 motor (Refer to
OK NG
Check the idle air control motor circuit. (Refer t
o INSPECTION PROCEDURE FOR TROUBLE CODE
SCAN TOOL Special function
“Reset
Check trouble symptoms.
NG
OK
.
Check the injector control circuit. Carry procedures 19, in “INSPECTION PROCEDUREFOR DIAGNOSTIC TROUBLE
Check the fuel pressure. (Refer to
Check the following items.
l Check the ignition coil, spark plugs, spark plug ca bles.
l Check the compression pressure.
l Check the engine oil viscosity.
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E N G I N E
INSPECTION PROCEDURE 12 , .
. .
When the engine is hot, it stalls at idle. (Die out )
[Comment]l Malfunction of the ignition In cases such as the above, the cause is probably t hat ignition system, mixture, idle l
air control motor or compression pressure is defect ive.Malfunction control M a l f u n c t i o n o f t h e s y s t e m In addition, if the engine stalls, the cause
mayalso be a defective connector contact.l into intake system
l Improper connector contact
W ere the battery terminals disconnected recently
NO
YES After warming-up, let the engine run at idling for 10 minutes.
SCAN TOOL DTC
Are diagnostic trouble codes output?
NO
SCAN TOOL Actuator test
07 motor. (Refer to
OK YES
N G
Refer to INSPECTION CHART FOR DIAGNOSTICTROUBLE CODES.
Checktheidleaircontrolmotorcircuit. INSPECTIONPROCEDURE FOR DIAGNOSTIC TROUBLE CODE
SCAN TOOL Special function
“Reset
Check trouble symptoms.
NG
Check the injector for operation sound.
(Refer to Check the injector control circuit. Carry out proc edures 20, in “INSPECTION PROCEDURE
FOR DIAGNOSTIC TROUBLE CODES”.
Does the engine stall right
released
NO.
Does the engine stall easily again
YES
Scan tool: Inspection when engine stalls when the e ngine
is warm and idling (Refer to INSPECTIONPROCEDURE 33.)
OK
Check the throttle body minimum air flow (Refer to
While carrying out an intermittent malfunction simulation test (Refer
to GROUP 00 How to Cope with Intermittent Malfunctions), check
for sudden changes in the signals shown below.
l Crankshaft position sensor and
l MAP sensor signal Fuel pump signall Injector drive signal l power supply voltage
Check the following items.
l
Check the ignition coil, spark plugs, spark plug ca bles.
l Clean the injectors.
l Check the compression pressure.
l Check if foreign materials (water, alcohol, etc.) g ot into fuel.
INSPECTION PROCEDURE 13
The engine stalls when accelerating. (Pass out) Probable cause
[Comment]l
Injectors failedIn cases such as the above, the cause is probably m isfiring due to a weak spark, or an inappropriatelMalfunction of the ignition system
air/fuel mixture when the accelerator is depressed.
YESRefer to INSPECTION CHART FORDIAGNOSTIC
Arediagnostic trouble codes outputTROUBLE CODES.
NO
Check the following items.
l Check the ignition coil, spark plugs, spark plug ca bles.
l Clogged injectors

ENGINE (NON-TURBO)>
INSPECTION PROCEDURE 14. .. .
The engine stalls when decelerating.P r o b a b l e c a u s e
[Comment]In cases such as the above, the cause is probably t
hat the intake air volume is insufficient due
to a defective idle air control motor system. l Malfunction of the system
W ere the battery terminals disconnected recently?YES After warming-up, let the engine run at idling for
SCAN TOOL DTC
Are diagnostic trouble codes output?
OK
Refer to I N S P E C T I O N FOR TROUBLE CODES.. .
SCAN TOOL SENSOR07 Throttle position (Refer to
NO
NGCheck the throttle position sensor circuit.
(Refer to INSPECTION PROCEDURE 43.)
Check the following items. l Check the ignition coil, spark plugs, spark plug ca bles.
l Check the throttle body minimum air flow.
INSPECTION PROCEDURE 15
Hesitation, sag or stumble
[Comment]In cases such as the above, the cause is probably t hat ignition system, air/fuel mixture or
compression pressure is defective.
Probable cause
Malfunction of the ignition Malfunction of air-fuel ratio control l Malfunction of the fuel supply l of the EGR. solenoid l P o o r
Are diagnostic trouble
codes output
Check the injectors for opNG
(Refer to Check the injector control circuit. out procedures 20, 21, in’ INSPECTION PROCEDUREFOR DIAGNOSTIC TROUBLE CODES”.
Scan Tool: Inspection when hesitation, sag, stumble or pooracceleration occur. (Refer to INSPECTIONPROCEDURE 34.)
OK
Check the fuel pressure. (Refer to
OK
Check the following items.l Check the ignition coil, spark plugs, spark plug ca bles.
l Check the EGR system.
l Check the compression pressure.
l Check the fuel filter or fuel line for clogging.
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