I am the original owner of an 09 fit. I've always done maintenance on schedule and taken good care of the car. My check engine light came on about 2 weeks ago, and the code was 4th cylinder misfire. After some reading here, I thought it might be the coils, as the car is at 80k. I replaced all 4 coils with densos, and used NGK plugs. After replacing the coils, the car ran better, but still seemed like it was misfiring at idle. At that point I thought it may be something inside the engine and I gave up and took it to the dealer. I had them do valve lash, and they recommended replacing the fuel injectors. I replaced all 4, as I plan to keep the car for a long time. The car ran noticeably better, but after 2 days the light was back on again and it was still 4th cylinder misfire. At this point I was thinking either vacuum leak or electrical problem. I tried the carb cleaner trick and didn't find anything. Thinking it was electrical, I took it to the dealer again. Now they're saying the valve on the 4th cylinder valve is bad and needs to be replaced.

Has anybody had a valve go bad with such low mileage? I've done all of the recommended services and changed the oil at 3k intervals and ran synthetic. I expected to get at least 150k out of the car without any internal motor issues, if not more. At this point I'm about $1300 bucks into this, and they want 3100 to put in a used motor. Not sure if its time to put my fit out to pasture or not.

 

These engines will last over 500K, ask JuliaNacho. If I were you, having done what I've done I'd do a relative compression test to see the overall health of each cylinder. If you have a dead hole then maybe start looking into more invasive work, but if they're all relatively close to one another start looking into errant crank sensors, or did you gap the plugs correctly, or try new plugs, clean the shmutz out of the throttle body, and if you're feeling really froggy find you a scan tool that can read live data. I've seen some bluetooth OBD readers for cheap on Amazon. I used to have one that would read all sensor info in real time. Fuel trims, timing advance, misfire counts in real time, ect.

 

Thanks for the reply/ I'm going to start by testing the compression on my own to verify. I'll probably get a scan tool as well, as I find it really hard to believe a Honda needs a rebuild at 80k.

 

Here in PA, USA, car part stores (Adv Auto, AutoZone, etc) will come out to you car with their scan tool for free. You can see / write down the codes, so you can verify later.

But, do you hear any extraordinary valve noise? Before doing the 'Full Monty' at $1300, I'd go back and check the spark plugs again. Make sure that they are still tight. Mine kept coming loose.

The other thing you could do to eliminate the possibility that it's a bad coil pack, you could number them and then move them to other positions. If the misfire moves, then you know that the plug / valve is good but it's the coil pack.

Did you save the old coil packs? They were probably still good and would have lasted 500k miles. If you think it's a bad coil pack, you could substitute one of those.

It seems like you've changed everything else.

A valve usually goes bad due to a lot of deposits that hold it open enough for the hot combustion gases to damage the valve or the seat of the valve. The other way is if out of adjustment and the valve never closes the whole way and allows the hot combustion gases to damage the valve or the seat. A mis-alignment could occur if the valve guide has excessive wear / valve doesn't seat / burns oil in that cylinder and again allows hot combustion gases to damage the valve or the seat.

Seems that you where changing the oil as required. Again, pulling the head is pretty drastic at this point. The coil pack and spark plug work can be done at home ($0).