Finally plagued by the loose spark plugs
 

I bought my 2009 three months ago now. These forums had me so worried about this problem, that two weeks after buying the car I replaced all the spark plugs and coils. Torqued the plugs to 16 ft-lbs.
I removed the cowl, didn't just reach behind. Glad I did because 3 different clips were broken from the dealer doing the valve adjustment..

Mine had the OEM NGK IZFR6K13, same as I replaced them with.
$35 (for all four plugs):
Ignition coils were $40 a piece (so $160 for the four):

Does it seem worth removing the Cowl to do the plugs?

I have to do mine at some point....... And what about the coil packs, How long are they considered to last?

I don't see how you can get a torque wrench in there without removing the cowl. Maybe you can, but I couldn't with my harbor freight torque wrenches! ;)
If you aren't using a torque wrench then sure go for it (edit: keep in mind the oxygen sensor wiring towards the far plug can be a pain).

With regards to the ignition coils I've lurked this site for years before posting and buying a Fit. Many people here actually get bad coils before the plugs go, because the plugs are such high quality metal (iridium).

just pull the cowl. the first few times i pulled the cowl and thought about how much of a pain it was. but the last time i checked my plugs i decided to do so without removing the cowl, and i can tell you that it was a nightmare trying to maneuver a torque wrench in there and i have little girls hands to top it off. literally took me twice as long and caused 10 times more frustration than removing the cowl. the next time i check mine will be even more fun since i now have a cusco front strut bar which is bolted to the cowl. :D

i recommend everyone use a torque wrench on them to know what they are spec'ed at. unless you are a master who for some reason does spark plugs every day all day and can tighten them by feel, you will never get it right especially with extra resistance of a new crush washer. other cars that dont have the ejection problem you can do the 1/4 turn method just fine, but even when torquing the plugs on these cars, im learning they are prone to loosening.

personally i went a bit tighter than the recommended 16 lb ft. and did 20 lb. ft. When i checked them after about 5000 miles after install, either plug #2 or #3 was a pound or two loose. (Denso IK22 recommended torque on aluminum = 15-22 lb ft)

it sucks knowing these have this potential problem and how inconvenient they are to check. i havnt figured out what a good interval is to check them yet, but im definitely a bit paranoid about them.

Listen to Eulogy.
Mind what you have learned. Save you it can!

And these are the clips that you should have before you start in case you break them.
hondapartsnow:
90602-TK6-A00 (white clip that holds the little piece on the edge of windshield) 2 clips total
91501-SL4-003 (2 black snap ins on either side of the cowl)

amazon:
90602-TA0-003 (green/blue clip that holds the main cowl) There are 9 clips on the underside.

Bunches
 

Bunch of good info already posted up, very little I'd like to add. The manufacturer's torque spec for the plugs is 18ftlbs. In fact, I believe ktc/nepros (oem tools manufacturer) sells a torque wrench specifically for spark plugs thats pre-set to 18 ftlbs. Check out frankstools.com for the imported goods, owner is a really cool guy and former master sergeant from his army days. I picked up the non marring ktc trim tools and the ktc plastic clippy removal pliers (those two parallel lines on the heads of the clips actually indicate where to fit the jaws of said pliers to remove them without breakage, though that doesnt apply to the bright blue clips,) matching hondas P/Ns.. he also sells said torque wrench and a myriad of tools that just dont exist in the american market, plus the prices are pretty much on par with husky/cobalt/craftsman
​​​​​
+1 for the IK22s. According to an old article from super street back in like, 09, they (and kraftwerks) made a claim that said plugs resolve a hot spot in the cylinders.
http://www.superstreetonline.com/how-to/project-car/htup-0910-project-2009-honda-fit/

oh, and i mean absolutely no disrespect when I say this but please be leary of those harbor freight torque wrenches.. i could make a necklace outta the snapped bolt heads i've aquired thanks to them not clickin. I wouldnt trust their calibration when it comes to torquing something prone to coming loose.

I agree you got to be careful with the harbor freight torque wrenches. Most reviews seem to have the opposite problem that you've experienced. They tend to under-tighten by a foot pound.
After I used them I checked all of them with a regular wrench to be sure they were all tight. Mileage may vary. For me I just can't spend the money on more expensive torque wrenches when I'm only maintaining one car. The one you were talking about pre-set to 18 ft-lbs is $150. My set of three from harbor freight was $35.

Now in terms of what you are saying about 18 ft-lbs. I'm a little confused. Honda recommended 18 N-m, which is 13 ft-lbs (for both NGK and Denso), then later I believe they said do it to 15 ft-lbs because of the loose spark plug problem. I've never saw anything that said 18 ft-lbs from the manufacturer other than some general guidelines based on plug thread diameter on other websites. No torque was listed on the plug packaging, just saying to use the car manufacturers torque specs.

You're right!
 

