Page 9 of 10 FirstFirst ... 78910 LastLast
Results 81 to 90 of 93

Thread: 3A90 Intake valves stuck open, carbonized, full of gunk and car won't start

  1. #81
    Moderator Eggman's Avatar
    Join Date
    Sep 2015
    Location
    Cleveland, Ohio
    Country
    United States
    Posts
    8,329
    Thanks
    3,667
    Thanked 2,140 Times in 1,620 Posts
    Quote Originally Posted by foama View Post
    Although the car uses practically no oil, I ordered a little catch can that might help condensing some of those combustion byproducts. It will be intalled in the 10mm hose between valve cover and intake manifold. I wonder if it makes any difference...
    Looking forward to seeing how you install your oil catch can.



    Quote Originally Posted by foama View Post
    A chemical engineer explained to me that E10 fuel (10% alcohol) plus acidic greasy combustion products cause exactly that sort of residue. I didn't really understand what he said, but understood it had something to do with chemical reactions, the higher alcohol content of the fuel, and the blow-by reentering the intake.
    Valvoline has this to say about carbon fouling:

    Quote Originally Posted by team.valvoline.com
    The Truth Behind Carbon Buildup
    Dan Carney | Sep 4, 2019

    We all know that gasoline is the fuel that provides power in our cars’ engines. But along the way to the combustion chamber, that gasoline provides the additional benefit of serving as a solvent that cleans the intake port and intake valve.

    At least, it used to on carbureted and port fuel injected engines. But modern, fuel-sipping engines employ direct fuel injection that shoots the gasoline straight into the combustion chamber rather than spraying it into the intake port.

    There are good reasons for doing it this way. Gasoline direct injection lets engine designers account for practically every molecule of gasoline going into the engine so they can extract the most energy and produce the least possible pollution.

    These are worthwhile achievements, but it also means that none of those molecules are touching the intake valves on their way to incineration in the combustion chamber. Intake valves have seals on them that keep oil lubricating where they meet the camshaft or rocker arms that press the valves open from running down their stem and dripping into the intake port.

    However, no matter how good they may be, a tiny bit of oil still makes its way past and runs onto those intake valve stems. Valvoline engineer Michael Warholic reports that Valvoline regularly inspects the insides of engines with a borescope, and what they are finding is disconcerting, “It's likely you'll see a small amount of oil running down the sides of the valve,” he said. Without gasoline washing them clean, that oil can bake onto the valve and accumulate into carbon buildup.

    Naturally, oil isn’t partial to just the intake valves. It also runs down the exhaust valves but in small amounts. The heat of the exhaust gases exiting the combustion chamber burns the exhaust valves clean.

    However, on the cooler intake valve side, carbon can build up so much that it interferes with airflow through the intake port or even enough to prevent the intake valve from sealing properly when it closes.


    Direct injection is a fairly new technology and there are variations among car manufacturers in the design of their versions of these modern engines. According to Warholic, “Some vehicles are more prone to intake valve carbon buildup than others.”

    “These deposits can form quickly, within 20,000 to 25,000 miles and can cause issues related to fuel economy and performance because the intake valve can’t close properly,” he said.

    Also, chunks of those deposits can break off and fall into the cylinder where they can jam the piston rings. This can lead the engine to burn oil that sneaks past these obstructed rings. Because most modern cars use very little oil, drivers are no longer in the habit of regularly checking engine oil levels. Warholic warned that an engine with jammed piston rings could deplete its oil supply before its next oil change, causing engine failure.

    “We want to make people aware of the problem,” he said. “It is not something they should take lightly because it could lead to catastrophic failure.”

    These problems arise even on relatively low-mileage engines whose valve seals are in good working order. It is simply the nature of direct-injection engines that can’t keep intake valves as clean as older port-injected engines once did.

    Some gasoline companies and car manufacturers point to the use of high-quality gasoline with good detergents to help prevent carbon deposits. While gasoline can keep fuel injection systems clean, there is not much it can do about carbon buildup. The gas never touches the intake valves because it gets injected into the combustion chamber downstream of the intake valve.

    “Cleaning injectors, that’s good,” said Warholic of the cleansing gasoline. “But it is nowhere near the intake valve, so it is addressing a problem but not the intake valve problem.”

