Checking the condition and replacing spark plugs (Honda Accord 6)

(every 48,000 km [30,000 miles] or every 24 months)



If the original spark plugs are to be reinstalled on the engine after checking their condition, they must be screwed strictly into the previous cylinders - mark them accordingly.

1. When checking/replacing spark plugs, do not forget to also evaluate the condition of the high-voltage wires connected to them.



2. In most cases, replacing spark plugs requires a special spark plug head (with an elastic insert inside) complete with a ratchet drive, as well as a set of wrench drive extensions and a tool for checking and adjusting interelectrode gaps. A special tool is also available for safely disconnecting the high-voltage wire tips from the spark plug tails, although its use is not strictly required. Using a torque wrench will allow you to achieve the correct tightening force for the spark plugs.

3. It is best to keep a set of replacement spark plugs with the correct gap adjustment in your vehicle at all times. When purchasing new spark plugs, make sure that they meet the parameters of your vehicle's engine. The necessary information is provided in the Specifications to this Chapter and on the VECI label attached under the hood (in case of discrepancies, the VECI information should prevail).

4. Start removing the spark plugs only after the engine has completely cooled down. In order not to waste time, use the pause to check the condition of the replacement spark plug set.





5. The spark plug gap is checked by inserting the appropriate feeler gauge into it and must meet the requirements specified on the VECI label. The feeler gauge must slide between the side and central electrodes of the spark plug with slight resistance. The gap can be adjusted using a special device, usually included in the measuring device - bend the side electrode of the spark plug accordingly. If the side electrode is not located exactly above the central one, adjust its position accordingly. Make sure that there are no cracks or other damage in the porcelain insulator of the spark plug. The presence of any kind of defects in the insulator is unacceptable.



6. With the engine cold, disconnect the high-voltage wire from the spark plug of the first cylinder (see Section Checking the condition and replacing the spark plug wires, cover and distributor rotor). Pull only the tip, and never the wire! It would be wise to use a special tool.

7. If you have a source of compressed air at hand, use it to remove debris from the spark plug niches of the engine (a regular bicycle pump will work just as well for this purpose).

Warning! When using compressed air, remember to wear safety glasses!

8. The spark plugs on some of the models under consideration are deeply recessed into the spark plug recesses, so you will need a wrench drive extension to unscrew them. After placing the head on the spark plug, connect the drive and, carefully turning the wrench counterclockwise, unscrew the spark plug (see the accompanying illustration).



9. Compare the removed spark plug with the condition chart shown in the photographic insert, which will allow you to qualitatively assess the overall condition of the engine. Before screwing in new spark plugs, lightly lubricate their threaded part with anti-seize sealant (see accompanying illustration).





10. Manually thread one of the new spark plugs into the appropriate hole in the engine. After making sure that the spark plug is not twisted in the thread, tighten it to the required force (if you have a torque wrench at hand). To make the process of threading the spark plug easier, pull a piece of flexible fuel hose over its tail (see accompanying illustration). This eliminates the possibility of stripping the thread, since the slightest biting will simply cause the hose to turn.

11. Before connecting the high-voltage wires to the spark plugs, follow the procedures in Section Checking the condition and replacing the spark plug wires, cover and distributor rotor.

12. The high-voltage wire is connected by rotating and reciprocating movements of its tip - the latter should fit tightly onto the spark plug tail.

13. Repeat the procedure for the remaining spark plugs, performing all steps in turn to avoid disrupting the order of connecting the high-voltage wires.

Coal deposits

Symptoms: The presence of soot indicates an over-enriched fuel-air mixture or weak spark intensity. Causes misfires, makes starting difficult and leads to unstable engine operation.



Recommendations: Check if the air cleaner is clogged, the fuel level in the float chamber is too high, the choke is stuck and the contacts are too worn. Try using spark plugs with a longer insulator, which increases resistance to contamination.

Normal condition of the candle

Symptoms: Gray-brown color and slight wear of the electrodes. The glow number of the spark plugs corresponds to the type of engine and its general condition.

Recommendations: When replacing spark plugs, install spark plugs of the same type.

Oiling

Symptoms: Oiling of the spark plug is caused by wear of the oil-deflecting caps. Oil gets into the combustion chamber through worn valve guides or piston rings. It causes misfires, makes starting difficult and leads to instability of engine operation.



Recommendations: Perform mechanical repairs and replace spark plugs.

Ash formation

Symptoms: Soft, brownish deposits on one or both spark plug electrodes. They are caused by oil and/or fuel additives. Excessive buildup can insulate the electrodes and cause misfires and rough running under acceleration.

Recommendations: If deposits accumulate quickly, replace the oil seals to prevent oil from entering the combustion chambers. Try changing the fuel brand.

Overheat

Symptoms: Porous, white insulator, erosion of electrodes and absence of any deposits. Leads to a reduction in spark plug life.

Recommendations: Check that the spark plug heat range is correct, that the ignition timing is set correctly, that the fuel/air mixture is not too lean, that there are no vacuum leaks in the intake manifold, and that the valves are not stuck. Also check the coolant level and that the radiator is not clogged.

Wear

Symptoms: Rounding of the electrodes with a small accumulation of deposits at the working end. The color is normal. It leads to difficulty in starting the engine in cold, wet weather and increased fuel consumption.

Recommendations: Replace the spark plugs with new ones of the same type.

Too early ignition

Symptoms: The electrodes are melted. The insulator is white, but may also be contaminated due to misfires or foreign particles entering the combustion chambers. May cause engine failure.

Recommendations: Check the glow plug rating, ignition timing, mixture quality (is it too lean), is the cooling system clogged, and is the lubrication system functioning properly.

Detonation

Symptoms: Insulators may be chipped or cracked. Inaccurate spark plug gap adjustment techniques may also damage the insulator. Piston damage may result.

Conductive gloss

Symptoms: The insulator has a yellowish color and a polished appearance. Indicates a sudden increase in temperature in the combustion chambers during sharp acceleration. Normal deposits melt, acquiring the appearance of a varnish coating. Leads to misfires at high speeds.

Recommendations: Change the spark plugs (colder ones, while maintaining the same driving style).

Splashing

Symptoms: After a long period of misfire, deposits may become loose while the combustion chamber remains at operating temperature. At high speeds, deposits flake off the piston and stick to the hot insulator, causing misfires.

Recommendations: Replace the spark plugs or clean and reinstall the old ones.

Short circuit of electrodes

Symptoms: Combustion waste gets into the interelectrode space. Solid deposits accumulate, forming a bridge between the electrodes. Leads to ignition failure in the cylinder.

Recommendations: Remove deposits from the interelectrode space.

Mechanical damage

Symptoms: Can be caused by foreign materials entering the combustion chamber or occur when the piston hits a spark plug that is too long. Leads to cylinder failure and piston damage.

Recommendations: Remove foreign particles from engine and/or replace.