Check spark plugs

Manually remove the tips of high-voltage wires from spark plugs.

Remove the spark plug wrench. To avoid damaging the spark candle key place strictly along the axis of the candle. If you must make a reversing candle excessive force, do not remove the candle, as you can damage the threads in the cylinder head. Warm up the engine - should be easy to turn out candles.

Connect to a high-voltage spark plug wire. Hold the spark plug special pliers with insulated handles, connect the plug body to "weight" of the car.

Rotate the crankshaft of the engine starter, the spark between the electrodes should be observed sustained strong spark.

Check out all of the spark plug for the following damages:

- Failure of the insulator 1 (Fig. 2.133);

- The wear of the electrode 2;

- 3 carbon deposits;

- Damaged or dilapidated gasket 4;

- The state of porcelain insulator at the tip of the spark plug 3.

Check the electrode gap of the spark plug.

Replace the spark plug and tighten it to the required torque. When installing do not

cold screw the spark plug in the hot cylinder head, because in the future they will not be able to turn out.

To facilitate screwing and reversing of spark plugs put on a carving candles thin layer of soft graphite pencil or plastic lubricant based on copper. If you use the engine oil, the candle will burn to the head unit and it will not be able to turn out.

The tightening torque of the spark plug - 20-30 Nm.

Electrode gap of spark plugs

Spark plug electrode gap is important because if too much and too small a size of a spark gap is changed, resulting in reduced engine performance. The gap must always conform to the specifications.

During the combustion of fuel-air mixture slightly electrodes candles burn. This contributes to the spark that kicks particles of metal from the electrodes, so that the electrode gap increases with the duration of operation of spark plugs.

For a breakdown too electrode gap requires a high voltage, which can cause misfiring or engine start up is impossible. Therefore, you must promptly check and adjust the gap (Fig. 2.134).

Backlash check or wire template probe and adjust podgibaniem side electrode. The gap should be in the range 1.0-1.1 mm.

Diagnosis of engine appearance of spark plugs

On appearance of the spark plugs can be roughly judge the state of the engine, deviations in his work on the optimal parameters. Testing should be done after a thorough warm up the engine of the car on speed highway. Check after the trip a short distance can lead to erroneous results. During the test, inspect the upper part of the cone of thermal insulator with a central electrode and the ground electrode.

Light gray or brown cone insulator

- It indicates that the fuel injection and ignition are functioning properly, ensuring efficient operation of the engine.

Large deposits

- Indicate the use of non-conforming manufacturer's brands of motor oil or fuel. If possible, replace the brand of motor fuel and, therefore, oil.

Large deposits of soot

- There is the case where the motor is often used for short journeys and warms to normal operating temperature, the temperature of combustion does not correspond to the temperature at which increases the content of carbon monoxide.

White cone insulator

- It indicates that the engine is operating with too much ignition timing (pre-ignition), which is typical for violations adjust the ignition timing and the knock sensor operation.

Melting of the central and lateral electrodes

- Shows that the heat rating of the spark plug is not correct, adjust the disrupted functioning of the ignition timing and the knock sensor or disrupted operation of the cooling system.

The destruction of the top of the cone insulator

- It indicates that the fuel-air mixture burns with a detonation due to violation of adjusting the angle of the ignition timing, the functioning of the knock sensor, mode of operation of the cooling system or the depletion of fuel-air mixture due to possible air leaks.

Plaque yellow color on top of the cone insulator

- Appears when the burn-additive in the fuel or engine oil. They melt at the engine maximum load, forming a conductive layer, whereby the misfire may occur. After a large number of short journeys is not recommended to immediately operate the engine with maximum power.

A layer of oil on the cone of the insulator and the electrodes

- Deposited with the wear of piston rings, valve guides and valve stem seals.

If the appearance of the spark plug without deviation, but the operation of the engine is broken, possibly defective spark. Invisible cracks in the facility at the start of the cold engine can be filled with fuel that removes spark. Furthermore, pressure may be impaired sparking, despite the fact that the outdoor plug is normal.