Spark plug analysis

How do you Analyse a spark plug?

  1. The first step is removing the spark plug you want to look at. …
  2. A normal spark plug will have brown or grayish-tan deposits on the side electrode. …
  3. Black, dry soot on the electrodes and insulator tip indicates a carbon-fouled plug. …
  4. Black, oily deposits on the electrodes and insulator tip points to an oil-fouled plug.
  5. What is a good ohm reading for a spark plug?

    When spark plugs are new, the resistance value is between 500 and 3000 ohms. As the plug ages, values below 5000 ohms are acceptable. But once the plug’s resistance value exceeds 5000 ohms, the plug should be replaced.

    What do the spark plug numbers mean?

    The heat range of a spark plug is the range in which the plug works well thermally. The heat rating of each NGK spark plug is indicated by a number; lower numbers indicate a hotter type, higher numbers indicate a colder type.

    What Colour should a healthy spark plug be?

    Normal Spark Plug Color

    Combustion deposits are slight and not heavy enough; to cause any detrimental effect on engine performance. Note: The brown to greyish tan color and minimal amount of electrode erosion. Furthermore, indicating the plug is in the correct heat range; and, has been operating in a “healthy” engine.

    How do you read a lean or rich spark plug?
    Part is the porcelain now what you're looking at the porcelain for at all times as you're looking for a rich lean condition. Now this is gasoline or 85. This was in particular a gasoline spark plug.

    What do black spark plugs mean?

    Black spark plugs are a sign of a weak spark or too much fuel in the air-fuel mixture.

    How can you tell when a spark plug is bad?

    What signs are there that your spark plugs are failing?

    1. Your car is a rough starter. …
    2. Your car is a rough idler. …
    3. Your engine will sometimes misfire. …
    4. Your engine surges. …
    5. Your fuel consumption is higher than usual. …
    6. Your car isn’t accelerating as it should.

    How many ohms should a non resistor spark plug have?

    To help assure reliable and trouble free operations, Tempest recommends replacing spark plugs in service having a resistance value of more than 5000 ohms (5k ohms) or less than 500 (0.5k ohms). For new plugs, we recommend 4000 ohms as the maximum acceptable value.

    Should a spark plug have continuity?
    And there should be continuty. But it just means that you have excessive carbon buildup on this and you need to clean this as well.

    What causes orange spark plugs?

    Orange spark is a weak spark. It very well could be a weak ignition coil.

    What does white spark plug mean?

    run too hot

    If your spark plug is white in color or appears blistered, that means something is making the plug run too hot. Check for problems in your engine’s cooling, a lean fuel mixture or incorrect ignition timing.

    What does a grey spark plug mean?

    In general, a light tan/gray color tells you that the spark plug is operating at optimum temperature and that the engine is in good condition.

    What does a red colored spark plug mean?

    However, don’t be dismayed if ceramic insulator tips (center and ground electrodes on a plug) are pinkish-red in color. That pink coloration is created by deposits from additives in unleaded fuel when they’re burned off during combustion.

    How long are spark plugs good for?

    A standard copper spark plug has an average life span of 10,000-20,000 miles. Silver plugs, used for older vehicles, can last up to 20,000 miles. Expensive iridium spark plugs or platinum spark plugs can last 60,000 miles. Extended life spark plugs or long life spark plugs can last 100,000 miles.

    What color should spark be on spark plug?


    The strength of the spark is revealed in the color. A red or yellow spark is weak and probably will not spark in the cylinder. A blue or white spark is strong and has enough voltage to fight across the spark plug gap even under pressure within the cylinder.

    What does weak spark look like?

    A good spark will be blue-white and will be plainly visible in daylight. If a good spark is present, the problem is probably not in the ignition system. Check the fuel system and/or stark timing. Weak sparks are orange or red and may be hard to see in daylight.

    What causes weak spark?

    A weak spark, or no-spark, problem may originate within one or more common ignition system components: Worn or damaged spark plug wire insulation. At high temperature, this problem can produce bucking or misfires. Dirty or worn spark plug.