When starting a vehicle, we don’t typically stop to think about all of the components and processes that make this action possible.
Spark plugs and ignition coils are some of the little guys that are working behind the scene.
So, what do spark plugs do? Spark plugs team up with ignition coils and other components to get your vehicle to start. Fuel that is located in the cylinder head is sparked by the spark plugs. Ignition coils lend a hand by producing the voltage.
When to change spark plugs
How often to replace spark plugs has changed. These components have a much longer lifespan today. They used to be replaced around the 30,000 mile mark. This has been extended to between 60,000 and 105,000 miles.
However, you should consult your manual for the manufacturer guidelines for your vehicle or feel free to contact your local auto repair shop.
If you’re wondering how to tell if a spark plug is bad, here are some indicators:
- The check engine light turns on
- You’re having trouble starting your vehicle
- Your car runs rough when idle
- Engine misfires (You may feel that your car is chugging when going up a hill or accelerating.)
With today’s vehicles, with OBDII systems if you feel the vehicle not running correctly and the check engine light is flashing you definitely have a misfire that could be causing catalytic converter damage.
Because of all the computer systems and safety systems in cars and trucks, if you have an engine running problem it could impact other safety systems, such as traction control and Advanced driver-assistance systems (ADAS) systems. Since the engine wouldn’t be running correctly, the computer may turn those systems off when you have a problem.
If you are having a misfire, you need to get it diagnosed by your local auto mechanic to actually get to the bottom of the problem. Starting with computer diagnostics and pulling the code that may just show a cylinder misfire doesn’t really help you pinpoint the issue. They may need to perform some testing to determine if it’s a spark plug, coil boot, ignition coil, or an ignition control problem, such as an ECM (car’s computer) or an ignition module.
Types of spark plugs
There are different kinds of spark plugs produced. When replacing them on your vehicle, it’s important that you use the right type and avoid choosing the cheapest option.
We recommend using O.E. manufacturer specific spark plugs over O.E. equivalent, and here’s why:
Certain spark plug manufacturers are associated with specific vehicle manufacturers. For example, Bosch is known for producing parts for European vehicles. Many of these manufacturers will also make spark plugs for other vehicles, and they may work just fine. However, they also might not for the long haul. This can be for various reasons, like the tolerances being off.
In addition to having spark plugs produced by various manufacturers, you now have different metals being used. There are tips made out of platinum and iridium. This can impact how long a spark plug lasts.
What can cause spark plug problems
There are quite a few issues that can cause a bad spark plug.
Spark plugs could go bad if carbon builds up, which may be a result of dirty air filters or fuel injectors, or if the fuel-air combination is too rich.
The spark plug tip becoming overheated multiple times, and engine oil entering the combustion chamber are other culprits of spark plug failure.
Overtime, the gap will get bigger, due to the metal wearing away from everyday use.
A lot of engines are designed where the spark plug is located in a tube in the middle of the cylinder head. The gaskets and seals can leak into the spark plug tubes. So, in some instances the fix may be replacing the spark plugs and the spark plug boots and also the valve cover gasket and spark plug tube seals.
How to tell if ignition coils are bad
If you notice that your car is misfiring or stalling, it could be an indicator of a bad ignition coil. Other symptoms include rough idle, misfire during acceleration, and hard start.
This part may stop working correctly if a vehicle has bad spark plugs or plug wires, or if there is an overload with the voltage.
Like spark plugs, ignition coils can be designed differently. Sometimes, ignition boots come separate from ignition coils.
There are four types of ignition coils: conventional, electronic, coil packs, and coil-on-plug. Without getting too much into the weeds, each type of coil has the same purpose of producing high voltage to the spark plug but are designed differently.
Steve’s Auto Repair & Tire is an authorized Goodyear tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including BMW and Mercedes. Services include oil changes, brakes, alignments, inspections, and computer engine diagnostics.