Two weeks ago I got a manual 07 Fit sport with 155k and joined the forum. Yay! Now, though the car is getting a check engine light and I was wondering if anyone out there can help me diagnose it. I've tried a few of the common solutions already.

When I got the car, it threw no codes, but would stall when cold when you were driving and put the clutch in (RPM drop from ~2k to zero; sometimes would rebound, sometimes stall out). That problem seems to be attributed on this forum to typically valves needing adjustment. I took the car to my shop and they adjusted the valves for $110, and they said that the compression was low beforehand, so that yes, they thought it was the valves causing the problem. They also were worried about the injectors and recommended a $170 injector cleaning, which I declined. That fixed the stalling problem; whenever you put the clutch in now, RPM's drop to their ~800 idle speed and stay there, hot or cold.

However, shortly after the valve adjustment, the car started throwing a P0302 code (cyl 2 misfire). I got a new coil pack (the original was old) for it and spark plug just for cylinder 2. The old NKG Iridium plug was blackened around the white part and the electrode was blackened and bent at about a 30 degree angle to vertical. It was gapped to about .032. I figured that as bad as that old plug was, that would fix the code. However, it's still giving me P0302 20 miles later.

Specifically, the code light blinks (indicating active problem???) when it's idling especially after reving the engine a lot. Also, when the engine is hot it seems to make some chatter (valves?) at RPM above 3500. In general it runs well, though and seems to have good power at the higher RPM's, but the idle is a little rough.

I'm currently running Techron through it to see if that helps, but it has not so far after about 30 miles.

Any thoughts? I feel like the blackened old spark plug is significant, but I'm not sure what to make of it. Any help would be much appreciated.

 

Why not replace all the plugs, reset ecu, then drive normal for about 15-30min to see if it trip the CEL again. If it does, check the other 3 coil packs. Compare the to the one you replaced if you have it still. This will help more easily tell if other packs have failed. Wow once this all gets fixed, youll feel like you added a s/c'r because its def loosing power. Oh 3rd, How is you mpg's right now? That too is a sign.

 

MPG's were low for my first tank - like 26, however, that was partially before the valves and a good portion of the driving was mountains.

 

Try following this guys technique:

http://www.justanswer.com/car/5iu9d-...blem-worn.html

 

could be the fuel injector? or weak cylinder?
maybe try and swap the #2 injector with another

 

Maybe the valve adjustment for number 2 wasn't done properly. Because according to you, it didn't misfire before the adjustment. Considering you've already got the coil pack and spark plug replaced, the only other thing that I can think of is the fuel injector or improper valve adjustment.

If you use top tier gas like Shell, Chevron, or Texaco then there's a good chance your fuel injectors aren't clogged up.

 

Replace all coil packs with new, Honda OEM and new NGK OEM plugs. A bad coil pack next to one that threw the code can be culprit. ...best to replace all.

 

Hi all, thanks for the replies. I think the problem ended up being a combination of a few things, but now the code has gone off and idle has smoothed out some, though not all the way. So to summarize, including the problems from my original post, here's what I did and symptoms: I also talked with the dealer and learned a bit more about the original state of the car.
0. Before I bought the car, it was apparently running horribly; instantly throwing a code (the dealer tells me this now) so he checked one of spark plugs; looked fine, so he put it back, tried out two new coil packs and mixed them around. The coil packs didn't seem to him to help, so he put the factory ones back on and did the valve adjustment. The valve adjustment improved driving a lot, and apparently let him get a drive cycle in with no codes but I don't think he adjusted valves quite right. Also, I suspect he may have gapped the spark plugs short to mask the weak coil pack issue (plugs were all gapped .030-.035). And he was idling the car excessively before I drove it to bring it up to temperature before I drove it.
1. (as I bought the car) stalling after clutching the engine while cold; classic valve clearance symptoms, so I had the valves adjusted by a reputable 3rd party shop. This completely fixed the stalling.
2. P0302 code came up a little after having the valve clearances adjusted. The code would flash when the engine was hot and engine was idling, and would stop flashing when given more gas. So, replaced plug and coil pack 2 with NGK Iridium and a generic (advance auto) coil pack. Then started a bottle of Techron through the engine.
3. Same code problems persisted, so I posted this thread and changed the other 3 spark plugs and replaced the factory light pink colored coil pack boots with the $37 pack of four from Rockauto. This made the engine run a little better, and the code no longer flashed, but was still there.
4. On the second bottle of Techron through the engine (also been deilberately reving to like 6,000 rpm to clean out injectors better), the code has gone away and idle seems better. Not perfectly smooth, but good.

So in summary, I think the valve adjustment, coil pack boots and fuel injector cleaning all helped some, and that my original problems were a combination of the three issues. The spark plugs may have been fine gapped short as they were. Perhaps something in here is a red herring in terms of fixing things, but this is how I've perceived the changes in the cars performance. Hopefully things are now fixed. I'll update if I'm missing something here.

Again, thanks for the tips. It is nice to have a forum like this where helpful advice about common issues can be found. And it's nice to be driving a car that's relatively easy and cheap to work on in general.

 

Well, as it turns out I was missing something big in my previous synopsis. I had a bad valve in cylinder 2 and low compression due to it not seating right. The CEL went out for like 2 days (wasn't doing much idling during this driving), but then came back. I took it back to my shop, and they diagnosed the problem. I got a 2nd opinion at a local performance tuning place. They confirmed the bad valve would cause all the problems I had; namely that it would idle rough because the leaking valve wouldn't develop enough compression for the cylinder to fire at low RPM. However, under higher RPM, the greater volume of air and gas being put into the cylinder would make it less likely to misfire, and the engine would seem to run smooth. He said it was akin to the scenario of old big-block muscle cars tuned to optimum power at high RPM's that would "glug" at low RPM's. The optimal point to ignite the air/gas in the cylinder for high RPM was at a point where, at low RPM, the density of gas wasn't enough to reliably ignite the cylinder. Also, the combined misfiring and leaking of the valve would lower MPG to the high 20's that I was getting.

So I ended up getting a used engine (42k miles for $675) and had the local Honda dealership put it in for $1090. I got quotes from independant mechanics of about $900 and $1800 to do the engine swap as well. I shelled out the extra for the dealership just because it is an engine and I wanted to maximize my odds of it being done right.

To repair the valves on the old engine would have been about the same as the engine swap; 10.5 hours on the labor charts instead of 9; plus machining of the head and the new valves themselves.

Anyway, I know this is a rare repair. I can only think of a couple instances of bad engines on this entire forum that I've encountered (and I was searching a lot to figure all of this out). And when I checked completed auctions on Ebay, only 3 engines had sold in the last 2 months for the 07-08 Fit engines in the US. But maybe this will be helpful to someone in the future who is chasing these problems down. The compression test ended up being key to diagnosing the problem.