2012 Fit Sport manual 214K miles

About 3 weeks ago we were driving and it developed a bad misfire and then threw a CEL and went into limp home mode (extremely low power.) We got it home, shut down, restarted and all was well (it ran fine, no misfire.) But I plugged in the code scanner and it was showing a misfire on one cylinder (I don't recall which one.) It was due for plugs anyway, so I replaced all four plugs and coil packs. Fault code went away.

(I don't know if that has anything to do with the problem I'm seeing now, but thought it was worth mentioning.)

Then car sat in the airport parking lot for 9 days. We picked it up the day before yesterday. It was fine on the drive home and the wife had it out shopping yesterday and it was fine.

This morning I was decelerating to a red light. It turned green and I got on the gas. The car stumbled like it was in 4th or 5th (it was in 2nd.) I put the clutch in, shifted out of gear and back (to make sure I was actually in 2nd) and the problem went away. Driving home this afternoon it started doing it again. Sometimes it would happen at freeway cruise...when I'd get on the gas it would lose power. I'd let off and get back on it and it would be fine. Sometimes it would happen when pulling away from a stop. Then it would go 15-20 miles without doing it. It did it with the AC on and with it off.

I checked and it is not showing any fault codes, even when I wait for it to do it then immediately pull over and scan for codes without shutting down, it's coming back clean.

With the engine running I sprayed carb cleaner around the joint between the upper and lower intake and between the upper intake and the throttle body to see if there was a leak...RPM's stayed stable so I don't think there's a leak there.

What should I check next?

 

Seems like you've checked some of the problem areas already. Too bad you don't have an error code to work from. When it is stumbling, does it seem like all cylinders are firing but inefficiently, or does it seem like a cylinder or two are dropping out? What does the tailpipe look like when it is happening? Smoke: black or white means different things. Does the tailpipe show any build up of soot?

Not questioning your scan tool but a second opinion (a different scan tool might have different abilities - noticed this when we had VWs) might be worth it.

An intermittent loose wire - drive in on some rough road to see if you can completely disconnect or reseat a loose connector.

This is a hard one to figure out.

 

I eventually took it to the dealership. The tech, a master tech, and the factory wound up working on it for nearly 2 days.

Egr removed and cleaned. No change.
Fuel pressure tested ok.
injectors tested OK.
Cam position and throttle position relearn.
They even pulled the clutch cover and checked the flywheel because one of the techs said they saw a similar issue when a customer changed the clutch and didn't resurface the flywheel which was badly warped. (I recently changed the clutch but I did have the flywheel resurfaced.)

Eventually they noticed that the brake switch was flapping (on and off) when the problem happened. My scan tool software didn't show that level of detail.

Because of that thing with Toyota a few years ago where throttles were sticking and people were crashing because they were too stupid to put the car in neutral or turn it off now all cars cut power when the brake is applied. So...brake switch faults closed and the computer cuts power.

To their credit, the dealership only charged me 1 hour of labor for the diagnosis which is what they originally quoted me plus few bucks for the switch.

I need to look into better scan tool software. I'm using an OBDLink adapter talking to Torque Pro on my tablet. I suspect the issue is that the torque app is the limiting factor and I need to find something that'll run on my laptop. I had a good app on my laptop years ago (windows xp) but need something that'll run on win10.

 

Thanks for the update. Always found diagnostics exhilarating and maddening at the same time.

 

Indeed.

I've been commuting 120 miles a day and making several cross-country trips per year for most of the last 15 years and I do all of my own maint. The only thing I go to the shop for are tires...and I take the rims to them because I don't want some idiot overtorquing my lugs (I've seen them do it a thousand times to other people's cars.) This was the first time in 15 years and God knows how many miles that I was stumped.

It figures that it was some idiot-proofing BS that nailed me rather than some actual, useful part of the car going bad.

Anyway...we got the car back and all seems well, so I'm happy.

 

Thx for the update

 

Hello Bounce,
I had the car engine either shut down on me while I am slowing down for red light twice, and while I am backing up (reverse gear) slowly into my garage.
Just like you, no error code at all. The engine sometimes was unable to restart right away, but sometimes just restart again...
Now I think about it, maybe, I was able to restart my car because I push the brake while I am starting my car...
How did they notice the brake switch was flapping? Did they use their Honda Diagnostic Tools?
Thank You,


Also, how did they solve this problem? Did they replace your brake switch or just adjust the position of the brake switch?

Thank You

 

Using the Honda diagnostic tools, they saw the brake light switch toggling on/off during the timeframe that the problem was happening.

The fix was to replace the brake light switch.

It's a cheap part...around $10 and easy to replace. I'd be inclined to just replace it if you think that might be the issue.

 

lol. We had a Toyota with that sudden acceleration problem. It happened to us probably a half-dozen times while still in Park. Scared the absolute daylights out of me so I can understand how people froze in fear.

I never figured out what happened but several possibilities: defective design, the mat got stuck on the accelerator pedal or foot got jammed.

 

Hi Bounce,
Thanks so much for your very quick response, I really appreciate it.
The only problems I am facing right now is, there are 4 different Parts Number listed for the brake pedal switch at online Honda Parts store such as Bernardi Parts or Majestic Honda,
so just to be safe I plan to order at least 2 parts with larger part number (the last 3 digits), because I think this last 3 digits reflect the latest revision.
Thanks again

 

you coooouuuuld call a dealership, tell the person at parts your vin, and get exact P/Ns if you wanted to save yourself some shipping woes. Then just turn around and look em up online!

might replace mine now, just cuz. Who wants flappy parts in their car.