    What will help with these issues is Vavoline’s Modern Engine Full Synthetic, which is specifically formulated with additives to reduce carbon buildup more than other oils. “It is hot there, so that oil has to be able to withstand oxidation, thermal breakdown, and degradation or that oil can form deposits over time,” Warholic explained.

    That’s exactly what Valvoline Modern Engine does that other high-quality oils, even synthetics, don’t. Valvoline Modern Engine is an oil that is specifically designed to address a problem and take measures to solve, while others remain seemingly fixated on the ineffective notion of cleaning by the use of special fuel. Warholic believes, “Modern Engine is only one designed for this.”

    As carmakers get a better grip on direct injection technology for upcoming models, this problem may diminish in the future. Ford, for example, has gone from direct injection only on its EcoBoost engines to dual systems of both port and direct injection.

    The company says that the dual system provides power, efficiency, and drivability gains. However, it will also have the added benefit of shooting gasoline into the intake ports when the engine is running in port injection mode, which should solve the problem of oil baking onto the valve stems.

    For those of us who have cars that may already have carbon buildup on the intake valves, Valvoline Instant Oil Change locations can inspect to see if that’s the case. If so, they can perform an EasyGDI service to clean those valves and remove any buildup that may have accumulated over time.

    EasyGDI employs a proprietary chemical mixture that the technician runs through the engine to clean the valves. “It is not something you just pour into your gas tank,” said Warholic. But it is a quick and simple service that avoids costly engine teardowns for repairs.

    Switching to Valvoline Modern Engine Full Synthetic can help to prevent recurring problems with carbon buildup in the future.
    I'm not saying that this is what is happening to your engine foama, only that this is Valvoline's take. And of course they hawk their product in the delivery.

    BMW owners have developed a way to use walnut shells to blast away the carbon fouling through the intake manifold port.

    It all makes me appreciate the simplicity of the Mitsubishi design - that is, efficiency without the complication of direct injection and it's shortcomings.


    Last edited by Eggman; 08-02-2020 at 05:06 PM.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.7 mpg (US) ... 21.1 km/L ... 4.7 L/100 km ... 59.7 mpg (Imp)


  2. #82
    Senior Member
    Join Date
    May 2014
    Location
    Country is Europe, state is Germany
    Country
    Germany
    Posts
    907
    Thanks
    105
    Thanked 576 Times in 325 Posts
    Quote Originally Posted by Eggman View Post
    Looking forward to seeing how you install your oil catch can.


    It all makes me appreciate the simplicity of the Mitsubishi design - that is, efficiency without the complication of direct injection and it's shortcomings.
    The little catch can will come from China, delivery around mid September.


    The Valvoline article is interesting, but mainly applies to GDI engines. Our engines have the injectors before the intake valves, no direct injection. Shortly after startup the fuel reaches the valves as a cleansing liquid. Soon after it will be fully evaporated, but during warm-up it will have done some cleaning.

  3. #83
    Moderator Eggman's Avatar
    Join Date
    Sep 2015
    Location
    Cleveland, Ohio
    Country
    United States
    Posts
    8,329
    Thanks
    3,667
    Thanked 2,140 Times in 1,620 Posts
    Quote Originally Posted by foama View Post
    The Valvoline article is interesting, but mainly applies to GDI engines. Our engines have the injectors before the intake valves, no direct injection. Shortly after startup the fuel reaches the valves as a cleansing liquid. Soon after it will be fully evaporated, but during warm-up it will have done some cleaning.
    Of course, and I mention that it doesn't necessarily apply to your situation.

    But it makes me wonder how it happens to your 3A90. Could it really be a single tank of bad gas, or is it possible that it is an accumulation over time that doesn't become a problem until... ? Just speculating.

    I've been following the phenomena of intake valve carbon fouling more lately as I look to replacing an aging car in the driveway. Crazy how carbon fouling is affecting so many engines and interesting how owners and shops are addressing the problem. The BMW crowd has a neat solution with the walnut bead blasting through the intake port. But as we all know this shouldn't be a problem in this day and age of advanced engineering.

    And bummer that it's happening to you.
    Last edited by Eggman; 08-02-2020 at 05:11 PM.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.7 mpg (US) ... 21.1 km/L ... 4.7 L/100 km ... 59.7 mpg (Imp)


  4. #84
    Senior Member
    Join Date
    May 2014
    Location
    Country is Europe, state is Germany
    Country
    Germany
    Posts
    907
    Thanks
    105
    Thanked 576 Times in 325 Posts
    Quote Originally Posted by Eggman View Post
    Of course, and I mention that it doesn't necessarily apply to your situation.

