Do you need to replace your ignition coils when you replace spark plugs? – Jalopnik

You sit hunched over the bike with your wrist painfully twisted, wishing you were Mr. Fantastic. You finally removed the broken spark plug number four and then comes the intrusive thought. “Do I also need to replace the ignition coils?” The urge is tempting; Since you are in that situation, you can kill two birds with one stone. But should you?

To understand the argument, you need to know how these parts work together. The spark plug naturally provides the spark. But the ignition coil is the little transformer that steps up your battery’s mild 12 volts to something aggressive enough to ignite a combustion mixture. They are teammates, and when one slackens, the other suffers.

Many mechanics claim that coils should not be replaced unless they are actually breaking. Ignition coils don’t wear out the same way spark plugs do, so pay attention to their own warning signs. The symptoms are usually obvious: misfires, rough idling, sluggish acceleration, or fuel economy so poor that your wallet starts complaining.

Some shops recommend replacing both at the same time because their lifespans tend to overlap. Coils usually fail around the 100,000 mile range. Of all the different types of spark plugs, iridium spark plugs have the closest comparable lifespan. If you use weaker spark plugs that need replacing, the extra stress they put on your car can also shorten the life of the coil. Weak plugs can cause a coil to become overloaded and eventually break.

Ignition coils and spark plugs must be replaced regularly. Not as frequent as the ridiculous 3,000 mile oil change rule, but many owners forget about this practice.

Sometimes you get frustrated trying to guess which part is broken and think, “Why don’t we change everything?” The coils work as a group, so it is ideal to replace them all at once. If one coil is rotten, others may be as well. Changing one piece at a time is fine if you’re on a budget or if you’re experienced enough to identify what the problem is. Some owners think it’s just an added expense and impractical to throw away non-defective coils. But it’s really up to you.

Another reason to replace everything at once is accessibility. Some engines bury ignition coils under intake manifolds or plastic climbing frames, with those poor designs making your job much more challenging. If you are not that flexible, it may make sense to join coils and plugs together. Take your ride to your trusted repair shop if you don’t have the diagnostic tools or testers; they will know how to deal with it. Just have that debit card, credit card or Cash App ready, because you’re going to spend a lot. And whatever you do, skip the nameless bargains that might not even last a few weeks. Don’t give yourself another problem.