I changed the spark plugs on my 2013 Fit Sport MT with about 70K miles on it. It wasn't having issues prio, changed them mainly as good practice /preventative maintenance. However after installing my new NGK laser iridium spark plugs, the car seems to run poorly. It started ok after installation but not the next day when I was going to take it to Home Depot - it wouldn't start. I just tried again earlier today and it started but didn't sound like it was having a good time getting there, so I have not driven the car yet in case harmful. Thinking about buying a diagnostic car code reader to help figure out the issue. Im new to DIY car repairs but have been reading this forum for a few weeks, so I thought I'd see if you guys have any insight on this issue.

Other info to disclose - I torqued the plugs using an old school style torque wrench that has a bar-style measurement gauge, not perfectly accurate, but I torqued the plugs to between 17-19 lbs. I used dialectric grease on the ceramic portion of plugs and inside the coils using q-tips. I did not use anti seize on the threads.

 

Well, for one thing, the Fit is rated for 100k miles before changing the spark plug. I went 134k miles on my factory plugs. You did something quite unnecessary, and in fact, potentially headache inducing... cause there's multiple threads about how people are having trouble with the plugs coming loose after the first change (myself included).

Did you check the plugs to make sure they weren't loose?

 

Do you have a CEL (Check Engine Light) illuminated? If not, a code reader might not be of help. If you do see a CEL, perhaps a coil pack might have gone bad? A reader will tell you which one.

Did you gap the plugs before installing them? This step seems to be increasingly unnecessary in this era and can damage the electrodes if not done carefully.

Your old skool beam-type torque wrench is fine. These are durable and accurate tools.

Good luck with your solution.

 

Maybe a few cylinders are not getting proper spark.

What do you mean by the car won't start? Does the starter motor sound the same as always? Does the starter motor sound weak or slow? Will the he engine will not run on its own?

How did engine start and run right after the change? Did both sound perfect?

Did you disconnect the battery or anything else when doing the spark plug work? Disconnect those wires check contacts and reconnect.

When installing each coil pack, I think you need to hear a click (indicating the coilpack has engaged with the metal top of the spark plug). For sure there was that very difficult plastic tab to remove the coil packs but just can't remember on the Fit.

After the install, each coil pack has a screw which you also need to tighten down (I think torque spec was about 7ft/lbs but look that up).

Is it possible that you dislodged a wire (for example the other end of the wires of the coil pack?

Did you measure the gap of the spark plugs? You can't touch the delicate Iridium tips with anything or gap them but you should try to eyeball gap with gauge nearby.

Did you confirm that the plug model numbers ordered were same as model numbers received?

 

Hah! I was thinking the same exact thing: did they click into the packs?

Based on the procedure.. theres no essential components involved besides the plugs/coils. There was some kind of clippy there, I'm fairly confident. I'd also join the club and recommend taking stuff off down to the plugs, leaving the plugs themselves in, but checkin out the coils.

Since you mentioned pasting up in the coils with a Q-tip I've gotta wonder.. did you disconnect the battery for this procedure? And if so, did you tighten it's clamp back onto the battery terminal nice and snug?
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Reverse what you did. Reinstall the old plugs and see if it fixes the problem. You said it was running fine before that.

If it returns to normal (good running order) then it must be the spark plugs. If not running well, look further. If you aren't getting a check-engine-light CEL), you probably don't have codes to read, so a scan tool would be a waste of money.

Go backwards to go forwards.

 

Check all electrical connectors. I'm betting you have an unplugged coil pack or something around the throttle body.

Bravo to you for doing pre-preemptive maintenance! At 6 years old, it's not too early. Just have to figure out what went wrong.

 

Please let us know what fixed it when you do..........

z

 

Just to update you guys on this issue, I was out of town for a couple days, just got back. I drove the car to the grocery store and back - it seemed fine; started normally and idled smoothly. My dad wondered if it could have been water related, I (foolishly) installed the new spark plugs a day after it had rained considerably. There might have been water or moisture interfering. I'll keep you guys posted if the issue comes back.

 

Yeah I hear that, it might not have been the greatest idea. The car is comprised of I would say 75% city miles, so I thought that might have been harder use than a normal car with the same mileage.
I have not checked the plugs to see if they're loose. Maybe I should do that. Its just such a pain taking the pieces off to get access lol

 

Thank you. I don't have a check engine light and never did. I did not gap the plugs. Ok good to know that someone else has a positive opinion of old skool beam-type torque wrenches!

 

The starter sounded normal. When I started it up after install it seemed normal but I wasn't super attentive (i assumed it would be totally fine). I just updated the thread with a post suggesting the issue could have been water/moisture related as I installed day after large rain downfall. The car seems ok now.
I didn't measure the gap of the spark plugs. I briefly eyeballed and they looked to spec. I confirmed that the NGK spark plugs were the correct ones but I haven't been able to determine if they are 'fakes' - I see NGK has a document to help determine this but I found it somewhat unclear.

 

I did not disconnect the battery for any part of the install. Maybe I should have. The car seems ok now but I will definitely take it all apart if the problem comes back

 

Thank you, I will hold off on the scan tool purchase. You saved me money! lol. I will reverse what I did if I have to. The car has been running ok since I had that issue. Will update if problem comes back

 

Thank you sir

 

I forgot about the spark plug fakes.

Avoid Amazon and eBay for critical items as the supply chain is a black hole. Knock-offs are getting increasingly difficult to identify but you pay the price with bad performance or premature failure.

I feel more comfortable buying OEM & top-brand parts from shops with legitimate supply chains: Honda dealers, well-established local stores, and maybe RockAuto.

 

You make a good point. I bought the plugs on Amazon and the supplier was new so there weren't even reviews - to save a few bucks, sketchy in hind sight. I think I'll avoid that in the future

 

I was about to hit buy on some ik22 plugs from a Amazon seller with many reviews, but now you have got me rethinking ...

 

RockAuto is usually close in price. Worth checking at least.

 

I recently bought a set of Denso spark plugs from Rock Auto, and they were genuine of course. They have become my go-to for parts, as they usually have a selection in stock, and searching/ordering is so simple.