    But it makes me wonder how it happens to your 3A90. Could it really be a single tank of bad gas, or is it possible that it is an accumulation over time that doesn't become a problem until... ? Just speculating.

    I've been following the phenomena of intake valve carbon fouling more lately as I look to replacing an aging car in the driveway. Crazy how carbon fouling is affecting so many engines and interesting how owners and shops are addressing the problem. The BMW crowd has a neat solution with the walnut bead blasting through the intake port. But as we all know this shouldn't be a problem in this day and age of advanced engineering.

    And bummer that it's happening to you.

    In common with the incident years ago, I drove a long distance on the highway, parked the car for a few days, and the valves were stuck with gummy goo.

    As previous post says, only the intake valves had the problem. Regular inspection showed the valves were always nice and clean, just as the top of the pistons. The numbers cast into the piston tops were easily visible. More than a week after the recent second repair, the endoscope shows the inside is perfectly clean again. Strange...


    I was told a mobile nursing company in this town had a little fleet of 3A90, and suffered the same occurence several times. In the end they sold their entire fleet after about two years and bought new Suzuki Celerios from the same dealer.
    Last edited by foama; 08-02-2020 at 06:37 PM.

  5. #85
    Senior Member ahausheer's Avatar
    Join Date
    Dec 2015
    Location
    Mission Viejo
    Country
    United States
    Posts
    330
    Thanks
    165
    Thanked 120 Times in 73 Posts
    Quote Originally Posted by inuvik View Post
    It's the lack of a EGR in the 3A90 1.0 that is a contributing factor for the carbonization along with most likely some bad fuel. This has been a non-issue with the 3A92 1.2. No need for premium, regular grade fuels are just fine. Many members report they drive their Mirages pretty hard all the time with no issues. Just keep driving like you always have been. As far as how fast will a Mirage go? A few members drive 80+ all the time and yes triple digit speeds are possible.
    The 3A92 does not have an EGR valve either. At least not in the US. So I don't think the lack of an EGR is part of the problem.

    And to the previous comment regarding E-10 fuel being part of the problem. I doubt that. 99% of the fuel in California is E-10 and this car is designed for up to E-20. If it was either a lack of EGR valve or E-10 issue the problem should occur more often. I think the mystery remains unsolved.

  6. #86
    Senior Member
    Join Date
    Aug 2017
    Location
    Richland Center
    Country
    United States
    Posts
    3,203
    Thanks
    65
    Thanked 999 Times in 810 Posts
    Quote Originally Posted by ahausheer View Post
    99% of the fuel in California is E-10 and this car is designed for up to E-20.
    Are Mirages sold in California set up differently than other parts of the country? My owner's manual makes no reference to anything more than 10% ethanol gas being acceptable.

    2017 Mirage manual quote -

    "A mixture of up to 10% ethanol (grain alcohol) and 90% unleaded gasoline may be used in your vehicle, provided the octane number is at least as high as that recommended for unleaded gasoline."

    2nd Mirage manual quote -

    "Your vehicle is designed to operate on unleaded gasoline having a minimum octane number of 87 [(MON+RON)/2] or 91 RON."

    I ask, because 87 octane (E-10), 88 octane (E-15), & 91 octane (no ethanol) are very common fuel choices in my area. E-15 is typically 5 cents cheaper than E-10 fuel, but I stick with E-10 (because of the owner's manual recommendation & not wanting to void anything warranty related).

    I highly doubt E-15 would cause issues, but my manual states E-10 is acceptable. E-10 has been around for decades, but E-15 is relatively new (last 2-years or so) here.

  7. #87
    Senior Member
    Join Date
    May 2014
    Location
    Country is Europe, state is Germany
    Country
    Germany
    Posts
    907
    Thanks
    105
    Thanked 576 Times in 325 Posts
    Quote Originally Posted by ahausheer View Post
    The 3A92 does not have an EGR valve either. At least not in the US. So I don't think the lack of an EGR is part of the problem.

    And to the previous comment regarding E-10 fuel being part of the problem. I doubt that. 99% of the fuel in California is E-10 and this car is designed for up to E-20. If it was either a lack of EGR valve or E-10 issue the problem should occur more often. I think the mystery remains unsolved.

