In the electronic ignition system, a very high voltage is generated! Be careful, observe all necessary precautions when servicing any system components, including not only the main (ignition module, coil and BB wires), but also related, such as candle connectors, a tachometer and other equipment. Persons with an implanted pacemaker must not be allowed to service the components of the ignition system!
Tools needed when changing spark plugs
1 - candle head - Equipped with a special elastic insert, which excludes the possibility of accidental damage to the porcelain insulator when the candle is turned inside out.
2 - torque wrench - Not one of the mandatory tools, it provides a reliable guarantee of the correct tightening torque of the spark plugs.
3 - Ratchet drive - It is used in a set with a candle head and a torque wrench.
4 - Extension - Depending on the model and its accessories, access to the spark plugs may be limited to varying degrees, so the use of extensions of the appropriate shape and design will greatly facilitate the procedure.
5 - Tool for measuring and correcting spark plug gaps - There are several types of this type of tool available - make sure the tool is equipped with a feeler gauge that matches the size of your car's spark plug gaps.
Checking the condition and maintenance of spark plugs
On Z20LET engines, the spark plugs are replaced every 30,000 km.
The correct functioning of the spark plugs is largely determined by the efficiency of the engine output. It is important that the correct type of spark plug is installed on the engine (see Specifications). The need for unscheduled maintenance of spark plugs is extremely rare, provided that the engine itself is in good condition. To avoid accidental damage to the electrodes, do not clean the candles without the use of special equipment.
In most cases, a special spark plug head is required to replace spark plugs (with elastic lining inside) complete with ratchet drive, as well as a set (see illustration Tools needed when changing spark plugs). A special tool is also available for safely disconnecting the BB wire tips from the spark plug shanks, although its use is not strictly required. Using a torque wrench will allow you to achieve the correct tightening torque for the candles.
1. On 1.4, 1.6 and 1.8L DOHC models remove the oil filler cap, unscrew the fixing screws and remove the engine protection cover. Reinstall the oil filler cap.
2. On 2.0 l models unscrew the fixing screws and remove the protective cover of the candles from the cover of the gas distribution mechanism.
3. On 1.6L SOHC and 2.0L models, if the marking of high-voltage wires is not visible, apply it. Disconnect the explosive from the spark plugs - pull on the tip, not on the wire itself.
4. On 1.6L SOHC, 1.4 and 1.8L DOHC models the ignition module is installed between the camshaft housings, directly above the spark plugs - disconnect the electrical wiring from it. Turn out fixing screws and remove the module of ignition from a head of cylinders. If the module does not come off, screw a couple of long M8 bolts into its threaded holes and try using them as handles.
5. The spark plugs on some of the models in question are deeply recessed into the candle niches, so you will need a key drive extension to turn them out. Putting the head on the candle, connect the drive and, gently turning the collar counterclockwise, unscrew the candle.
1 - Crank with ratchet drive
2 - Extension
3 - cardan joint
4 - Candle head with elastic insert
5 - spark plug
6. Check the removed spark plug against the condition map shown in the photographic insert to give a good idea of the overall condition of the engine.
7. Checking the condition of the spark plugs gives a good indication of the condition of the engine. If there are no traces of any deposits on the insulator of the central electrode, this indicates that the air-fuel mixture is too lean, or that an excessive candle is used (heat removal from the insulator to the body on candles is much less intensive than on «cold»).
8. The presence of black deposits on the electrodes indicates a re-enrichment of the mixture, and if the deposits still have an oily consistency, you should also consider a more detailed assessment of the degree of wear of the internal components of the engine.
9. A coating of a golden or gray-brown hue on the insulator confirms the good condition of the engine and the correct layout of the air-fuel mixture.
10. All engines are equipped with multi-electrode spark plugs as standard. The installation of interelectrode gaps on such candles is made at the factory and does not need any adjustments.
11. When using non-standard candles with one side electrode (which is not recommended), the factor of the correct setting of the interelectrode gap comes to the fore, the value of which determines the intensity of sparking and, as a result, the correct ignition of the mixture and the development of its combustion process in all modes of engine operation. The setting of the electrode gaps must be carried out in accordance with the instructions of the spark plug manufacturers.
12. Measurement of the interelectrode gap on candles of an adjustable type is carried out using a special wire-type probe.
When adjusting, only the side electrode should be bent - attempts to deform the central electrode are fraught with irreversible damage to the insulator. A nozzle for correcting the position of the electrode is usually included with the probe.
If a conventional blade-type feeler gauge is used to measure the spark plug gap, the gap can be considered correctly adjusted when the blade (I) probes pass into it with slight resistance.
13. Before installing the candle, make sure that the threaded tip is tightly screwed on, and the threads on the body and the outer surface of the candle are well cleaned.
14. Thread one of the new spark plugs into the appropriate hole in the engine by hand. After making sure that the candle is not skewed in the thread, tighten it with the required force (with a torque wrench handy). To facilitate the process of baiting a candle, pull a piece of flexible fuel hose onto its shank. This eliminates the possibility of thread breakage, since at the slightest biting, the hose will simply begin to turn. Proceeding in a similar manner, install all the remaining candles.
15. On eligible models, before connecting BB wires to the spark plugs, follow the maintenance procedures for the spark plugs (see below).
