The valve adjustment is for both intake and exhaust valves. Partial instructions are found here. https://www.fitfreak.net/forums/3rd-...learances.html
Pretty sure it's for the GK, but not positive.

As for carbon build up from direct injection it's on the intake valves.

From what I've gathered to avoid carbon build up you make sure you change the oil within specs, make sure the car reaches operating temperature when you drive it (avoid very short trips with a cold engine), and give it the old Italian tune up every once in a while (treat an on ramp like a drag strip).

 

The best video I've seen on the issue of direct injection problems is this:


There's a good explanation of the carbon build up problem. In 20 minutes he covers just about everything including oil quality, catch cans, walnut blasting and so on. I believe he also mentions why turbos are a really bad idea for a DI engine.

 

Awesome video. Thanks for sharing. Deleted my earlier post.

 

Good video.

Short version is what I already said, run good fuel and good oil as precautionary measures.

Proactive companies are either using dual fueling (Ford, Toyota, etc) or using built in oil catch systems (VW, Audi, etc).

 

oil catch can and some amsoil comin right up

 

I am surprised though at the lack of reports of problems with carbon build up. There has to be a lot of GK Fits with DI engines on the roads now which have built up a fair amount of mileage, and yet reports of carbon issues are relatively rare to date.

 

I have 125k on my 18 Fit and will be doing the walnut blasting soon. I’ve had check engine codes P0420 and P219A come on and off for 30,000 miles now(air to fuel ratio imbalance). I paid Honda for the fuel injector cleaning treatment but that didn’t help. They then diagnosed the issue as failed injectors so I bought a used set from a junk yard but luckily discovered this site and realized it’s probably dirty intake calves causing the issue.

Here’s a good how to video on walnut blasting, I just wish I knew if the N54 bmw vacuum adapter would work with the Fit.

Once the job is complete I will try to only use ethanol-free fuel to see if it helps.

 

Ethanol-free fuel will not help remove valve deposits by itself. The goal is to clean carbon from the INTAKE TRACT.



Have you considered using an intake cleaner containing P.E.A. (which is the 'active ingredient' in Techron)?

Do this one tank of gas, BEFORE doing an oil change:

Use the Techron (or equivalent) fuel cleaner AS DIRECTED. (Remember you have a small gas tank) (This is to clean injectors internally)


Then, use an intake cleaner. I use CRC Intake, Valve, & Turbo cleaner


This is ANOTHER chemical that you should USE AS DIRECTED. Here is the 'official' instruction video from CRC:



Then, change the oil (as those chemicals will go into your oil and contaminate it).

There are also videos of intake tracts before & after on YT. I'll let you find them. Better yet, buy (or rent from AutoZone) a borescope and show us the difference.

PS: From what I have read, Honda's Direct Injection design (that sprays the valves as they open) does a LOT to prevent carbon buildup on valves...unlike BMW and Hyundai/Kia GDI engines.

 

Oh yeah, after I first got my P0420 and P219A codes over 25,000 miles ago, I ran 3-4 bottles of the stuff and even paid Honda to do the foaming injector cleaning, but the codes keep coming back.

I took the intake off and the valves don’t look so bad(?), so perhaps Honda’s diagnosing of bad injectors is correct. I have a set of used injectors from a 2015 that supposedly have only 30,000 miles on them, but I’ve never replaced injectors and from what I’m reading the system is under a lot of pressure and the job might get messy.

Here are my intake valves on my 2018 Fit with 125,000 miles:

 

It seems, 9 times out of 10 when a GK has a problem, it's the injectors. Quite a few owners pop up on the various FB Fit pages with injector troubles weekly.

2015 injectors would not be a wise move. Those were covered by a TSB for the failures and the part number revised.

 

I’ll be doing the walnut blasting tomorrow but the snag I ran into is with the Remote Starter Switch. I hooked one end to the + battery terminal and the other to the only connection I can see to the starter (it has a blue bolt), but can’t get the engine to turn over when pressing the button. There’s probably a second connection I need to connect to that I can’t see, but it’s really tight by the starter and I can’t get a hand in there. Any tips?

 

+1
The injectors were redesigned I believe in early 2016 to go with that new part number. As far as I know cleaning injectors to solve a problem is a waste of time. You either replace them or not. I don't recall Honda itself ever recommend cleaning in any TSB or whatever. Dealers of course might recommend cleaning ($$$) knowing it's bonus money in their hands before doing the eventual replacement.

 

If your goal is to rotate the motor for valve cleaning, all Honda's I know of have an access hole in the passenger inner fender. That hole leads straight to the crank pulley bolt where you can turn the motor over by hand.

 

Thanks for the advice, you’re right it’s probably not a good idea. The best I can do for now is to clean the intake valves with the walnut blasting and see if that clears the P0420 and P219A codes, otherwise my issue may indeed be the injectors.

 

That requires pulling the spark plugs, correct? You know, it might actually be easier for me to pull the plugs than find this starter wire.. unless, could I connect the Remote Starter Switch to the relay?

 

No need to remove the plugs to do it manually. Plus you can control it much better vs. bumping the starter and hoping it lands where you want.

If the crank pulley is on the passenger side, turn it clockwise. If on drivers side, counter clockwise. GD and GE Fit's are on the passenger side. Never worked on a GK so I'm not positive of location.

Other idea...might require some serious Internet searching but some cars will let you crank without starting. On Ford's you can do a key sequence and then hold the throttle wide open and hit the start button. That tells the ECU to crank the engine, but not send fuel or spark. Maybe Honda has that built in as well.

 

Good stuff, thank you GAFIT

 

It’s in the driver side and much easier than I imagined. 19mm, cranked it and the two valves closed and two others opened. I’m in business for tomorrow’s walnut blasting.