By on August 3, 2018

2014 Honda Fit 1.5 Engine, Image: HondaTTAC commentator KCFlyer writes:

Dear Sajeev,

I have a 2015 Honda Fit LX manual, purchased new. From day one I noticed a slight momentary hesitation under moderate acceleration when the engine was cold. I took the car to the dealer after a few weeks but they could not duplicate the problem. I dropped it off again and left it overnight, hoping a cold engine would allow them to experience the issue. No luck.

Fast forward 57,000 miles. Same problem persists and is reported to dealer via phone several times. The check engine light comes on. Dealer says the code means an #3 cylinder misfire. They say the fuel injectors are clogged and charge $1,300 to replace all four injectors. Honda of America throws in $1,000 of goodwill money because fuel injectors are not covered by the 60,000 mile powertrain warranty.

Two weeks later light comes back on. Same code. This time another dealer pulls the head and finds carbon buildup on all four piston heads. They clean up the engine, clean the throttle body and declare the vehicle fixed. Total charges paid for by Honda of America under goodwill claim except $217 for the throttle body cleaning. That was yesterday and I will know within days if the original problem persist.

Tech rep was awesome. He recommends I get the fuel injectors and throttle body cleaned every 30,000 miles. My question, what caused the carbon buildup? Does the buildup damage the engine even if later cleaned up? Should I dump the Fit? It is an awesome commuter. I average 44 mpg summer and 39 winter.

Sajeev answers:

My, how this issue has changed since our first(?) discussion back in 2012: what was once a measured discussion of the merits/pitfalls of de-carboning an engine is now a second nature, knee-jerk diagnosis (that’s likely accurate).

Engines have turned into carbon cokers and oil burners, and that’s our new normal when shopping for a new ride: Honda’s Earth Dreams are no different?

The usual reason for carbon buildup is two fold: the aforementioned changes in engine design and owner’s driving style.  Odds are if you rung that little L15B1 out to redline on a regular basis in lower gears (so you won’t get a speeding ticket) the modern direct injection setup would run clean as a whistle: no need for any preventative maintenance? Of course, the Best & Brightest have the final say.

But I like those shift-yourself Fits and you should keep it…preferably near redline in 1st/2nd gear just for fun. 

[Image: Honda]

Send your queries to [email protected]m. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.
 

Get the latest TTAC e-Newsletter!

Recommended

125 Comments on “Piston Slap: Earth Dreams of Carbon Buildup?...”


  • avatar
    theBrandler

    So let me see if I got this strait: Modern fuel efficient cars that we buy to supposedly save money on fuel, and to save the planet from the harm of using too much fuel, have to be drive like their stolen, NEGATING THE AFOREMENTIONED BENEFITS, to maintain stated benefits?

    BAHAHAHAHAHAHAHAHAHAHHHHHHHHHHHHH………AHAHAHAHAHHAHAHHHH!

    • 0 avatar
      Lie2me

      Even back in the old carburetor days we were always advised to “blow it out” now and then to prevent carbon build-up, apparently the advice is still sound. I find a can of Seafoam added to the tank a few times a year also helps

      • 0 avatar
        JimZ

        how is dumping something in the tank going to help? We’re talking about something building up on surfaces the fuel never touches.

        • 0 avatar
          Lie2me

          I was talking engines in general where carbon build-up is a possibility. Sajeev was suggesting it’s still important to “blow it out”. Sea Foam can also be added to crankcase oil to help with deposits elsewhere

          “When added to crankcase oil, Sea Foam Motor Treatment will clean and dissolve deposits from internal parts. To minimize or prevent harmful oil formations, add Sea Foam to crankcase oil before every oil and filter change.”

      • 0 avatar
        Add Lightness

        Italian tuneup.

    • 0 avatar
      dougjp

      Not only that, the fuel savings due to engine design that eliminates the ability to self clean, or clean with additives, causes maintenance costing many times the differential in fuel mileage gained? All to show some fuel economy number in advertising.

    • 0 avatar
      NormSV650

      The fossil are Dreaming to part of the Earth again and are leaving their current state to join others.

      The Honda fuel diluting oil is just now surfacing with the 1.5t.

      https://forums.edmunds.com/discussion/50438/honda/cr-v/new-cr-v-cold-weather-runs-rich-gas-in-oil-multiple-complaints/p2

    • 0 avatar
      f1tifoso

      the irony…
      It’s easy to say there’s plenty of ways to meet CAFE without spending a fortune but then reality comes in an slaps your stupid goals around to remind you what really rules

    • 0 avatar
      HotPotato

      Nothing new. Since the 70s mechanics have been advising people to periodically “give your car an Italian tuneup” (redline that sucker).

  • avatar
    ajla

    “He recommends I get the fuel injectors and throttle body cleaned every 30,000 miles.”

    “Engines have turned into carbon cokers and oil burners, and that’s our new normal when shopping for a new ride”

    GOLDEN AGE IS NOW!

