Service manual

G420F(FE) Service Manual Chapter 2. Recommended Maintenance 25
Ignition System Maintenance
Inspect Battery System
• Clean battery outer surfaces with a mixture of
baking soda and water.
• Inspect battery outer surfaces for damage and
replace as necessary.
• Remove battery cables and clean, repair and/or
replace as necessary.
Inspect Ignition System
• Remove and inspect the spark plugs. Replace as
required.
• Inspect the ignition coil for cracks and heat
deterioration. Visually inspect the coil heat sink
fins. If any fins are broken replace as required.
Inspection of Ignition Timing
1. Inspection condition
Coolant temperature : 80-90°C(At normal
Temperature)
Lamp and all accessories : OFF
Transmission : In neutral position
Parking brake : ON
2. Inspection
1) Connect the timing light.
2) Measure RPM.
RPM
Low Idle 750±15rpm
NOTE: If RPM is not normal, it is impossible to
measure the proper ignition timing, so measure it at
a normal RPM.
3) Inspect the standard ignition timing.
BTDC 5˚±5˚
4) If ignition timing is out of the standard, inspect
sensors concerned with ignition timing.
CAUTION
Because ignition timing is fixed by set data
value in ECU, it is impossible to control on
purpose.
Fist, check that sensors send output properly to
help determine ignition timing control.
NOTE: Affective ECU input to lgnition timing control
• Coolant temperature sensor
• Oxygen sensor
• Battery voltage
• MAP sensor (Engine load)
• Crankshaft position sensor
• Throttle position sensor
• Intake Air Temperature sensor
5) Check that actual ignition timing is changed
with engine RPM increased.