16. The connection of the BB wire is carried out by rotational-translational movements of its tip, - the latter should sit tightly on the shank of the candle (pay attention to wire markings). On models without BB wiring, install the ignition module and tighten its fasteners to the required torque.
Checking the condition of the spark plug wires (1.6L SOHC and 2.0L models only)
Checking the condition of the explosive wiring should be done regardless of whether the spark plugs were replaced or not.
1. The check begins with an external inspection of the insulation of the wires with the engine running. Drive the car into a dark room, start the engine and make sure there is no sparking on the wires. Sparking is a sign of insulation breakdown. Avoid touching moving components in the engine compartment. Make the necessary notes on the replacement of defective wires, then let the engine cool down and proceed to check the condition of the ignition distributor cap and runner.
2. Checking the spark plug wires is carried out one by one in order to avoid violating the order of their connection during assembly. Usually, there is a corresponding marking on the insulation of branded wires. If there is none, apply it yourself with tape and a marker.
3. Disconnect the BB wire from the spark plug (it is best to use a special tool). In no case do not pull on the wire itself, only on its tip.
4. Carefully inspect the inside walls of the tip. Corrosion usually appears as a brittle, crusty, white deposit.
5. Pull the tip back over the shank of your spark plug, making sure it fits snugly. If necessary, remove the tip again and bend the terminals inside the rubber boot.
6. With a clean rag, wipe the wire along its entire length, completely removing traces of dirt and grease from the surface of the insulation. Inspect the wire insulation for cracks, burn marks, or other damage. Try not to bend the wire at sharp angles to avoid breaking the integrity of the conductor cores inside the insulation.
7. Check up a condition of contacts of wires from the ignition module, — again pull only for a tip.
8. Replacement of explosive wiring should be done as a set, even if it comes out of only one of the wires.
9. Even if the ignition system is in excellent condition, failures may occur when starting in wet weather - if necessary, spray the elements of the system with a moisture-absorbing spray - ask in car accessories stores.
Typical damage to spark plugs
Coal deposits
Symptoms: The presence of soot indicates an over-rich air-fuel mixture or a weak spark intensity. Causes misfiring, difficult starting and engine instability.
Recommendations: Check if the air cleaner is clogged, if the fuel level in the float chamber is too high, if the air damper is stuck, and if the contacts are too worn. Try using plugs with a longer insulator, which increases fouling resistance.
Oiling
Symptoms: Lubrication of the candle is caused by wear of the valve stem seals. Oil enters the combustion chamber through worn valve guides or piston rings. Causes misfiring, difficult starting and engine instability.
Recommendations: Produce mechanical restore
Overheat
Symptoms: Porous, white insulator, electrode erosion and lack of any deposits. This will shorten the life of the spark plug.
Recommendations: Check if the glow rating of the installed plugs meets the requirements of the Specifications, if the ignition timing is set correctly, if the air-fuel mixture is supplied too lean, if there are vacuum leaks in the intake pipeline and if the valves are stuck. Also check the coolant level and check if the radiator is clogged.
Too early ignition
Symptoms: The electrodes are melted. The insulator is white, but may be dirty due to misfiring or foreign particles entering the combustion chambers. May lead to engine failure.
Recommendations: Check the glow number of the installed candles, the ignition timing, the quality of the mixture (isn't it too poor), whether the cooling system is clogged and the lubrication system is functioning properly.
Electrically conductive gloss
Symptoms: The insulator has a yellowish color and a polished appearance. It speaks of a sudden increase in temperature in the combustion chambers during sharp acceleration. At the same time, ordinary deposits are melted, acquiring the appearance of a varnish coating. Causes misfiring at high speeds.
Recommendations: Change spark plugs (colder, while maintaining driving style).
Closing the electrodes
Symptoms: Waste products of combustion fall into the interelectrode space. Solid deposits accumulate, forming a jumper between the electrodes. Leads to ignition failure in the cylinder.
Recommendations: Remove deposits from the interelectrode space.
The normal state of the candle
Symptoms: Gray-brown color and slight wear of the electrodes. The number of glow plugs corresponds to the type of engine and its general condition.
Recommendations: When replacing spark plugs, use spark plugs of the same type.
Ash formation
Symptoms: Soft brownish deposits on one or both spark plug electrodes. The source of their formation is the additives used in oil and/or fuel. Excessive buildup can insulate the electrodes and cause misfiring and engine instability when accelerating.
Recommendations: If deposits build up quickly, replace the oil seals to prevent oil from entering the combustion chambers. Try changing the brand of fuel.
Wear
Symptoms: Rounding of electrodes with a slight accumulation of deposits at the working end. The color is normal. Causes engine start difficulty in cold, wet weather and increased fuel consumption.
Recommendations: Replace spark plugs with new ones of the same type.
Detonation
Symptoms: Insulators may be chipped or cracked. Insulator damage can also result from inaccurate spark plug gap adjustment. May damage pistons.
Splashing
Symptoms: After misfiring for a long period of time, deposits can loosen while maintaining the operating temperature in the combustion chamber. At high speeds, deposits flake off the piston and adhere to the hot insulator, causing misfiring.
Recommendations: Replace spark plugs or clean and reinstall old ones.
Mechanical damage
Symptoms: May be caused by foreign material entering the combustion chamber or caused by a piston hitting a spark plug that is too long. Lead to cylinder failure and piston damage.
Recommendations: Remove foreign particles from the engine and/or replace.
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