Attention! We recommend that you do not manually clean a removed spark plug. This damages the insulating layer of the central electrode of the spark plug.
You can independently check the gap between the electrodes of the candle.
1. Remove tips of high-voltage wires from spark plugs.
2. Turn out candles and lay them in accordance with the order of operation of the cylinders. A subsequent inspection of the spark plugs will allow you to draw certain conclusions regarding the corresponding cylinder.
3. Don't use too much force if the spark plugs can't be removed. The threads of the spark plug hole may be damaged.
4. Warm up the engine and remove the spark plugs.
Attention! Do not install cold spark plugs on a hot engine. Later they will not be able to turn out, because. in this case, they will be planted as if on rivets.
5. Tighten the spark plugs during installation with a torque of 20 Nm. If it is not possible to use a torque wrench when installing candles, then follow the following rule to install the candles correctly.
6. Screw in the spark plug until the O-ring fits against the surface of the cylinder head.
Further tightening of the candle is impossible without the application of a certain effort. In this position, tighten the new spark plug about a quarter of a turn, and the used spark plug by turning the wrench about 15°.
Attention! To make the candles turn out easily, apply a little graphite to their threads by crushing the pencil stem, or grease it with a thin layer of copper grease. Lubricating the threads of the candles with ordinary grease or oil only worsens the situation. Candles in this case stick to the thread.
If the thread in the hole for the candle is broken, then the workshops in this case use the corresponding threaded sleeve, which is inserted into the candle socket.
The condition and appearance of the spark plugs can tell a lot about the performance of the engine. If the candles are removed for this purpose, then the engine should first be warmed up, having traveled a sufficiently long distance. Inspect the spark plug, paying special attention to the center electrode insulator and ground electrodes.
- A) gray or brownish center electrode insulator. The fuel injection system is well adjusted and the engine runs economically.
- b) sediment layer. The reason for this may be additives to engine oil or fuel, as well as increased oil consumption. You can change the type of oil or fuel.
- V) black sooty deposits. Due to the vehicle being used for short trips, the spark plugs do not reach the self-cleaning temperature. Incorrect glow plug value.
- G) white insulator. Too early ignition timing. Electronic ignition control or knock sensor not working.
- d) melting of the central and side electrodes. Pre-ignition due to deposits in the combustion chamber. overheating of injectors, incorrectly set ignition timing, faulty electronic ignition control, defective knock sensor or overheating due to insufficient cooling.
- and) breakage of the insulator. At the initial stage, it manifests itself in the form of microscopic cracks. The result of knocking combustion due to refueling with low-quality fuel, incorrectly set ignition timing, incorrect ignition control, defective knock sensor, insufficient cooling or lean mixture due to «suction» air.
- h) oil film on the electrodes and on the candle. Worn piston rings, valve stems or valve stem seals.
If the candle is outwardly normal, but the engine starts with difficulty, jerkily, then the reason for this may still be candles. Cracks in the ceramic insulator that are invisible during inspection of the spark plugs can be filled with fuel condensate when starting a cold engine and the spark discharge can be discharged in a different direction. The candle may not fire as a result of the pressure generated, although it produces a spark when removed.
Nominal values of the gap between the electrodes of the spark plugs:
- four- and five-cylinder engines: 0.7-0.9 mm;
- six-cylinder engine: 0.9-1.1 mm.
Spark at spark plugs with three side electrodes used on AUDI 80 vehicles, «seeks out» electrode with a minimum gap. For this reason, bending the electrode is practically not necessary.
There are several factors to consider when choosing spark plugs:
1) Heat number. Installed candles must correspond to the temperatures that occur in the combustion chamber. The glow number is the temperature value that the candle is able to withstand.
2) Electrodes. On AUDI 80 cars, spark plugs with three side electrodes are installed.
3) Candle carving. The spark plug thread for vehicles A UDI80 must be 19 mm. Thread diameter - 14 mm.
4) The size of the hexagon on a turnkey candle. For spark plugs installed on cars with 4- and 5-cylinder engines, the hex width is 20.8 mm, and for six-cylinder engines - 16 mm.
5) Seal. The car manufacturer AUDI 80 recommends flat seal spark plugs for all models. On such candles, a non-removable sealing ring is installed.
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