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Carbon Buildup on FIT Earthdream Engine Valves @ 52K--Input?
3rd Generation GK Specific DIY: Repair & Maintenance Sub-ForumThreads discussing repairs and maintenance you can do yourself on the 3rd generation Honda Fit (GK)
I don't like additives of any kind. They either do nothing, or they do harm (gum things up). I do use Chevron gasoline, which has Techron already in it. Most premium gasolines have detergents already in them.
Of course, lots of people use additives, and lots of people swear by them. If you can find a site like Bob Is the Oil Guy, and you are willing to put in the time, you can figure some of this out for yourself.
Same here, I've only pumped Chevron 87 octane in my Fit and 91 octane just about every 10th fill. I'm getting about 31mpg but I'm guessing the mileage loss is from my bicycle roof rack. I haven't tried using Techron fuel system cleaner but BMW rebrands it with their label.
I have 125k on my 18 Fit and will be doing the walnut blasting soon. I have had check engine codes P0420 and P219A come on and off for 30,000 miles now(air/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 valves causing the issue.
Here’s a good how to video in walnut blasting, I just wish I knew if the N54 bmw vacuum adapter would work with the Fit. https://youtube.com/watch?v=qnjeq715wKM
As far as what fuel to use - It’s not “top tier” to look out for, it’s ethanol-free that we should be using. Check out this Consumer Reports article from 2015:
”Some carmakers, including BMW and Kia, have issued technical service bulletins (TSBs) to their dealers recommending that drivers use only name-brand detergent gasoline—without ethanol additives”
I just purchased a 2008 535xi wagon N54 with 69k miles and on my to do list is a walnut blast. Lots of information on the web and its effectiveness for DI. My friend recently got it done on his 335i and it's day and night, performance has come back to life. Cylinder 2 was misfiring even with a new spark plug and coil pack, but has been resolved since the walnut blast. BMW fuel system cleaner is their relabeled bottle of Chevron Techron.
My 2016 was trouble free (except for the starter button issue) until just out of warranty.
All along, I bought tier 1 gasoline.
Early on I installed a catch can.
Did oil changes promptly using synthetic oil.
Being a slow small car, I was always gentle on the throttle.
Since day 1, I used Techron additive regularly.
Just out of warranty, it started hesitating during acceleration. The dealer wanted approximately $2000 for injectors & fuel rail. I told them to appeal to Honda for a good will repair.
They lowered the price to $700. This fix had the "New and Improved" parts. All was OK for a year, but now it's starting again!
Reading on this site and others about the issue, I saw the comments about running the engine hard periodically to clean carbon buildup.
Starting 3 weeks ago, during my drive home from work I floor it up close to redline on the freeway entrance ramp. Other times where I can, I accelerate hard from stops.
I have to say the car is running MUCH better. Almost normal in fact.
I think driving too easy does add to the carbon buildup (without looking inside) and driving hard keeps it clean.
My recommendation - Drive it like you stole it.
It's been over a month since my post on the hesitation during acceleration and I wanted to give a quick update.
As I wrote, I've been letting the car rev up from time to time close to redline while accelerating. No more hesitation at all when driving!
IMHO - the gas brand, gas octane, catch can, and additives did little to nothing to prevent or cure the hesitation. I always used to drive being easy on the car and see how much gas mileage I could squeeze out. I believe somewhere I was getting buildup (valves, tops of pistons, or even the catalytic converter which I've read has been an issue too). Pushing the engine made the difference over time, and in reality since I didn't floor it constantly, over time it didn't affect my gas mileage driving like this.
For me anyway, the proof is in how consistently smooth it accelerates.
@16FlaFit: Thanks for the update. It is valuable information to have.
I am not aware that driving these cars up to redline is going to hurt anything. It's very interesting that driving your car the way it was meant to be driven solved your problems. Happy news, indeed.
You need to worry about it on your intake valves but not on the throttle body. And you can mitigate the buildup on the valves with a pcv catch can.
Also fairly regular use of an injection cleaner like B&G 44K, 0w30 oil instead of 5w30 and top tier gas...so I read. I'm starting to think a catch can is a good idea for ANY engine.
Not bad for $30 odd but it needed a few things. Rather than having to unscrew the whole bottom, I drilled and tapped it for a drain bolt (with an O ring). The dipstick was a nice touch but I figured any oil would scrape off as I removed it, so I filed a flat in it. There was only the entrance baffle and I wanted more baffling for oil to condense on. I made one out of a piece of scrap aluminum and screwed it into the lid. I put a little silicone grease on the O rings for a better seal.
I used this this stuff "BG" at 60K and can't really tell if there is a difference in performance?
I empty the tank and put the BG in, fill it up, and drive it down to empty again.
A shop owner in Beverly Hills told me that is what he uses in his client's Ferrari's and Maserati's on every service so I figured then good enough for Honda?
What do you think?
Every 10K or 20K miles?
Waste of money and time?
B&G is well thought of by the cognisenti. I would say 2-3x per year, depending on how much you drive. In between (like every oil change I use Chevron Techron.
B&G is well thought of by the cognisenti. I would say 2-3x per year, depending on how much you drive. In between (like every oil change I use Chevron Techron.
I talked to the mechanic we use. He recommended at least Chevron Techron every 4 tanks on direct injection engines (but likes B&G 44K as well).
I have a catch can in my 07 Accord V6, and it's port injection. Keeps the intake tract very clean, there is still EGR of course.
I put a can on my wife's 2014 Accord a bit over a month ago. Just for giggles I checked today. No more than a a couple drop's worth of oil in it today. Must not be much blowby in the crankcase, which is good. The car has about 65K on it, at least 50% freeway.
I put a can on my wife's 2014 Accord a bit over a month ago. Just for giggles I checked today. No more than a a couple drop's worth of oil in it today. Must not be much blowby in the crankcase, which is good. The car has about 65K on it, at least 50% freeway.
Mine caught a ton, 100mL per oil change. That said, most of it was gas - during winter, so cold starts. It should help the gas dilution issue, which is an added bonus.
Mine caught a ton, 100mL per oil change. That said, most of it was gas - during winter, so cold starts. It should help the gas dilution issue, which is an added bonus.
Update: after more driving I found maybe 100cc of oil with crud in it. Interestingly, my wife's 4 cyl Accord has direct injection but the V6 model has port injection!