    • 0 avatar
      JimZ

      any engine w/o port fuel injection (either gas or diesel) will have some build-up on the back of the valve head and valve stem eventually. This includes gas engines with either carburetors or DI, and all diesels.

      if you have *excessive* accumulation of deposits (like with VWAG DI engines) that means the manufacturer screwed up on the crankcase ventilation system and is allowing too much oil mist to be drawn into the intake. if your engine has a proper catch/separator trap at the PCV source, your deposits/buildup will be limited to a bit of fuzziness on the valve stem from oil seepage through the valve guides.

      • 0 avatar
        kcflyer

        This is interesting and was not mentioned by Honda. I will do some research to see if such a system is in place on the Fit. If so it must not be working well. If not hopefully there is an aftermarket mod. In any event the brief hesitation issue remains when the engine is cold.

        • 0 avatar
          KalapanaBlack7G

          BG makes an excellent 3-can GDI cleaning product. I have seen 150k+ Kia 1.6 GDI engines in which it is used every 5,000 mi with semi-syn oil that never had any issues related (misfires, oil use, etc).

          • 0 avatar
            ToddAtlasF1

            You’re talking about $180 every 5,000 miles for the BG three-step, which really isn’t as effective for a DI engine as their four-step is. BG makes great stuff, but DI doesn’t save $180 of gasoline in 50,000 miles, let alone 5,000.

  • avatar
    30-mile fetch

    “He recommends I get the fuel injectors and throttle body cleaned every 30,000 miles.”

    “I average 44 mpg summer and 39 winter.”

    Assuming this service runs $400 each time (since the throttle body alone is $217), then you are now averaging 39mpg and 34mpg. Which is probably what you’d get from a simple port-injected engine that wouldn’t have this issue. This sort of maintenance doesn’t fit the mission profile of a commuter car like the Fit. It’s like equipping it with a DSG that needs $400 service every 30K miles.

    • 0 avatar
      gtem

      I share this sentiment 30 mile. I get that the fit got a useful power and mpg bump, but for regular commuter cars and family vehicles and things like work trucks, I think manufacturers need to temper chasing the greatest numbers against overall running costs and durability/reliability, and even thugs like refinement. The newest DI Camry engine is noticeably noisier and gruffer than the previous port injected unit.

      • 0 avatar
        30-mile fetch

        We just did a 2000 mile road trip in our Camry with that “old” port-injected 2.5 w/ 6spd, and honest to God I don’t know what more is needed in a car like this. 33mpg at 85mph cruise, 36mpg at 65, no problems with multiple passing maneuvers on two-lane highways. The transmission is responsive, the engine is surprisingly refined even with throttle pegged to get around the RV chain. Sometimes the old stuff just works.

        Autojournos make a big fuss about rated fuel economy and the latest underhood technology, but the mpg and acceleration gains from CVT + DI + turbo are just too small in a midsize sedan to be worth any additional maintenance like this. 30K mile fuel delivery cleaning services on a B-segment economy car–I thought people bought Hondas to avoid this sort of thing.

        • 0 avatar
          slavuta

          John Taurus will jump out of bush now and tell you something.

          Other than that, I always said that Honda passed its prime. Their cars have as many issues as others.

          • 0 avatar
            30-mile fetch

            Well, I think my wife’s 2016 Camry sitting on a 15-yo K platform is still surprisingly capable and chose it over the equivalent CVT Accord that I found to be over-hyped, so I’m sure a lot of people around here would like to “tell me something”.

            I’m apparently hopeless. But valve coking and expensive injector fouling at least aren’t on my list of concerns, so there’s some consolation.

          • 0 avatar
            f1tifoso

            Both of the big Japanese auto makers have coasted largely since the 90’s on their reputation and after 2008 have fallen behind Korea and a resurgent US engineering…

  • avatar
    kcflyer

    This is my car. I will add that the second repair would have been over 2 grand if Honda of America had not helped out. So that’s nearly $3500 in repairs in less than a month on a car still under powertrain warranty. Bottom line, there is no fuel spray on the valves so carbon builds up, then breaks off and sticks to the pistons. I will start revving it higher per Sajeev’s advice and see what happens. Still inclined to dump it and worried the 2017 civic EX-T we bought will suffer the same fate.

    • 0 avatar
      Pete Zaitcev

      Find out of the Civic has additional port injection. Then you’ll know.

    • 0 avatar
      Trend-Shifter

      This…but most likely the issue is carbon build up on the intake valves that is restricting the air flow.
      In 2015 the Honda Fit was changed to direct injection, so this is probably the root cause.

      The temporary fix for newer cars with direct injection is to pull the intake manifold, make sure the valves are closed, then walnut blast the carbon off the valves and surrounding area. Not good as we would want a new engine to last at least 160,000 miles without ever opening it up.

      Now automakers are adding some upstream fuel injectors to work with the direct injectors to keep the intake valves clean.

      • 0 avatar
        JimZ

        dual injection also helps manage particulate emissions by using the port injection in situations where DI generates the most soot.

