Hello all, I have been a lurker here for some time. Never made and account, just usually use this site for info, as I have ever felt the need to post....until now.

I have a 2009 Sport (auto) with roughly 121k on it. The car seems to be in limp mode, won't go over 10mph. I've had i scanned and it's reading misfire in cylinders 1,3, and 4 as well as a random misfire code and a running lean code. At first I thought I had bad gas, but upon doing more research and seeing all of the horror stories about these cars having issues with spark plugs backing themselves up and destroying the threads, I'm starting to think it's more than just a bad (half tank) of gas). I changed the plugs a couple days ago, and 3 of the 4 plugs, while not finger lose, were not as tight as they should be. Upon replacing them, I could tell that they did not want to snug up, so I got them as tight as I felt comfortable while not spinning them completely. I got everything buttoned back up, and the car started fine, but again, after about 15 seconds of idle I had flashing CEL and it was running really rough, with the same codes, so I shut it off. I am about to go outside and to a compression test as soon as I finish this post. What kind of numbers should I be looking for in terms of good compression?

I need suggestions. I am fairly mechanically inclined, but I am ot very well versed in the Fit platform. Could I really have 3 bad coil packs all malfunction at once? Did I drop a cylinder? Have people had success re-threading the plug tubes? Am I losing compression through the plug tubes because the threads are trashed? Do I now have a boat anchor I paid 10k for? This little bastard is ALMOST paid off, and the thought of having a blown motor, inside a car that probably worth as much as the motor, just pains me to no end...I'll update the compression test shortly as I already have the cowl and stuff removed.

Any and all input is appreciated.

-Garrett

 

I would not assume a catastrophe. The codes and lean information help.

1. This could be underpowered computer. I might check the battery for proper voltage (or have a store do a test on it with their tester). I might also do a voltage drop test to make sure the major terminals and connections are not high resistance. Check general connections are not loose.

2. What are the codes?

3. Generally spark plugs need to be quite loose before the engine blows them out and destroys the head. If the old plugs were not finger loose and took many turns to remove and the threads seemed smooth during removal, that is not bad.

How many turns did it take to remove the plugs?

What was condition of each plug? Color? Damage? Wet? Dry? Amount of contamination? Photos will help. [maybe you would like all to be dry and have a very thin coating colored light tan]

Did you torque down the new plugs or just use haphazard estimate? That matters.

What new spark plugs did you use?

4. What was the condition of the coils? Ideally all long rubber shafts going into the head should look like clean, new black rubber. Do you see signs of heat damage, smoke, melting, etc.?

The coils can be damaged by heat escaping cylinder via loose spark plug. Or old spark plugs that have increased resistance (e.g. wide gap or lots of corrosion). You can test the coils for damage rather than dropping cash.

 

Also, did you clean the threads and seat of the head before inserting each new spark plug? If the old plugs were slightly loose, deposits from the cylinder combustion and heat will migrate to the threads and seat. That could make the new plugs a bit less smooth entry.

How many miles have you owned the car? Were the old plugs from the factory or did someone reinstall. Trying to ascertain if there is a possibility of prior head damage from loose spark plugs or from a rough mechanic inserting new plugs.

 

Since you have the cowl already removed, you might carefully check that the plugs did not loosen themselves during the 15 minutes they were in the car.

I don't think this is a compression issue to be frank.

Have you adjusted the valves? That is required at 100k miles.

 

1. The battery is at 12.5 volts, about 1.5 years old. I have checked all obvious connections, can't see or feel anything out of the ordinary

2. I do not currently have access to the scanner, so I do not have the exact codes on hand. I do remember it said misfire in 3 of the 4 cylinders ( 1, 2 and 4 if i remember correctly), random misfire, and engine running lean.

3. They were certainly not finger loose, but it took very little effort with the wrench to get them free, I can currently only get one of the four to actually snug up, the other 3 feel as if they are spinning. I did not clean the threads. I do not have access to a torque wrench at the moment, but I can go to my dad's and get one in the next couple days and get one. I used brand new NGK plugs part No. 6774. The plugs were dry, and had the thin coating light tan you spoke of.

4. Coils looked decent, although each one had very light grey coating on the bottom where they made contact with plugs. Rubber was still supple. Not cracked or dry rotted. I could not see any obvious signs of excess heat.

I bought the car used with roughly 60k on it. I will admit, I have not been super on top of maintenance other than oil changes and air filters. I have no idea if the plugs or coils are factory. The plugs are easy to get in and out.

Thanks for the quick reply. Basically I am looking to get this thing back to normal so I can trade it in...which I was preparing to do in the next couple pay checks...this is thing broke one me at THE WORST possible time...

 

Compression was as follows:

Looking at the motor, left to right, with average of 3 cranks per cylinder. I am going to re-test 3 and 4 as I think my battery was getting weak in the 20 degree weather.

#1 223
#2 210
#3 165
#4 171

I have not adjusted the valves. I do not have the know how nor the tools to do so, let alone pay a mechanic to do it.

 

I think its quite possible the threads are toast... but, having gone through the issue on my #2 cylinder, I would suggest trying out the re-thread inserts.

