Testing and checking

TESTING AND CHECKING

• Check whether the ignition coil features are those prescribed. If not, replace the coils.

SPARK PLUGS

The spark plugs fitted in this vehicle are surface discharge spark plugs with central point and electrode.

The electrode distance must be respected in order for this type of spark plug to work.

The spark plugs are located in the combustion chamber asymmetrically. Their sizes are different, as can be seen in the following illustration.

Firing order

CHECKING AND REPLACING

• When the engine is cold, remove the ignition coils (see specific paragraph).

1. Unscrew and remove the spark plugs after blowing air in the respective seats to remove dirt and debris.

• Check the ceramic insulator is clean and not cracked. If it is, replace the spark plugs.

IMPORTANT: The use of spark plugs with different features or dimensions can severely damage the engine and alter the level of pollutants in exhaust.

IMPORTANT: A dirty or burnt spark plug is often the symptom of faulty engine fuel feeding.
• Traces of dust and soot: incorrect mixture, air cleaner very dirty;
• Oil stains: oil leaking from gas rings;
• Ash forming: presence of aluminium material contained especially in the oil;
• Fused electrodes: overheating due to unsuitable fuel, faulty valves;
• High electrode wear: harmful additives in fuel or oil, engine knocking, overheating;
• Etc.

• To refit, torque the spark plugs as follows:

Central spark plugs (large - M14) 25 ÷ 35 Nm
2.6 ÷ 3.6 kgm

Side spark plugs (small - M10) 10 ÷ 12 Nm
1.0 ÷ 1.2 kgm