The plugs have explosive force pressing against them. On engines with good piston rings and fairly high compression (10.4:1 for the L15A7) plugs can eject out with enough force, as others here have experienced, to crack the cylinder head.
​​​​​​With a 93 jeep cherokee I worked on for a friend (long gaps between) I left plugs barely threaded to keep dirt out, maybe 0.5-1.5 turns. Came back a month later, cranked it, and the plugs just rattled in place while I moved it across the driveway.
On a 91 chevrolet with a gm 3.1L I had a plug take a huge chunk out of the cylinder head when it ejected. Not sure what it was I did wrong that time.

I would think the big thing is their breaking loose in the first place. With the fit, I've found mine barely hand-tight at times but never had an ejection. I played around with different methods of securing the plugs, reusing old ones, ect. and whenever I noticed it getting jittery leaving a full stop I'd check. No idea on the time-frame between loose and ejected, but yeah, I'd expect it to be relatively short.

 

Run a mix of sea foam and engine oil and change oil frequently.

You can run sea foam and engine oil should clean that over time with frequent changes.

 

Hi Odie, Your reference above to the Honda 'Tech Line Summary Article' seems to explain a lot! Looks like it is part of an American Honda online service manual.

I'm looking for something similar from Honda Australia but I imagine it is probably buried in their system and not sure they will want to share it.

Does anyone know of an equivalent item from Honda Australia ?

 

Hello, I never changed my spark plugs or ignition coils on my 2009 fit sport trim. I never touched the plugs.
I bought new plugs and would like to know what is torque recommended and if I do need to use anti seize? Don't feel like I need to change my ignition coils. Hope I can make that car reach 400,000 miles. Passenger side wheel bearing once. I only have changed the serpentine belt once and the shocks once. Changed the AC unit at 185kmiles. Original water pump and clutch (manual). I use amsoil with one oil change a year or 25kmiles.

 

DavidL , you may want to consider calling local HONDA service center(s) and ask about the loose spark plugs to see if they will cover the cost fully or partial . Best of luck .

 

Please. This needs to be recalled. Had the same thing happen to us. I'm good with law tho so legally forced the dealership into submission and they replaced the whole motor at like 60k miles. Well, a few 1000s of miles later and my CEL is on and cylinder two is throwing the bad ignition coil code... Think I'm in for it again. I'm poor and disabled and this job is gonna kill me. Wish they'd just engineer a car by mechanics for mechanics for once instead of capitalist BS made to break hard to repair crap we have.

 

thanks for the part numbers, saved me a bit of time,
michel

 

You're welcome.

 

Just my opinion: do not buy Harbor Freight torque wrenches for spark plugs as this is a critical setting. Spend the extra $ and get a good small torque wrench, as it will be cheaper than rebuilding the engine if one of the spark plugs pop out.

 

Hi again Pyts hope all your engines are running smoothly! I took a break from this but I'm back into it now.
I'm going to take my case to our consumer affairs people over here, and I've nutted out a few things.. The guy defending his company's faulty service on my car said a few things that I discovered just aren't right.
He said it had to show rough running - but my engine probably didn't show many symptoms because the plug was still well engaged in the head when it blew out, there was a big chip broken out of the head at the spark plug port.
The plug gasket was not fully compressed which he said was because it sprang back into shape. The NGK distributor said once its correctly compressed it can't spring back, so it was never correctly torqued when they replaced the plug. There were a few other things he said that weren't right.
I'm not impressed this guy has tried to put one over me, so I'm going to make life less comfortable for him via the consumer affairs process. Maybe they'll be forced to pay up.

I noticed back in your post no 48 a couple of Honda maintenance pages with the old torque setting and the new higher setting. They show that Honda changed the torque spec, which I think the dealer service team missed when they changed my plugs. I tried to copy your image of the pages but they come out too dark and blurry. Don't want to be a pain but would it be possible to put those 2 pages up again?

 

You've got my support and I'll make time today, but there is an issue. Honda itself did not share record with me of the revised specifications. What I have is a Bishko service manual that shows the older specification, and I'm to understand that Bishko was at some point employed by Honda to make said manual, otherwise, why would they make it? It's not like these old CDs are sitting on the shelf in autozone.
Now, there was that old bulletin declaring that the torque value was increased, which I'll try and dig up again. I'll do a screen cap where I can, and if I can dig up that old dealership print showing the revised Honda spec, I'll do so. If I can't, I'm positive that either you or I could obtain the newer specification readily from any given dealership -- there's no way they left it at 13ft.lbs. They'd have a proper recall if they didn't update it.