        • 0 avatar
          gtem

          Yeah my understanding is the dual injection setups were introduced primarily in interests of emissions and low-speed refinement/response, with the valve washing as a cherry on top.

          I guess I’d take that over the purely DI setups, but I still would simply prefer to have port injection and not worry about the highly pressurized fuel system of a DI motor to begin with.

          • 0 avatar
            MBella

            I’m surprised nobody has gone back to the throttle body injector for the secondary setup. The advantages of port injection over throttle body injection would be handled by the direct injectors.

          • 0 avatar
            gtem

            Hmm I’m not sure how well the fuel mist at the throttle body would clean the backs of intake valves either. Presumably intake-runner mount port injectors are the best at hitting the backs of valves with fuel mist before it gets super atomized and lost in the rush of air into the cylinder. I’d love to hear an actual powertrain engineer chime in on the matter.

    • 0 avatar
      TrailerTrash

      I don’t know.

      This is getting confusing.

      They say letting the engine rev for periods of time and lots of highway driving helps prevent this…but then again, they say nothing will.
      The revs make no difference since they cleaning is simply NOT happening by the fuel.

      I have 95K on my MKS 3.5 ecoboost and have no issues.
      However, most, 70 percent, of my drive is highway.

      I have only used 93 octanes.

      But they say nothing of what I am doing is really helping…so I worry long term.

    • 0 avatar
      Carroll Prescott

      Oddly enough had someone had a domestic car with the same issues you have with your Honduh, they’d have whined about poor quality and dumped it to get a Honduh (which will develop the problem).

      Funny how quality perception is predicated on the tolerance you have and the willingness to join the herd.

  • avatar
    MrGrieves

    Have had this same issue with a BMW. I can confirm 2 things work: The occasional “Italian Tune-up” and walnut shell blasting of the intake valves and ports. Intake cleaners, fuel treatments, etc., don’t work.

    As another person mentioned – the carbon is actually condensed oil vapors coming from the PCV system. Some folks have installed a vapor “catch can” modification coming off the oil separator / PCV tube to sequester the vapors before they deposit onto the intake valves and ports.

    • 0 avatar
      PrincipalDan

      That’s the real reason for all the “manual” modes and flappy paddles on modern automatic equipped vehicles – so you can rev the $hit out of it every once in a while./s

    • 0 avatar
      MBella

      Intake cleaners do work, but the engine has to be hot, and you can’t expect it to clean heavy carbon buildup. You would have to do it pretty regularly. Cleaning additives in the fuel can only clean areas they are exposed to.

  • avatar
    incautious

    use a tier one fuel such as Shell Exxon ect can help with that. And like the others have said the occasional foot to the floor on the highway helps a lot.

    • 0 avatar
      carguy67

      How does a Tier One fuel get to the backside of the intake valves in a direct-injection (only) engine?

      To the original question; I believe pretty much all new cars have ‘throttle by wire;’ i.e. the throttle plate is driven by a small electric motor controlled by the ECU. If there’s any balkiness in this motor or mechanism you’d get hesitation; my ’96 Ranger experiences the same symptom when intake gunk makes the throttle sticky.

      • 0 avatar
        Funky

        carguy67; For what it’s worth, I agree with you, my gut instinct is telling me it has something to do with the so-called throttle-by-wire system. Especially given it was happening from day one.

        • 0 avatar
          golden2husky

          Could be, but why would that have not been caught by the data freeze frame when the tech was doing their diagnostics? I would think that if you could feel it from the seat of the pants there would be no issue finding that hesitation…

    • 0 avatar
      Kenn

      People keep repeating this only partially-correct advice, but the additives in a “tier one” fuel will only keep the injectors clean, while doing nothing to clean the intake valves (which fuel bypasses in a direct injection fuel system). Only walnut blasting cleans the valves once carbon builds up from oil mist from the PCV system.

      • 0 avatar
        gtem

        FWIW Honda was claiming they had solved the lack of intake valve wash-off with clever valve timing that allowed for them to stay open long enough to be exposed to the swirling fuel/air mix in the combustion chamber and/or avoiding the worst of the combustion related carbon build up (the non-PCV oil vapor sourced stuff). Apparently this Fit is proving otherwise.

        • 0 avatar
          JimZ

          I don’t buy that; by the time fuel could “blow back” out through the valve it’s already mostly evaporated anyway. And gaseous… er, gas won’t really clean anything.

          port injection sprays liquid fuel on the valve head while it’s still closed.

          • 0 avatar
            gtem

            You’re not wrong Jim. I’m staying away from the stuff on any long-term buy for the time being. There are plenty of competitive engines making good power and economy without having to go to DI. The port injected 3.6L pentastar in my rental Pacifica got a fantastic (self reported) 29mpg in higher speed highway cruising, made great power, and sounded/felt great doing it.

          • 0 avatar
            Scoutdude

            Old school batch fire injection systems used to spray gas on the back of a closed valve but in modern Sequential fuel injection systems in most cases the fuel is only injected with the valve is open. At higher loads the length of the required fuel injection pulse can exceed the amount of time that the valve is open so they will start the injection event before the intake valve opens.

  • avatar
    Pete Zaitcev

    This video may be on topic for Mr. KCFlyer, and so worth 19 minutes of his/her life to watch it:
    https://www.youtube.com/watch?v=xrLNDgrIw3U

    (Spoiler: The video discusses the carbon build-up due in direct-injection engines that did not have additional port injection, known as “dual injection”. It does not discuss the build-up because of high RPM at low manifold pressure. It does discuss the catch can.)

  • avatar
    Rick

    I have a 2017 Fit Ace of Base with a manual transmission. I love the car and it does remind me of my old ‘92’ Civic SI that I had for almost 14 years.

    I have noticed the car does run better if I get it fully warmed up so I usually ‘combine’ the routine trips into one task to get the car up to temp.

    What also seems to help is getting the car up to 65-70 or so in third for maybe ten minutes on the freeway every now and then. Even at that, the car’s MPG indicator shows almost 45 MPG on level sections. So far, the car has been great and I have had no problems.

    BTW, I have done this with all my cars in the past including the above mentioned 92 Civic SI as well as my 2007 Civic SI and and old Z/28. This really isn’t anything new. With total respect to the sensitivity to the readers, we used to call it giving the car an “Italian tune up”.

    No idea what to do if the Fit is a CVT.

  • avatar
    DeadWeight

    And another formerly rock-solid, reliable Japanese automaker does stupid $hit adopting turbochargers, CVT trans, obviously unproven, not-nearly-tested-enough direct cylinder fuel injection, and a bunch of other idiotic things, and gets burned (and will continue to get burned) by it.

    There was a time, and it lasted for at least 22 years, that a Honda, any Honda, with the exception of a very weak glass transmission for a spate as the exception that proved the rule, was a dead ringer for reliability and durability (you could run them for 230,000 miles plus with even minimum, basic maintenance, with no worries, and hand ’em off to others).

    Those days are, very unfortunately, over.

    Honda will be missed (Acura is largely dead, but for some other reasons as well).

  • avatar
    PrincipalDan

    I was watching some YouTube reviews and “Savage Geese” was talking about how PVC being vented into the combustion chamber was making the DI carbon build up problem worse. They were recommending the installation of an oil catch can if you were serious about keeping a DI vehicle for the long haul.

    Is that even possible with modern engine management systems?

    • 0 avatar
      Kenn

      It seems that many owners are adding catch cans to their PCV systems. Looking at the specs for the latest generation GM 3.6 liter V6 – the “LGX” – I noticed they’ve now added (without fanfare) an oil separator to their fuel system. That sounds promising.

      • 0 avatar
        golden2husky

        Some 6.2 liter engines have also added a “catch can” that drains into the crankcase. Plenty of high quality kits to retrofit your car if you want to. I considered it but heard about the cases of engine warranty claims being denied. So far, no issues – at all.

    • 0 avatar
      lon888

      I’ve had to have the intake valves cleaned on 2012 GTI twice already. I installed an ECS catch can system and can only hope its doing its job of keeping oily air off the intake valves. The last valve clean I did myself and its a messy job…

    • 0 avatar
      JimZ

      yes, that is a large part of the problem. the blow-by of combustion gases past the rings (yes, even in a brand new, tight engine there is blow-by) generates an oil mist in the crankcase, which is sucked into the intake by the PCV system. In an engine with port fuel injection, the inlet ports and valves are being sprayed with (detergent-carrying) liquid gasoline which continually washes away any film of oil sucked in via the PCV. Since DI injects fuel directly into the chamber, that oil mist just builds up and bakes on to the valves and port walls. The best you can do to prevent or at least slow it is to have a good separator system or external catch can.

      FWIW, I’ve looked at the separator assembly built into the valve cover(s) on Ford Ecoboost engines and they’re pretty complex, with lots of baffle/trap features to try to “condense” the oil mist out of the flow before it gets sucked into the intake manifold.

  • avatar
    slavuta

    “From day one I noticed…”

    Surely, what you’ve noticed on day 1 has nothing to do with what you have at 57K. Or, it may be related but nevertheless it wan’t there back then.

    Interesting question: have you pumped Tier-1 gasoline regularly?

    • 0 avatar
      kcflyer

      Good question. Having never heard the term Tier 1 gas before today I did some quick research. I have been using primarily Noco brand gas since moving to western New York 9 years ago. Noco is not listed on the few tier 1 list I have seen so far. Time for a change. Not sure if the Noco gas is good or bad but trying something else seems a reasonable step. I am also researching catch cans. There the picture is far from clear. Some say they are great while others say not so fast and urge caution for several reasons.

      • 0 avatar
        thornmark

        When I got my 2013 Honda that was in the car manual – USE TOP TiER gas.

        I have only used Top Tier, Costco Top Tier.

        I have searched around the internet and have never come up w/ another instance such as yours.

        “DI may not spray the back of intake valves but Top Tier gasoline has other additives that help keep deposits from “sticking” to your valves. Combined with an oil catch can to prevent fuel/oil vapor from being recirculated, it’s your best bet to reduce carbon buildup. “

        • 0 avatar
          ajla

          Diva engine in low-price a subcompact communter that requires ‘top-tier’ fuel and and a catch can. Not impressed by the Big H here.

          But VW is also bad, so it’s alright.

        • 0 avatar
          30-mile fetch

          “I have searched around the internet and have never come up w/ another instance such as yours.”

          You apparently didn’t search very hard before riding in like the white knight to save the damsel in distress and insult the owner, Normmark. This is from a single thread on a single forum and took two minutes to find:

          https://www.fitfreak.net/forums/3rd-generation-2015/87155-possible-direct-injection-issues-2.html#post1379869

          https://www.fitfreak.net/forums/3rd-generation-2015/87155-possible-direct-injection-issues-3.html#post1381846

          https://www.fitfreak.net/forums/3rd-generation-2015/87155-possible-direct-injection-issues-3.html#post1381854

          https://www.fitfreak.net/forums/3rd-generation-2015/87155-possible-direct-injection-issues-3.html#post1381853

          Sometimes our favorite brands aren’t perfect.

      • 0 avatar
        slavuta

        All gas comes from same barrel with minimum required agents in it. Then a Tier-1company adds something to it and it becomes tier-1 gas. The test was performed and proven that Tier-1 cleans the engine while non-tier-1 dirties it. Test engine however wasn’t DI engine.

  • avatar
    slavuta

    Exactly. Could be eventually related but “day 1” has nothing to do with it

  • avatar
    Arthur Dailey

    So my Sonata does benefit from the occasional ‘Italian tune-up’ on the highway, assisted by the fact that as a MT, it is more satisfying for me to redline it.

    Also I use only Tier 1 gas, as per the manufacturer’s recommendation.

    I will also per the comments purchase some Seafoam this weekend and add it to the gas tank.

    Has anyone had any bad experience adding Seafoam to the tank, and at what ‘ratio’ should I mix it?

    • 0 avatar
      JimZ

      “Has anyone had any bad experience adding Seafoam to the tank, and at what ‘ratio’ should I mix it?”

      0:1. it’s useless, don’t waste your money. it’s just mineral spirits, isopropyl alcohol, and a light (pale) oil. a top tier gasoline has more than enough detergents to keep things clean.

      those idiots on YouTube go on and on about “look at all that smoke the SeaFoam is burning off!” without realizing it’s the oil in the Seafoam causing the smoke.

      I never cease to be amazed at the random crap people will dump into their engine, transmission, and/or gas tank. Modern oils and fuels are pretty highly engineered fluids, yet your average numpty somehow believes he knows that they’re substandard and gets suckered in by whatever flowery claims are on the additive bottle.

    • 0 avatar
      Scoutdude

      If you want additional cleaners in the fuel Seafoam isn’t really that effective. Chevron’s Techron is one that will help out as it is an actual engineered product, not something someone whipped up in their garage many decades ago.

      However the down the carb method of using Seafoam will clean internal engine parts, but not any better than plain old water, rubbing alcohol or a mix of the two.

    • 0 avatar

      Our own Bozi says the only additives which do anything have PEA in them (Seafoam doesn’t).

    • 0 avatar
      Lie2me

      Arthur, I use one can per tank (15 gallons) you’ll notice an improvement right away, been using it all my adult life and haven’t had any negative effects

  • avatar
    BrentinWA

    If this were happening with a Chevy or a Ford, people on here would be dog piling on the owner telling him what a POS his car is…. but since this is on a Honda, this is just a “maintenance” issue. SMH

    • 0 avatar
      VW4motion

      +1

    • 0 avatar
      30-mile fetch

      No one here is defending this as simple maintenance just because it’s a Honda. There will, however, likely be a noticeable absence of a certain few big time Honda fans on this thread.

      Considering how many new cars are DI-only, not many people will be able to crow about it one way or the other.

      • 0 avatar
        PrincipalDan

        I’m very interested in this thread just because almost every new gasoline engine is DI. A select few (like Toyota) have gone to a “port/DI” setup because of this issue, but it seems that for many automakers that’s just too costly or complex of a solution.

        • 0 avatar
          White Shadow

          Not all DI engines have carbon problems. Toyota’s method of adding a port injector is a good solution, but there are already plenty of pure DI engines that don’t have carbon issues.

          • 0 avatar
            JimZ

            ALL pure DI engines will have at least *some* buildup/deposits on the valves. even if the separator/traps make the PCV stream squeaky clean, there’s still the oil which works its way down to lubricate the valve guides. The difference between various manufacturers’ DI engines is the degree to which deposits collect.

          • 0 avatar
            White Shadow

            “ALL pure DI engines will have at least *some* buildup/deposits on the valves.”

            Not sure if you’ve ever pulled apart an engine, but somehow I doubt it. ALL engines will have some build up of carbon deposits on the valves DI or not. That’s a fact. Get some mileage on them and it’s a lock.

