TROUBLE DIAGNOSES — How to Perform Trouble Diagnoses for Quick and Accurate Repair (Cont'd) — INTERMITTENT PROBLEM SIMULATION
EF & EC-37spec tableRow 3 (marked with *) applies to catalyzer model only.
How to Perform Trouble Diagnoses for Quick and Accurate Repair (Cont'd)
INTERMITTENT PROBLEM SIMULATION
In order to duplicate an intermittent problem, it is effective to create similar conditions for component parts, under which the problem might occur.
Perform the activity listed under Service procedure and note the result.
Intermittent Problem Simulation — Variable Factors, Influential Parts, Target Conditions and Service Procedures
| Variable factor | Influential part | Target condition | Service procedure | |
|---|---|---|---|---|
| 1 | Mixture ratio | Pressure regulator | Made lean | Remove vacuum hose and apply vacuum. |
| 1 | Mixture ratio | Pressure regulator | Made rich | Remove vacuum hose and apply pressure. |
| 2 | Ignition timing | Crank angle sensor | Advanced | Rotate crank angle sensor counterclockwise. |
| 2 | Ignition timing | Crank angle sensor | Retarded | Rotate crank angle sensor clockwise. |
| 3* | Mixture ratio feedback control | Exhaust gas sensor | Suspended | Disconnect exhaust gas sensor harness connector. |
| 3* | Mixture ratio feedback control | Control unit | Operation check | Perform self-diagnosis (Mode I/II) at 2,000 rpm. |
| 4 | Idle speed | I.A.A. unit | Raised | Turn idle adjust screw counterclockwise. |
| 4 | Idle speed | I.A.A. unit | Lowered | Turn idle adjust screw clockwise. |
| 5 | Electric connection (Electric continuity) | Harness connectors and wires | Poor electric connection or faulty wiring | Tap or wiggle. |
| 5 | Electric connection (Electric continuity) | Harness connectors and wires | Poor electric connection or faulty wiring | Race engine rapidly. See if the torque reaction of the engine unit causes electric breaks. |
| 6 | Temperature | Control unit | Cooled | Cool with an icing spray or similar device. |
| 6 | Temperature | Control unit | Warmed | Heat with a hair drier. [WARNING: Do not overheat the unit.] |
| 7 | Moisture | Electric parts | Damp | Wet [WARNING: Do not directly pour water on components. Use a mist sprayer.] |
| 8 | Electric loads | Load switches | Loaded | Turn on head lights, air conditioner, rear defogger, etc. |
| 9 | Idle switch condition | Control unit | ON-OFF switching | Perform self-diagnosis (Mode IV). |
| 10 | Ignition spark | Timing light | Spark power check | Try to flash timing light for each cylinder. |
1
Variable factorMixture ratio
Influential partPressure regulator
Target conditionMade lean
Service procedureRemove vacuum hose and apply vacuum.
1
Variable factorMixture ratio
Influential partPressure regulator
Target conditionMade rich
Service procedureRemove vacuum hose and apply pressure.
2
Variable factorIgnition timing
Influential partCrank angle sensor
Target conditionAdvanced
Service procedureRotate crank angle sensor counterclockwise.
2
Variable factorIgnition timing
Influential partCrank angle sensor
Target conditionRetarded
Service procedureRotate crank angle sensor clockwise.
3*
Variable factorMixture ratio feedback control
Influential partExhaust gas sensor
Target conditionSuspended
Service procedureDisconnect exhaust gas sensor harness connector.
3*
Variable factorMixture ratio feedback control
Influential partControl unit
Target conditionOperation check
Service procedurePerform self-diagnosis (Mode I/II) at 2,000 rpm.
4
Variable factorIdle speed
Influential partI.A.A. unit
Target conditionRaised
Service procedureTurn idle adjust screw counterclockwise.
4
Variable factorIdle speed
Influential partI.A.A. unit
Target conditionLowered
Service procedureTurn idle adjust screw clockwise.
5
Variable factorElectric connection (Electric continuity)
Influential partHarness connectors and wires
Target conditionPoor electric connection or faulty wiring
Service procedureTap or wiggle.
5
Variable factorElectric connection (Electric continuity)
Influential partHarness connectors and wires
Target conditionPoor electric connection or faulty wiring
Service procedureRace engine rapidly. See if the torque reaction of the engine unit causes electric breaks.
6
Variable factorTemperature
Influential partControl unit
Target conditionCooled
Service procedureCool with an icing spray or similar device.
6
Variable factorTemperature
Influential partControl unit
Target conditionWarmed
Service procedureHeat with a hair drier. [WARNING: Do not overheat the unit.]
7
Variable factorMoisture
Influential partElectric parts
Target conditionDamp
Service procedureWet [WARNING: Do not directly pour water on components. Use a mist sprayer.]
8
Variable factorElectric loads
Influential partLoad switches
Target conditionLoaded
Service procedureTurn on head lights, air conditioner, rear defogger, etc.
9
Variable factorIdle switch condition
Influential partControl unit
Target conditionON-OFF switching
Service procedurePerform self-diagnosis (Mode IV).
10
Variable factorIgnition spark
Influential partTiming light
Target conditionSpark power check
Service procedureTry to flash timing light for each cylinder.
NOTE
*For catalyzer model