    Emission regulations differ from market to market. In Germany for example, the emissions and emission control parts are checked regularly, and if something is not up to par you car loses its approval and can not be moved. If there have been any modifications or alterations to catalyst or other emission controlling parts, it being illegal the car gets impounded instantly and the owner faces criminal charges.

    The fuel in Europe is rated 95 octane, and comes as E5 or E10 with that much ethanol content. E10 is marginally cheaper. There are a few offerings of 98 octane or even higher, but that stuff is extremely more expensive and I have actually never seen anybody buying it. I think of it as a spending bait for those super cool youngsters needing a large Audi, BMW or Mercedes for their over-macho ego as a mental penis extension. Normal folks don't need it. Makes me wonder what Siegmund Freud would have said.

    Here only the 3A90 without AS&G has no EGR, the other 3A90 do have EGR.
    All 3A90 have 11.5:1 compression ratio. All 3A92 in these parts have EGR.

    Only 3A90 without EGR have been noticed to suffer from the problem.
    Last edited by foama; 08-03-2020 at 10:04 AM.

  8. #88
    Cornwallis Fummins's Avatar
    Join Date
    Oct 2016
    Location
    Pyongyang
    Country
    North Korea
    Posts
    4,343
    Thanks
    1,694
    Thanked 1,984 Times in 1,336 Posts
    I thought European fuel was rated in RON not OCTANE. There are many places around here that offer 94 octane/98 RON. 87octane equals 91.1RON

    I donít think octane rating is the problem, maybe poor detergents
    In the fuel? Do you ever use fuel additives/cleaners?

    Speaking of gdi problems, I hear split rims are dangerous!
    My mom says I'm cool

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 37.4 mpg (US) ... 15.9 km/L ... 6.3 L/100 km ... 44.9 mpg (Imp)


  9. #89
    Senior Member
    Join Date
    May 2014
    Location
    Country is Europe, state is Germany
    Country
    Germany
    Posts
    907
    Thanks
    105
    Thanked 576 Times in 325 Posts
    Quote Originally Posted by Fummins View Post
    I thought European fuel was rated in RON not OCTANE. There are many places around here that offer 94 octane/98 RON. 87octane equals 91.1RON

    I don’t think octane rating is the problem, maybe poor detergents
    In the fuel? Do you ever use fuel additives/cleaners?

    Speaking of gdi problems, I hear split rims are dangerous!
    E5 or E10 fuel is actually 95RON = 95ROZ..
    According to ISO 5164 which is also incorporated into DIN as DIN ISO 5164, the fuel in all parts of the world that have accepted the ISO (International Standards Organization) is rated as a "researched octane number" RON or ROZ depending on which language the standard was translated to. A special engine built for this purpose is used at certain exactly defined conditions for testing and rating the octane number. The outcome is actually ROZ or RON but commonly seen as simply "the octane rating". The ISO has been around since 1861, but unfortunately word has obviously not reached all countries yet. North Korea, Liberia and the USA are the last to have their own non-harmonized and mostly incompatible standards.
    To complicate things there is also a MOZ or MON (Motor Octane Number), an SOZ or SON (Street octane number) and a FOZ or FON (Front Octane Number).

    The fences surrounding the world's largest chemical complex is just a few minutes walk away, and I think maybe the fuel tanker had some sort of chemical residue in it before it was filled with fuel for the station. It happened to my 3A90 twice, and several times to a few unfortunate other 3A90 owners too.
    Last edited by foama; 08-03-2020 at 05:17 PM.

  10. #90
    Senior Member ahausheer's Avatar
    Join Date
    Dec 2015
    Location
    Mission Viejo
    Country
    United States
    Posts
    330
    Thanks
    165
    Thanked 120 Times in 73 Posts
    Quote Originally Posted by Mark View Post
    Are Mirages sold in California set up differently than other parts of the country? My owner's manual makes no reference to anything more than 10% ethanol gas being acceptable.
    I can't recommend you do anything against the owners manual, but no, I do not think the California engines are set up differently. I just think for cost, legal, or emissions reasons, Mitsu didn't bother to certify it in America as e20 compatible. The engine specifications thread on this website specifies its E20 compatible as does public marketing material from a few other countries.



Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •