E.C.C. Trouble Diagnoses (Models with catalyzer) - How to Perform Trouble Diagnoses for Quick and Accurate Repair (Cont'd) - Intermittent Problem Simulation
EF & EC-47prose procedureApplies to GA13DS, GA14DS & GA16DS engines with catalyzer.
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
1
Variable factorAir-fuel ratio
Influential partAir-fuel ratio solenoid
Target conditionMade lean
Service procedureSupply it with battery voltage.
1
Variable factorAir-fuel ratio
Influential partAir-fuel ratio solenoid
Target conditionMade rich
Service procedureDisconnect carburetor harness connector (F8).
2
Variable factorIgnition timing
Influential partDistributor
Target conditionAdvanced
Service procedureRotate distributor counterclockwise.
2
Variable factorIgnition timing
Influential partDistributor
Target conditionRetarded
Service procedureRotate distributor clockwise.
3
Variable factorAir-fuel ratio feedback control
Influential partExhaust gas sensor
Target conditionSuspended
Service procedureDisconnect exhaust gas sensor harness connector.
3
Variable factorAir-fuel ratio feedback control
Influential partControl unit
Target conditionOperation check
Service procedureRefer to "Checking Exhaust Gas Sensor" in MA section.
4
Variable factorIdle speed
Influential partCarburetor
Target conditionRaised
Service procedureTurn throttle adjusting screw clockwise.
4
Variable factorIdle speed
Influential partCarburetor
Target conditionLowered
Service procedureTurn throttle adjusting screw counterclockwise.
5
Variable factorElectric connection (Electric continuity)
Influential partHarness connectors and wires
Target conditionPoor electric connection or faulty wiring
Service procedureTap or wiggle. Race 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 headlamps, air conditioner, rear defogger, etc.
9
Variable factorThrottle valve switch condition
Influential partControl unit
Target conditionON-OFF switching
Service procedurePush throttle valve switch.
10
Variable factorIgnition spark
Influential partTiming light
Target conditionSpark power check
Service procedureTry to flash timing light for each cylinder.