This was a job I had been putting off for a while, but given I have a four or more hour drive ahead of me tomorrow, It was time to finally replace the spark plugs.
The last change was when we got the car, 75,000km ago, by a Honda dealer (*shudder*). There are plenty of opinions on the internet about the service interval for Laser Iridium plugs, and NGK themselves say 100k MILES. The truth is that they don’t last that long without some sort of side effect.
Our Honda gets it fairly easy. The occasional Italian Tune Up to keep it breathing well, but otherwise a variety of short and long hot running. It’s always run on 95-98 octane, with occasional fuel system cleaner. It runs clean, and it runs well.
Or so it did. I have noticed over the last couple of weeks that a slight surge has found its way into acceleration. Fuel economy is still good, idling was a little rougher than usual, but the only real sign something was amiss was the surging. Most people wouldn’t notice it, but having put the majority of the 75,000km on the car myself, I couldn’t miss it. Not sure if it’s a good or bad thing being so “in tune” with the car. Good I guess.
I knew plugs were coming up, but I dreaded doing it. On the Fit the spark plugs are tucked away down the back of the engine, completely hidden and covered by both the intake manifold and the plastic cowling under the windscreen. There is no access without some disassembly.
A couple of weeks ago I purchased a set of NGK IZFR6K-13 spark plugs. These are the factory fitment plugs, and what I guessed had been fitted by Honda. They weren’t cheap, but I knew they wouldn’t need changing again for a while, and likely not in our ownership.
The four spark plugs arrived individually bubble wrapped, in individual large square boxes. Four boxes for four spark plugs. Needless to say the seller got some Neutral feedback for that one.
With the surging getting worse over the past couple of days I wanted to sort it before driving over 4 hours tomorrow (to pick up wheels for the M328i). I had some time after work today so got stuck in.
Step one is to remove the windscreen wipers. Remember to mark their position on the screen for refitting, with tape, or make sure there are obvious “wipe” marks where they rest. Remove the black caps over the securing nuts, they just pull off by hand, and then remove the nuts. The Wipers are a press fit on the splines, and can be easily released by lifting the arm away from the screen and rocking the arm.
Each one is held down with a 10mm bolt, on the passenger’s side of the coil. The connector has a latch on the top to press to release it. I removed the coils one by one so I didn’t mix them up, and removed the plugs. A magnet stick can help to remove the old plug from the head once unscrewed.
The plugs didn’t actually look too bad. Not oily, not black, not wet. Old, but the colour is good, which indicates a good mixture. The gap was noticeably wider than the new replacements though, so they had clearly worn over that time.
I fit the new plugs, with the recommended “torque setting” of hand tight and then 1/2-2/3 turn. A quick check of each coil before fitting, for cracks or other damage, and back in they went.
Unfortunately I was annoyed to find that plug number four was only barely tighter than finger tight on removal, and my rocker cover gasket is weeping. I won’t be getting Honda to do anymore work on the car, I’m sick of fixing their mistakes.
Speaking of Honda breaking things, I mentioned the cowling has a series of clips under the windscreen. Well, I purchased some spares a while back on the recommendation of a post on a forum, as they can break. They can be purchased from eBay under PN 90602-TAO-003.
The results so far seem to be good. A quick drive shows no signs of surging, a small increase in power/punch, and an idle so smooth it’s like the engine isn’t even running.
All in all, seems like a success so far, and worth doing. I’d say give plugs 60,000km MAX, before changing. That’s still a lot of miles, but less than recommended and gives enough time between changes that you don’t dread having to rip it all to bits too often. In saying that, this job was actually easier than I expected, and I would recommend it to anyone with a basic tool kit, and the desire to give it a go. Damn sight better than paying someone else to break your stuff.