Fun facts: i'm presently working on our tacoma's emissions system. They also had a recall for 2012 that didnt include our 09, but the deal was: their emissions system consists of an air pump and an electric valve. It pumps in fresh air directly from the pump to the valve, and the valve opens to let said air into the exhaust. The problem: They used a shit filter for the air pump. Less than shit.
When I got the truck, I thought there was wet garbage in the pump's little intake. I pulled it out because it was shredded.

Now, well, as of yesterday, I've got a sticky electronic valve letting air into the exhaust.
Dealer said I was on my own/not eligible for the 2012 "service campaign" that replaced the valve and pump, adding a newly designed/barely less shitty sheet material style air filter to said pump.

Thankfully, the online community was on top of it.
I cleaned the valve yesterday, and made purchase of my own shitty, but less shitty than theirs, filter. It'll be back on the road tomorrow. I'm just glad I caught it before the pump or valve burned from sticking open. I'd have been out $1,200 in dealer parts, or
$100-600 depending on my choice of aftermarket/scrap solution.

 

Thanks so much for that Pyts!
I have a good copy of the Honda 'Tech Line Summary Article' of October 2016 if that was the bulletin you refer to- it was a link on someone else's post on this thread. It's good for identifying the problem but doesn't actually spell out the revised torque settings just says 'be sure to use the torque specs in the service information'.
Anyway if you can find the other references that would be great, I'm sure Bishko and other manual publishers generally get genuine info from the manufacturers.

Ha who would have thought a big manufacturer would use a cheap and nasty part in their otherwise nice shiny machine!?
Hope your new filter does the job.

 

@DavidL Sorry if I missed something, but the revised torque spec for spark plugs is 20 ft. lbs. It's all over the Internet, but you don't have to trust that. There was a service bulletin if you can find it.

 

I've attached a PDF for spark plug removal/installation and inspection from the Bishko manual. It is watermarked for Honda, so there's that. Oh. that gave me an idea. I'm adding the index page that says it's Honda's property. Now that that's done I can go back to responding via mobile
Yet another idea!! I combined them into one file in hopes of lending credibility.

 

Thanks for that Pyts! It’s just what I needed for the original spec. Really appreciate you digging that up for me.

 

Yes thanks for that too Mister Coffee. I have seen it quoted but not on an actual Honda document which I probably need to make this challenge via a mediator.
I have a copy of the Honda ‘Tech line summary article’ from 2016 which explains the problem, but it doesn’t have the revised torque spec. There may be another Honda bulletin somewhere that I have missed, even after trawling for a while. The manufacturers aren’t quite as open with their service information down here as they are in the US.

 

I seem to recall seeing a Service Bulletin with the revised spec . . . but my memory is notoriously faulty. I'm surprised one of our very good 'Freakers here has added it to this thread. Maybe they will soon.

 

I also had the P0303 code on my daughters 2009 Fit with 140000km on it. I traced it down to a faulty ignition coil by swapping #2 and #3 coils. I noticed alot of sooty residue on the boots for #2 and #3 plugs. I read that the spark plugs were known to back themselves out so I checked them and #2 and #3 could be removed with just my fingers. I figure maybe there was some blow by and maybe that fried #3 coil pack.

I was going to just replace #2 and #3 coils due to the loosened plugs. The old lady previous owner had always had the dealer perform maintenance and I asked them for the records and the plugs or coils have never been done, so I decided on doing all 4 coils and plugs. Our local NAPA was asking $175 CDN each. For the hell of it I asked at the dealership and they wanted $310 CDN each!!! To hell with that. I hit up rockauto got 4 NGK coils (55.71 CDN ea) and NGK plugs (3.89 CDN ea). Everything done for less than one coil from the dealer.

I did ask the Honda dealer for the proper spark plug torque as there seems to be some debate. They were good enough to look it up in the updated service manual and it does say 20 ft/lbs. using a bit of anti seize.

 

Ooof, those dealer prices are frightening.
Great job finding a much better deal!

 

Yes there is a revised spec. I went to my dealership yesterday to ask them this and he looked it up in the service manual. He told me it is now 20 ft/lbs using anti seize on the threads.