Pic. 2.30. Removing a tip with a high-voltage wire from a spark plug on cars before 2001
On cars before 2001, pull up and turn at the same time, remove the tip with the high-voltage wire from the spark plug (pic. 2.30). In order not to mix up the wires to the spark plugs, replace the spark plugs one by one.
On vehicles since 2001, remove the ignition coils.
Clean the area around the spark plug with a jet of compressed air to prevent dirt from entering the engine cylinder after the spark plug is removed.
Remove the spark plug.
If replacement of spark plugs is necessary, use only spark plugs recommended for this engine.
Examine the spark plugs. By their appearance, you can determine the condition of the engine. A clean, white, non-tarnished spark plug insulator indicates a too lean air-fuel mixture. It may also indicate that the candle is too «hot» type (heat is removed from the central electrode slowly). It is necessary to adjust the composition of the air-fuel mixture or install a spark plug that is suitable for the characteristics of this engine.
The deposition of dry black soot indicates too rich a mixture.
If the coating is black, oily, then the engine is worn out, it must be checked and repaired.
If the insulator is covered with a light brown coating, then the mixture is optimal and the engine is in good condition.
Attention! Since 2001, cars have been using spark plugs with electrodes coated with iridium. On such candles, the electrode gap is not adjustable.
Too large and too small an interelectrode gap, at which the power of the spark changes, leads to a decrease in the efficiency of the engine. The gap must always comply with the technical requirements.
Pic. 2.31. Checking the gap between the electrodes of the spark plug
Check the gap with a wire gauge or feeler gauge (pic. 2.31). You can adjust the gap by bending the side electrode with a special tool (pic. 2.32).
Pic. 2.32. Correction of the spark plug gap by bending the side electrode with a special tool
Before installing the spark plug in the engine, check that the threads are clean and undamaged. Clean the thread if necessary. Apply a special non-stick compound to the thread of the candle.
Inspect spark plugs for defects. If there are cracks in the insulator, replace the spark plug.
To wrap the spark plug for the first few turns, use a piece of rubber hose into which, on one side, insert the spark plug insulator. The hose acts as a universal joint to align the spark plug with the threaded hole. If the spark plug is screwed in misaligned, the hose will rotate on the spark plug insulator, preventing damage to the threads. Wrap the spark plug a few turns of thread, remove the hose and then wrap and tighten the spark plug with a wrench.
On cars up to 2001, reinstall the tip with the high-voltage wire by pressing it and turning it at the same time until it is clearly fixed.
Note. Recommended interval: every 50,000 km or 24 months.
Note. The cover and rotor of the ignition distributor are equipped with cars only up to 1997 of release. Cars produced from 1988 to 2000 are equipped with a contactless ignition system.
Note. Cars produced before 2001 have high-voltage wires, and since 2001, ignition coils are installed directly on the spark plugs.
On vehicles from 2001, install ignition coils.
Replace the rest of the spark plugs in the same way.