3.21. Check and replacement of spark plugs and module of ignition

Spark plugs should be replaced only on cold or slightly warm engine. The reversing of candles on the hot engine can entail damage of a carving to a head of cylinders.

Socket and bolts of fastening of the module of ignition of the 4-cylinder engine

Socket and bolts of fastening of the forward module of ignition of the V6 engine

Socket and bolts of fastening of the back module of ignition of the V6 engine


  1. Switch off ignition.
  2. On models with V6 engines remove a decorative cover of the engine.
  3. Carefully separate the socket(s) of an electrical wiring of the module(s) of ignition and turn out bolts of fastening of the module(s).

At removal of the back module of the V6 engine previously it is necessary to separate the MAP sensor electrical wiring socket (see the illustration Arrangement of Components of a Control System of the V6 Engine).

  1. Remove the ignition module together with rubber consolidations from spark plugs and turn out spark plugs a candle key, trying not to incline it.
  2. Estimate a condition of spark plugs, check their interelectrode gap. If necessary correct possible malfunctions about which it is possible to judge by a condition of candles (see the table below).
  3. Grease a carving of candles with means of Molycote 1000 or similar. Grease rubber consolidations with Krytox lubricant.
  4. Establish new spark plugs and tighten them with the required effort.
  5. Install the ignition module with rubber consolidations, tighten bolts of its fastening and join the electrical wiring socket(s), previously having cleared contacts (for example, Kontakt 61 spray).
  6. On the V6 engine after installation of the back module of ignition join the MAP sensor electrical wiring socket. Establish an engine cover.

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.


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.


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.

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.

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).

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.

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.


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.


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.


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.


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.

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 candles.