      • 0 avatar
        Art Vandelay

        Im at 60k on a gen 1 Ford 2.7 with DI only and have had zero issues with it. Supposedly they do something with the Cam timing to get some fuel on the valves, but I do nothing special outside of changing my oil with good synthetic regularly. Still no problems though.

    • 0 avatar
      thornmark

      Because it’s not a Honda problem – VW and others had a huge problem but this is an anomaly from someone who did not read their manual.

      The manual for Earth Dreams says to use Top Tier. Search the internet and you’ll find this problem as rare a hens teeth.

      “So how do Top Tier fuels like Chevron and Texaco with Techron, Shell’s Nitrogen-Enriched, and BP’s Invigorate work? Each employs trade secret organic chemistry (Chevron admits theirs involves a polyether amine. Others often employ polybutene amines, if that helps), but by and large the molecules include a “hydrocarbon tail” (that keeps the detergent soluble in fuel) attached to a head that includes a functional group containing nitrogen. When enough of these nitrogens attach to a deposit, it comes off. Then the nitrogens can attach to the clean surface and prevent new deposits from forming.”

      • 0 avatar
        JimZ

        “Top Tier” or not is irrelevant in this case as no gasoline ever touches the back (port) side of the valves. it can’t clean something it doesn’t come into contact with.

        • 0 avatar
          Scoutdude

          No where in the article does it say that build up on valves was part of the problem. It was the injector itself that was one of the problems and the fuel definitely comes in contact with them. The other time there was supposedly excessive carbon in the cylinder.

    • 0 avatar
      slavuta

      BrentinWA, I’ve been dog piling on Honda for years now. I said and will double, Honda became typical broad-consumption product that no longer has neither charm nor reliability.

  • avatar
    brettc

    This is why I bought a used oddball hybrid that was sold and registered in a CARB state to get the extended hybrid warranty.

    No turbo, no DI, just a CVT paired to a hybrid system that’s warrantied to 150K/10 years. As Deadweight said, Honda is no longer a shining star of dependability and low maintenance costs.

    After owning a TDI with a DSG and owning older TDIs that needed periodic intake cleaning, I have no interest in dealing with cars that are engineered to suck due to more stringent emissions regulations. I like clean air, but some of the things that are done to comply with emissions seem to defeat the purpose.

    Jury is still out for me on VW’s EA888 TSI. So far no carbon problems, but it only has 40000 miles. Time will tell.

    • 0 avatar
      White Shadow

      VWEA888 is very common in VW & Audi vehicles. Both the 2nd and 3rd generations of this engine are basically free of carbon issues. Apparently, turbocharging and DI can play nice together.

      • 0 avatar
        30-mile fetch

        “Both the 2nd and 3rd generations of this engine are basically free of carbon issues”

        US or European market EA888s? VW left out the dual injection from US market engines.

        • 0 avatar
          White Shadow

          Correct. And carbon issues are virtually non-existent. The forums tell the story. Easy to determine which engines have carbon problems and which don’t. BTW, only gen 3 versions have secondary port injection, and then only in non-North American vehicles. Even so, no discernable difference in this engines. And gen 2 engines don’t have port injection at all, yet they still don’t suffer from carbon issues.

  • avatar
    macnab

    Chevron’s Techron is an old, well regarded cleaning additive but I too can’t see how it gets to the cold side of the valves. I’ve been wary of DI from the start. It’s part of the reason I bought a Chev SS with a port injected, pushrod, small block V8. Can somebody tell me if the injection pump in DI cars is reliable? Diesel pumps are pricey and the gas versions should be similar.

    • 0 avatar
      JimZ

      the HPFP for the Ford 2.0 DI is about $190. gas DI only runs at about 2,000 psi. the diesel ones (e.g. Transit 3.2) cost about twice that. They’re fairly simple units, only there to pressurize the fuel rail. They’re not as costly as the distributor or inline injection pumps of the old days.

    • 0 avatar
      MBella

      The only way to get it on the backs of the valves is to allow it to suck into the intake somehow.

      • 0 avatar
        JimZ

        delayed intake valve closing (like on the pseudo-Atkinson cycle timing used on hybrids) will allow that, but the fuel is mostly evaporated at that point anyway.

  • avatar
    kcflyer

    You are right of course that fuel additives won’t help in areas they don’t travel. Although maybe the additives that wind up in the “blow by” junk that is getting dumped back into the intake valves will have some effect. What they will do hopefully is keep the pricey injectors clean. If I had to pay for them without help from Honda of America I would have been out $1200, and that was a “discounted” rate from the dealer where I purchased the car. Only one was showing clogged but they come in a set that includes all four. It’s all rather depressing. I bought this car to be relatively cheap, reliable transportation as my commuter. Now I know that was a mistake and that I doubled down on that mistake with the 17 Civic before this problem was made clear.

    • 0 avatar
      Scoutdude

      I would bet that they are available individually in the aftermarket and if they are not now they will be in the future.