You're totally right, I'm the jerk here, apologies. I've been torquing to 18ftlbs.
https://cimg8.ibsrv.net/gimg/www.fit...7598f6b5a9.jpg
a chevy I've been workin on that also has aluminum heads is 18ftlbs, prolly didnt help.

this is the torque wrench I've been using for precision stuff: https://www.amazon.com/gp/aw/d/B000I1Y48U/ref=oh_aui_i_sh_in_o0_img?ie=UTF8&psc=1

​​​​​its crazy pricey, but i was able to get my hands on a lightly used one for 115, and it came with paperwork verifying the calibration n such.. but she dont ratchet.

as for the funny spark plug wrench, I didnt mean to recommend that one so much as defend my position on 18ftlbs as a fairly universal torque for plugs. I personally havent bought it yet, but theres a gap in my cobalt torque wrench set between the inch pound and foot pound wrenches. none of em cover 16-20ftlbs. Since this torque spec is also a common one for brackets and such affixing to engines (based only on my experience, hardware that fits between a 12 and 14mm socket size that isnt under stress, say, a throttlebody) it seemed like a fair purchase to not have to set the torque.
The one on frankstools is made by Koken and is 87.65 and currently on sale for 74.50. Youll see the discount if you add it to yer cart.
https://www.frankstools.com/kosppltora37.html Still, not a worthwhile investment for most folks but I think its cool. Speaking of unnecessary things, check this out.
https://www.frankstools.com/metoexdr38dr.html

in regards to the harbor freight stuff, i typically double, or if im spaced out, triple check torque on bolts, and with the wrench i had from them it would keep turnin on the second and third go then *pop*.. i wouldnt damn anyone for using them, cant beat the prices, i've just broken so much stuff and eaten so much humble pie that i had to buy new clothes.. now all the would be fun money goes into tools.
i certainly wouldnt advocate everything from franks as you can often do near as well for far cheaper, but he's the only shop i've found thats home to the real japanese ktc stuff at their retail prices.

sometimes just knowing a kind of tool exists opens up ideas for jobs you didnt think you could do yourself

I've been plagued with this problem for years, and I tightened it twice this week. On Tuesday I ballparked what felt good, and bought a torque wrench online. The engine code came back on again today, so I tightened it to 18 lb-ft. I'll post when I need to tightened it again so you know how long mine lasted. I should mention this cylinder was HeliCoiled 3 years ago, so that may lead to more issues. I'm considering having the head replaced.

not to be a jerk...but im surprised you just went by feel especially after having the cylinder helicoiled.

which cylinder is your problematic one?

if i remember correctly, all of mine were fine except #3. which was just a hair loose.

let us know how yours holds at 18lb

I'm with stupid
 

Such a bummer, man. i'd throw a +1 on the new head idea, when its reasonable to do so.
​​​​​​Heres my experience with an ejected spark plug and helicoil, not on the fit..
https://cimg3.ibsrv.net/gimg/www.fit...5429e4e227.jpg
Here you can see me poppin my cherry.
https://cimg1.ibsrv.net/gimg/www.fit...b4af4f7478.jpg
You can see a crack there between the intake port and valve. This was the same cyl that ejected the plug.. not sure if the chicken or the egg came first.

I'm not offended, it was by necessity. I didn't have a torque wrench and I couldn't buy one for $90+ when I knew amazon had it for $25. And I still needed to go to work the next day.

Cylinder 3 is my problem child. the rest of my cylinders have been fine. I'm planning on having a mechanic do a compression test and visually inspect the head to see how bad the damage is. I'll update the forums once I know. If the CEL doesn't return I'm going to wait until I can have it done by the family mechanic (I'm cheap, and he'll do it for free labor.)

It wasn't nearly as bad as @Pyts 's ejected spark plug, but I know if I ignore the P0303 for too long that I'll have a similar looking head.

Not to dawdle on an off-topic sidebar, but torque wrenches are in calibration and accurate until they are not. Therefore, they need to be checked and recalibrated regularly, which is a pain in the tush, if not an impossibility, for most of us (who are not pro mechanics). I used to use a Snap-on torque wrench on spark plugs, a beautiful little expensive item. On wheel lugs and big stuff, I used torque wrenches from Sears. All of my wrenches went out of calibration eventually. With regard to tightening by feel: a spark plug has a crush washer on it. I tighten until I feel it crush. Stupid idea? Maybe. But it's been 30+ years of motorcycle and car spark plugs and I haven't had a problem yet.

CEL returned after driving to work (37 miles.) When i turned on my car to drive him P0303 came back on. Tomorrow I go to the dealer to find out about a valve adjustment and possibly get a compression test.

Any advice to minimize the cost but fix the car? I'm thinking of checking the fuel injectors myself. Any advice?

Kayy. That code is for 3rd cyl misfire. ​​​​​cant recall if we established that before. I wouldnt think valve adjustment so much as troubleshooting that code for you with their fancy HDS tool. ​​​you could then just do the wrenching yourself based on their ~80-$120 diagnosis. at least we could then point you in a direction.
Oh... now this may be controvercial as hell, but.. you could use teflon threadlocker to seal in your plug until you can afford to fix this. I'm quite confident it could keep your plug from loosening. Just make sure to inspect said plug first and clean the threads with some rubbing alcohol.

**maybe the sh1t keeps loosening because the helicoil is a different kind of metal and is heating and cooling at a different rate.

would you guys recommend using anti-seize compound or anything to help
out the threads.

thanks

that makes the most sense. It always seems to happen after my car cools off during work. Is there anyway to help minimize this?

My guess
 

You can talk to a mechanic, or better yet a machinist. My uneducated opinion would be to get a new iridium plug or plug set (they give the most mileage) and use teflon threadlocker to hold it in there. I really do believe it could do the job.
this ideas from way out in left field but I wonder if a copper adhesive spray like what can be used on a head gasket could be bwneficial here. The idea behind it, *to my understanding*, is to prevent the same kind of issue for cast iron blocks and aluminum heads.

Sorry it took so long to get here, aint the sharpest tool.

I wouldn't use anything. Anti-seize would make it easier to get out, which would be bad for the thread issue.
I also wouldn't use loctite unless this problem keeps happening, after which that doesn't work you do helicoil then/or a new head.