Hyundai Accent Quiz
Ignition System

Spark Plug Reading

In this manual: Ignition System
Owner's Manual — 155SOHC Engines — 75DOHC Engines — 49Lubrication System — 14Cooling System — 23Emission Control — 3PCV Valve — 5Fuel system — 44Ignition System — 12Clutch — 17Manual transmission — 14Automatic transmission — 24Axle Shafts and Drive Shafts — 17Suspension — 31Steering — 45Brake System — 39Body — 23Air Conditioning System — 32Electrical Equipment — 54Appendix — 9Wiring Diagrams — 3
~1min read

Visual inspection of the spark plug firing end can indicate the condition of the engine.

If the insulator nose is covered with black deposits, the mixture is too rich. If the deposits are black and oily, this indicates engine wear and the engine should be inspected and repaired. If the insulator nose is covered with light brown deposits, the mixture is optimal and the engine is in good condition.

If the insulator nose of the spark plug is clean and white, without deposits, this indicates a mixture that is too lean. It also indicates that the plug is too hot, meaning heat is dissipated slowly from the center electrode. In this case, adjust the fuel mixture or replace the spark plug.

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