      Top tier gas my prevent future problems with the injectors. Don’t listen to most of the commenters here that claim that won’t help. It is true that gas won’t clean the back of the intake valves in a DI engine but the problems you have had thus far are not related to carbon on the intake valves they have mainly been in-cylinder issues.

      Unfortunately it sounds like even with the goodwill you’ve kind of got the shaft from the Honda dealer since $217 is pretty steep for cleaning a throttle body.

      Also there should not have been a need to pull the head to see if the pistons have excessive carbon build up. There are affordable inspection cameras that will fit down a spark plug hole with incredible resolution available today.

      The old method of removing in cylinder carbon was steam cleaning. Of course this is back when carb mean carburetor, not carbohydrate. Step one was to take it out and get it fully warmed up with a good old Italian tune-up. Then grab an empty Coke bottle fill it with water and remove the air cleaner. Then hold the throttle open so the engine is running at 2500-3500 rpm and dribble the water down each primary barrel. Not so easy with a modern car but it can still be done.

      • 0 avatar
        kcflyer

        I was told they pulled the head at the bequest of the Honda of America tech rep. They did this to clean up the piston heads and valves which were all nasty. This process has kept the check engine light off for the last 1000 miles but the hesitation issue persist even during summer days when the engine is cold. So now I’m stuck with two relatively new Honda’s. I will switch fuel suppliers for both. Try to find full synthetic motor oil in the correct viscosity. I may put an aftermarket catch can on the Fit since it’s now out of warranty but I if I do that mod to the Civic I would likely void it’s warranty in an effort to avoid the carbon problem.

        • 0 avatar
          scottcom36

          Now you’re going to try to find full synthetic oil in the correct viscosity? Have you been using the correct oil?

          • 0 avatar
            kcflyer

            I have always used the manufacturer recommended viscosity and ALWAYS changed the oil and filter every 3,000 miles. The oil has not been full synthetic. From now on it will be as this my make the oil less likely to wind up in the intake system evidently.

  • avatar
    someoldfool

    Non one mentions what we who live in the Corn Belt deal with, 10% ethanol in the gasoline. There is one station in our area, population 130,000, that sells alcohol free gas. Our Acuras run better, the old 2010 runs a lot better on the 100% gasoline. Especially in the winter. Politics here come down strongly for 90-10 gasoline, and E-85 of course.

    • 0 avatar
      slavuta

      Wow – you’ve discovered America! A corn-belt! I have not seen anything that sells 100% gas anywhere from DC to NH.

      • 0 avatar
        JimZ

        ethanol-free is easy to find if you live near water; marinas sell it. too many old outboards still in use which have materials in the carbs incompatible with eth.

      • 0 avatar
        rocketrodeo

        slavuta–there are thousands of stations that sell ethanol free gasoline, pretty much everywhere. Easier to find in some states than others in normal octane ranges. pure-gas.org is your friend.

        Pretty much all cars made in the past 20 years can use ethanol-laced gas with few problems if it doesn’t sit in the tank long. Carbureted vehicles and many motorcycles, not so much. Worth seeking out ethanol-free stations in those cases.

        • 0 avatar
          Arthur Dailey

          Where can we find ethanol free gasoline in Ontario? It seems that all of the large retailers PetroCan/Suncor, Shell and Esso are the Tier 1’s and Husky and Ultramar (yes there is not much competition in Canadian gas retailing), sell fuel with up to 15% ethanol.

          • 0 avatar
            Lie2me

            According to pure-gas.org you can get ethanol free gas at the following in Canada

            All Canada: Shell V-Power 91, Canadian Tire 91
            Atlantic Canada: Irving Fuels premium
            Western Canada: CO-OP premium
            Newfoundland, Nova Scotia, PEI: all premium? Please confirm with evidence!
            British Columbia: Chevron 94
            Ontario: Costco 91; Canadian Tire 91; Ultramar 91

        • 0 avatar
          slavuta

          rocketrodeo,

          oh! – Great. I have to drive into airport to get gas. Ok, they are there but they are not here. What can I say, this is like Russian made AK47. I know they exist but you can call 100 gun shops and non have them. Super!

    • 0 avatar
      Johnster

      This is pretty much an issue everywhere in the U.S., not just the corn belt. My old Honda Civic sure runs better with alcohol-free gas and it gets better gas mileage, too.

    • 0 avatar
      Lie2me

      I live in the corn belt, but also where there’s a lot of boating, 100% gas is pretty easy to find and is all I’ll put in my car

    • 0 avatar
      Scoutdude

      You don’t have to live in the Corn Belt to deal with E10. Many states have E10 mandates and that can have effects outside of the state’s boarders due to the way the distribution system works. I live in WA state but thanks to OR’s E10 mandate 100% gasoline is very difficult to find. The two state’s petroleum industries are linked by pipeline and that has made it easier and cheaper for them standardize producing and introducing into the pipeline only sub-octane gas intended to be blended into E10 to have the proper octane.