If you go that route, I would suggest a number of things:

- Don't use helicoil (specifically, the coiled wire), use the "time-sert" style insert.
- Use the insert that has a "shoulder," avoiding the ones that are "knurled" or require a tool to expand it.

The reason for both of those suggestions is... both helicoil and insert without the shoulder don't have anything to stop you from going too far into the cylinder. You want the top of it to sit as tightly and/or flushed at the top of the cylinder's own threads (where the spark plug would've sat) to keep a good a seal as possible.

Personally, I think there are also other issues with helicoil... because of its coiled wire nature making it easy to insert, it gives rise to the possibility it's easy to unintentionally remove also if the spark plug manages to catch the top end of the coil.

- Use threadlocker (something like red Loctite 271).

The goal is to install the insert as permanently as possible. Threadlocker might help with helicoils... but depending on the quantity used, it could just as easily seep between the coils and lock onto the spark plug if they're installed soon afterwards.

- Do work on all affected cylinders... or just all cylinders, period.

I actually had issues with #2 AND #4 cylinders, but only worked on #2 as it was the one that gave the most obvious issues. I ended up forgetting about #4... until a few days ago. My idle isn't as smooth as I would like it to be, but I'm not sure if its just the weather or the cylinder issues popping back up. If its the cylinder issue, chances are good, it's #4. So, I may end up doing the re-threading there too.

Final suggestion...

- Possibly go with a long insert. Just long enough to cover the threads on the spark plug.

The insert tool kit I bought came with four inserts of varying lengths... two of which are the real choice. Either the one that is the full length of the threads on the spark plug... or the one that is shorter and just enough for the threads in the cylinder. The threads in the engine only covers about half of the threads on the spark plug. So then, you might be wondering what the deal is. As far as just threading goes, either choice is fine. In my case, I chose the shorter one. But having thought about it afterwards, I think it would be better to choose the longer one.

A short while ago, I put a guess as to why this spark plug issue is occurring, and I think its because the threads on the spark plug that go past the threads on the cylinder wall are exposed to deposits that can bake themselves on. When you remove the spark plug during a change, any deposits that are really baked in are likely to chew the threads in the cylinder as it comes out.

So, this is why using the longer insert would be better as it should cover all the threads, preventing any of it from chewing out the insert itself. And of course, the hope is that insert is securely locked in place and won't back out with the spark plug.

On the flip side, the insert should be hardened steel, or at the very least, not aluminum. So it "should" be harder to chew out anyway even if you use the shorter insert. Too many "shoulds"... easier to just use the longer insert.

 

Given all the effort and cost to rebuild the threads, make sure that is your issue. For sure when the spark plug blows out of the engine, you likely have a thread issue. If a plug does not blow out and is decently seated, I don't think thread issues are so common. But as @Goobers notes, the head threads on the Fit can be a problem.

Hopefully this is a valve adjustment issue, which is much easier and cheaper to DIY. The Fit exhaust valves can tighten and that can show as bad compression/misfire.

This guy recently had similar Fit issues (5mph limp mode, misfire). Valve adjustment at dealer this week resolved problem

https://www.fitfreak.net/forums/2nd-...ops-5-mph.html

This is video on procedure if you want to try. If you changed the plugs then this is not so much more difficult. Should take 2 hours or so. Also, even if you rebuild/replace your head, you will still need to adjust your valves. No guarantees here but personally I might start here. People with more fit experience may have more informed opinions. . .

 

Thanks for all the info guys. Rebuilding the head is not an option, I am not in the market for dumping more cash into this thing.

 

So what is your plan?

 

I have some bad weather coming into my area for the next couple days. I work doing snow removal anyway so I won't be working on it until Wednesday or Thursday. My current plan is to do the valve adjustment and try and clean the threads in the head, then get my torque wrench and try and get the plugs to tighten to spec. If that doesn't work I guess I will try and re-thread the head and go from there, unless you guys have better ideas.

 

Good luck!

 

Its dangerous to go alone

 

Take this.
also organize it as follows:
wiper arms, cowl cover, wiper motor, under cowl, spark plugs (can be done at this point or later), air box, intake manifold, valve cover.

SPARK PLUGS GET TORQUED TO 20 FTLBS! NOT 13
also you dont need to worry so much about torquing the wiper motor as its rubber bushings are easily smooshed, or the under cowl. But if you do I'd recommend 72in.lbs. for 10mm bolts.

 

Ok guys, so I have been advised by a mechanic friend to to a fuel pressure test before I go about pulling VC off and doing the adjustment, as he has replaced several fuel pumps on these cars, most of which were @ 100k+ miles. Do any of you have knowledge of where I'd need to access in order to perform the test? Is there access on the fuel rail? Also, is it possible that the injectors and/or the pump could have been damaged by running the car on low fuel levels?

 

Final Update (hopefully):

Turns out the culprit all along was the on board computer. I purchased a used one out of a wrecked car that had only 28k on it for $160, delivered it to my mechanic, and all the symptoms went away. The valve adjustment and plugs have made a difference as well. Much quieter, smoother shifting, better MPG. All in all cost was $500.

Thank you everyone for all of your help and input, I greatly appreciate it!

 

Awesome! Thanks for the update.