What fouls do I look for on a spark plug - Cars & Trucks

We are unacquainted with your car in the states, from which you are receiving this answer.
If you vehicle is carbureted, you should be needing a carburetor overhaul, or at least some serious adjustment of the fuel mixture.
If that is not the problem, next might be the valve stem seals, which, if worn out or damages, will cause excess oil to be drawn into the combustion chamber, fouling your plugs.
This fix is to install new valve stem seals.
Lastly, back in the days before American cars had fuel injection, a person could read the plug by it's number, and if fouling was a problem, one could buy a "hotter" plug which would help burn that oil or gas which was fouling the plugs.
God bless your efforts.

Fouled spark plugs are when they aren't firing, causing a cylinder misfire. Can be caused by a burnt electrode inside the plug from being old OR too much carbon or oil on the tip between the electrodes where the plug fires.

Well it depends on the color of smoke if it's WHITE; it could be a blown head gasket (check coolant levels and then oil to see if it is milky looking) BLUE: could be burning oil, which could result to fouling plugs (check spark plugs for fouling) BLACK; too much fuel flooded (check spark plugs for fouling)

spark plugs ruined/fouled, spark plug wires ruined/fouled, if the cylinders have individual coil packs then ruined/ fouled. if there is gas that means that spark isnt happening. something to do with that situation.

Hi Dale,

Several factors can contribute to spark plug fouling:

- The air/fuel ratio may be too rich as a result of incorrect carburetor adjustment or a poorly performing fuel injection system.
- Worn piston rings or valve seals may allow too much oil to leak into the combustion chamber, leading to oil fouling.
- The ignition system may not be performing properly.
- Prolonged idling or continuous low-speed driving may keep the spark plug from reaching its optimum operating temperature. Using too cold a spark plug can lead to the same problem.
- A dirty air cleaner can create a too-rich condition which can lead to fouling.

Have each of the above checked and corrected.

Fuel, oil and carbon fouling can all be the result of different causes but, once a spark plug is fouled, it will not provide adequate voltage to the firing tip and that cylinder will not fire properly.

In many cases, the spark plug cannot be cleaned sufficiently to restore normal operation. Hence, I always recommend that a plug be replace, once it becomes fouled.

Cheers,

Scott


"If this has helped you in any way, please be kind enough to rate this solution"

Hi Dale,

Several factors can contribute to spark plug fouling:

- The air/fuel ratio may be too rich as a result of incorrect carburetor adjustment or a poorly performing fuel injection system.
- Worn piston rings or valve seals may allow too much oil to leak into the combustion chamber, leading to oil fouling.
- The ignition system may not be performing properly.
- Prolonged idling or continuous low-speed driving may keep the spark plug from reaching its optimum operating temperature. Using too cold a spark plug can lead to the same problem.
- A dirty air cleaner can create a too-rich condition which can lead to fouling.

Have each of the above checked and corrected.

Fuel, oil and carbon fouling can all be the result of different causes but, once a spark plug is fouled, it will not provide adequate voltage to the firing tip and that cylinder will not fire properly.

In many cases, the spark plug cannot be cleaned sufficiently to restore normal operation. Hence, I always recommend that a plug be replace, once it becomes fouled.

Cheers,

Scott


"If this has helped you in any way, please be kind enough to rate this solution"

It can be cleaned and you must use a sand blaster (by far the best way to clean them) that is just for spark plugs. Another method is to use a wire brush and carburetor spray cleaned. Below is a link to the spark plug sand blaster i mentioned.


http://www.sears.com/shc/s/p_10153_12605_SPM211697464P?sid=IDx20101019x00001a&ci_src=14110944&ci_sku=SPM211697464

Is it oil fouled? If so, replace spark plug wire. If it's coolant fouled you have a blown head gasket.

If you are telling the compression it fine i advice you to to put new spark plugs then see what it gives,then you will know what step to take after ,hope that help you and solve it.

Fouling occurs when the spark plugs' firing tip becomes coated with excessive fuel, oil, or combustion deposits so that it is unable to produce a spark. A plug can become fouled from continuous low speed driving, improper spark plug heat range (too cold), improper timing (over-retarded), too rich an air/fuel ratio or an oil leak into the combustion chamber. A variety of self-cleaning features are designed into most plugs to reduce fouling.