      So around here the way to get E0 is to go to a Cenex where you get fuel produced in the Cenex refinery in MT and delivered by truck.

  • avatar
    kcflyer

    Way out side of the traditional corn belt here in western NY. They still grow plenty of corn though and only a handful of stations carry ethanol free gas. I seek them out for my boat, motorcycle and power washer gas. It’s about 35 cents a gallon higher than basic unleaded with 10 percent corn juice.

    • 0 avatar
      Fordson

      In Lewiston here – there are a million places to buy ethanol-free gas – the Tops station that’s 600 yards from my house, Smokin’s Joe’s and Jay’s Place on the reservation, plenty of others. Think you can get it at Delta Sonic, too.

      Those places are all within 10 miles of my house…and probably yours, too.

      I don’t think you have a direct-injection issue, personally. Not if it was happening from new.

      • 0 avatar
        kcflyer

        Didn’t know about the Tops having it. The Tops in Lockport doesn’t’. I have sworn off Smoking Joes. The last two times I used their pumps my debit card got compromised within two days. Maybe a coincidence but I think not.

  • avatar
    ixim

    Anecdote here. Owned three DI GM 2.4L Equinoxes; a 2013,a 2016 and a 2017. The ’13 was run on cheap regular and developed signs of carbon buildup – pinging, poor response and lower mpg. The ’16 was treated periodically with Techron per the instructions and had fewer but still noticeable symptoms. The ’17 has been run on Tier 1 gas from Day 1; it just gets smoother, quieter and more responsive every fillup. Better MPG, too. Over 75,000 combined miles, I’ve never gone for the dealer’s $400 TB cleanup and the idea of me having to install a catchment jar is unacceptable. OP needs to find out why the problem existed from Day 1, though.

  • avatar
    johnny ro

    I had an FAA Airframe and Powerplant mechanic license back in the ’80s.

    The power plant manual had a procedure for pouring a small (pint maybe) amount of distilled water through the carburetor while the engine was running. Rev it up while pour.

    Seafoam has this procedure using the seafoam and a rubber tube, you find the plug in manifold to use.

    The FAA approved the water pour procedure for piston engines in aircraft. The water would steam up and the carbon would loosen and go out the exhaust. Yes the steam would hit backside of those intake valves.

    I have tried it with a Mk1 Jetta, 30 years ago, but no idea if it helped anything.

    I wonder how Honda would feel about this procedure on their DI motor. I am quite sure they are aware of it.

    Lets see the B&B try it and report back, or find youtube post?

    I agree the carbon did not make the stumble on day 1 for the OP. Seems pretty obvious.

    I remember Audi dealer service staff dumbly and not innocently telling me to use top tier and that they cannot figure out why my knock sensor keeps coming on. My bet is they torqued the replacement wrong. Goons.

  • avatar
    Lightspeed

    These things are getting too GD complicated. My newest car will be a 2005, no GDI, no internet, no push-button start.

  • avatar
    f1tifoso

    Carbon buildup is caused by the carbon in fuel backwashing – it is a design flaw they didn’t foresee (starting with AUDI’s DI engines)
    >port injection was largely self cleaning (except cheap gas left deposits) while direct injection has caused this problemever since (Audi recommendation to keep it clean? Take it to redline once a week…)
    a few newer systems have solved the problem with flow analysis while others now have both port and direct paired fuel injectors which prevents the problem as well (they use the DI for efficiency and port for power, allowing smaller DI injectors – of course twice the injectors = $$…)
    To fix: You can buy DI cleaner spray for about 3-4x the price of plain carb cleaner, and it is about 20x more concentrated (have tested both on the gunk and it is very effective) and spray off the polluted intake etc. I don’t believe the pistons carbon are a DI problem, that’s a tier 2 fuel problem.

  • avatar
    gearhead77

    Just run it hard once in a while. I’m fairly sure a trip to WOT once in awhile isn’t killing anything, including mileage. .1 mpg to keep the carbon away and large repairs? A tank of premium Tier 1 fuel every once in awhile? Cheap to me

Read all comments

Back to TopLeave a Reply

You must be logged in to post a comment.

Recent Comments

  • spookiness: I like the CX-30 a lot. But a lightly-used, loaded 17′-18′ CX-5 or Mazda3 hatch’s seem...
  • thecastle: They say the higher the hood the closer to god. Besides the engines havent gotten physically larger and...
  • bryanska: Dodge makes good-enough cars with plenty of features, and sells them cheap. I rented a Grand Caravan last...
  • Art Vandelay: @MCS I’ll simply throw out the “why do you need…” Argument that truck owners...
  • Art Vandelay: I do like the way EVs drive, but in fairness I have quite a few friends that did buy them specifically...

New Car Research

Get a Free Dealer Quote

Who We Are

  • Matthew Guy
  • Timothy Cain
  • Adam Tonge
  • Bozi Tatarevic
  • Chris Tonn
  • Corey Lewis
  • Mark Baruth
  • Ronnie Schreiber