Nissan Maxima QX

1. In most cases replacement of spark plugs requires existence of a special candle head (with an elastic insert inside) complete with the ratchet drive, and also a set of extenders of the drive of a key and the device for check and correction of interelectrode gaps. For a safe detachment of tips of VV of wires from shafts of spark plugs the special tool is also issued though its application and is not strictly obligatory. Use of a dynamometer key will allow to achieve the correct effort of tightening of candles.
2. It is the most correct to keep constantly in the car a set of replaceable spark plugs with the correct image the adjusted interelectrode gap. Upon purchase of new candles you watch that they met for the parameters the requirements of the engine of your car. Necessary information is provided in Specifications to the present Chapter, and also on VECI label fixed under a cowl (in case of discrepancies preference should be given to information with VECI).
3. Start a reversing of candles only after full cooling of the engine. Not to waste in vain time, use a pause for check of a condition of a replaceable set.
4. The interelectrode gap of a candle is checked by introduction to it of the corresponding probe of the measuring instrument and has to conform to the requirements given on VECI label (see also Specifications). The probe has to with an easy resistance slip between side and central electrodes of a candle. Correction of a gap can be made by means of the special adaptation which is usually a part of the measuring instrument - turn in appropriately side electrode of a candle.

5. If the side electrode is located not precisely over central, correct its situation as appropriate. Make sure of lack of cracks and other damages to the porcelain insulator of a candle. Existence of any sort of defects of the insulator is inadmissible.

6. On models 1993 and 1994 of of the issue in order to avoid confusion at assembly before a detachment mark VV candle wires. Disconnect VV a wire from a spark plug of the first cylinder. Pull only for a tip, and not for a wire at all! It will be reasonable to use the special tool.

7. In the presence of near at hand source of compressed air, use it for removal of garbage from candle niches of the engine (the ordinary bicycle pump will be suitable for this purpose also not worse).

When using compressed air do not forget to put on goggles!

8. Turn out spark plugs. In order to avoid confusion with connection of wires/coils, you make replacement of each of candles serially.

9. Verify the turned-out candle with the ID card given below that will allow to estimate the general condition of the engine qualitatively.

Coal deposits

Symptoms: Availability of soot indicates reenrichment of fuel-air mix or weak intensity of a spark. Causes admissions of ignition, complicates start and results in instability of operation of the engine. Recommendations: Whether check the air cleaner is hammered whether fuel level in the float-operated camera is not too high, whether the air gate is jammed and whether contacts are not too worn-out. Try to use candles with longer insulator that increases the resilience to pollution.

Normal state of a candle

Symptoms: Gray-brown color and easy wear of electrodes. The Kalilny number of candles corresponds to type of the engine and its general state. Recommendations: When replacing candles establish candles of the same type.

Oiling

Symptoms: Oiling of a candle is caused by wear of maslootrazhatelny caps. Oil gets to the combustion chamber through worn-out guides of valves or piston rings. Causes admissions of ignition, complicates start and results in instability of operation of the engine. Recommendations: Perform mechanical recovery work and replace candles.

Peploobrazovaniye

Symptoms: Soft deposits of brownish color on one or both electrodes of a candle. A source of their education are the applied additives to oil and/or fuel. Excessive accumulation can lead to isolation of electrodes and cause admissions of ignition and unstable operation of the engine at acceleration. Recommendations: At bystry accumulation of deposits change maslootrazhatelny caps that will prevent hit of oil in combustion chambers. Try to replace fuel brand.

Overheat

Symptoms: Porous, white insulator, erosion of electrodes and lack of any deposits. Leads to reduction of service life of a candle. Recommendations: Check whether the kalilny number of the established candles conforms to requirements of Specifications, whether the ignition advancing corner is correctly exposed, whether too poor fuel-air mix moves, whether there is no leak of vacuum of the inlet pipeline and whether valves are jammed. Check also the level of a cooler and whether the radiator is corked.

Wear

Symptoms: A rounding off of electrodes with a small congestion of deposits on the working end. Color is normal. Leads to difficulty of start of the engine in cold damp weather and to increase in fuel consumption. Recommendations: Change candles on new, the same type.

Too early ignition

Symptoms: Electrodes are melted off. The insulator has white color, but maybe is polluted owing to admissions of ignition or hit in combustion chambers of foreign particles. Can lead to an engine exit out of operation. Recommendations: Check kalilny number of the established candles, an ignition advancing corner, quality of mix (whether it is not too grown poor) whether the cooling system is corked and whether the lubrication system normally functions.

Detonation

Symptoms: Insulators can be chopped off or burst. Also inaccurate technology of adjustment of a candle gap can lead to damage of the insulator. Can lead to damage of pistons.

Electroconductive luster

Symptoms: The insulator has yellowish color and the polished appearance. Speaks about sudden temperature increase in combustion chambers at sharp acceleration. Usual deposits at the same time are melted off, taking a form of a varnish covering. Leads to admissions of ignition at high speeds of the movement. Recommendations: Replace candles (colder, at preservation of a manner of driving).

Zabryzgivaniye

Symptoms: After admissions of ignition during a long period of adjournment can be loosened at preservation of working temperature in the combustion chamber. At high speeds of adjournment in flakes come off the piston and stick to the hot isolation center, causing admissions of ignition. Recommendations: Replace candles or smooth out and establish into place old.

Short circuit of electrodes

Symptoms: Waste of products of combustion gets to interelectrode space. Firm deposits accumulate, forming a crossing point between electrodes. Leads to refusal of ignition in the cylinder. Recommendations: Remove deposits from interelectrode space.

Mechanical damages

Symptoms: Can be caused by hit of foreign materials in the combustion chamber or arise at blow of the piston about too long candle. Lead to refusal of functioning of the cylinder and to damage of the piston. Recommendations: Remove foreign particles from the engine and/or replace

10. Before rolling new candles, slightly grease their carving part with the anti-taking sealant. Manually acquire one of new candles in the corresponding opening in the engine. Having made sure that the candle is not warped in a carving, tighten it with the required effort (in the presence of near at hand dynamometer key). For simplification of the procedure of a nazhivleniye of a candle pull a piece of a flexible fuel hose on its shaft. At the same time the probability of failure of a carving as at the slightest zakusyvaniye the hose will begin to be turned simply is excluded.

11. On models 1993 and 1994 of of the issue connection of VV of a wire to a candle is carried out by rotary progress of its tip, - the last has to sit down on a candle shaft densely. The individual candle coils used on release models since 1995 are equipped with own short candle wires, - at installation just densely put assembly on the candle, without rotating it on a shaft of the last.
12. Repeat the procedure for the remained spark plugs, performing all operations serially in order to avoid violation of an order of ignition.