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

  1. #21
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    Quote Originally Posted by old mechanic View Post
    Lets ASS-UME their diagnosis is correct. With an engine running perfectly, the only rational explanation of which I know is the contamination accumulated on the intake valve stems and the engine cooled overnight that same accumulation cooled and congealed into a kind of plastic type of material that would not allow the valves to close completely when you tried to restart the car next morning.

    This makes sense, but there would be one piece of evidence. The engine would crank over faster than normal, just like an engine will when you remove the spark plugs and there is no compression.

    If the repair shop is familiar with these symptoms then there must be a lot of bad gas sold at stations near that shop. Never heard of it happening in the US, from personal experience, with a single exception posted previously.

    Based on the belief that you're description of the problem is perfectly accurate.

    I know of no other possible cause. That's after over 30 years working on cars, with a single example of virtually identical symptoms.

    How could the engine run perfectly then loose compression on every cylinder?

    I'll follow this thread carefully, maybe learn something new.

    UNDER NO CIRCUMSTANCES DRIVE THE CAR ON THE "FUEL" IN THE TANK OR YOU RISK HAVING THE EXACT SAME THING HAPPEN AGAIN AND I DOUBT SERIOUSLY WORK WOULD BE DONE AGAIN UNDER WARRANTY.

    regards
    mech
    Any chances someone likes OP and dumped a cup of sugar into tank?

    Here is a quote on TopTier gas from GM engineer:
    https://en.wikipedia.org/wiki/Top_Ti...rgent_Gasoline
    While General Motors' fuels engineer Andrew Buczynsky states that no one has identified the exact molecule in gasoline that causes engine buildup, he asserts that consistent use of Top Tier Detergent Gasoline will keep engines cleaner.[4] Engine gunk typically builds up in fuel injectors and intake valves, causing reduced fuel efficiency, acceleration, and power, as well as increasing emissions, rough idling, tendency to stall, and increased motor repairs
    TT requirements:
    In order to be certified as Top Tier, a gasoline must pass a series of performance tests that demonstrate specified levels of: 1) deposit control on intake valves; 2) deposit control on fuel injectors; 3) deposit control on combustion chambers; 4) prevention of intake-valve sticking
    I suspect the reason we don't see it in US this is unlikely due to %10 alcohol mandate.


        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)


  2. #22
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    Quote Originally Posted by BRagland View Post
    I hate to burst your bubble, but I highly doubt the software has anything to do with this problem. The EGR system is not as dirty as people make it out to be. Ironically, the highest contaminate in combustion gasses is water (other than CO2). Yes, there is some soot in those EGR gasses, but it's very-minimal in such a small engine, and the spray pattern from the fuel injectors would take care of it without a hitch.

    If the fuel is dirty, than perhaps the EGR gasses would be too (sticky substance in, sticky goo out). But that cannot be remedy by software. The only remedy, would be to put clean fuel in the tank.
    Answer:

    1) This car has no EGR.

    2) Old Mechanic's assumption the fuel being no good sounds logical and makes sense, but:
    a):I filled up last at a well-known Shell brand station in Luxemburg a few hundred km away.
    b) The local company using a half a dozen similar 3A90 Space Star/Mirages has suffered the same problem with each vehicle at least once, and they had much less milage at each occurence than my long-distance driven car, and I don't buy from "their" same gas station. After filling up last time, I immediately drove a few hundred km, so nobody could have done anything to the tank.

    3) I don't really believe it is a software problem either, but I have to give them a chance to fix it. Then if they claim to have fixed it, I would have to wait to see how long their fix lasts...
    Last edited by foama; 01-06-2016 at 06:09 PM.

  3. #23
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    Quote Originally Posted by foama View Post
    2) Old Mechanic's assumption the fuel were no good sounds logical and makes sense, but: A) I filled up at a well-known brand station a few hundred km away. B) The local company using a half a dozen similar 3A90 Space Star/Mirages has suffered the same problem with each vehicle at least once.
    In US we have EPA fuel requirements and also industry voluntary TopTier certification. TT requires x3 times more cleaning detergents than EPA. Some of the brand names are not on the TopTier list. If situation is similar in Germany, then buying from brand name would not mean much too.

    Shell is on the list in US and Canada:
    http://www.toptiergas.com/retailers/

    EDIT:
    and the problem isn't b/c of one bad fill up, it takes long time for deposits to build up.

    Since this doesn't happen to other cars you had driven, I'd go with oil issues, such as foaming/PCV and/or valve seals. If it is problem with PCV there should be oil in PCV hose.
    Last edited by cyclopathic; 01-06-2016 at 06:22 PM.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)


  4. #24
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    Junk yard gas will always be an issue until it is collected while fresh and put in fuel tanks to be consumed. No better use or disposal process should exist. If in doubt, test it cheaply, and separate the bad lots for different burning scenarios or other disposal processes. The financial incentive is substantial when the collector and distributor are the same ownership. Take it out of this car, pour it in my tanks for public sale, FOR THE SECOND TIME.

    regards
    mech
    Last edited by deleted user; 01-07-2016 at 12:52 AM.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage de 1.2 manual: 55.7 mpg (US) ... 23.7 km/L ... 4.2 L/100 km ... 66.9 mpg (Imp)


  5. #25
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    Quote Originally Posted by foama View Post
    Answer:

    1) This car has no EGR.

    2) Old Mechanic's assumption the fuel being no good sounds logical and makes sense, but:
    a):I filled up last at a well-known Shell brand station in Luxemburg a few hundred km away.
    b) The local company using a half a dozen similar 3A90 Space Star/Mirages has suffered the same problem with each vehicle at least once, and they had much less milage at each occurence than my long-distance driven car, and I don't buy from "their" same gas station. After filling up last time, I immediately drove a few hundred km, so nobody could have done anything to the tank.

    3) I don't really believe it is a software problem either, but I have to give them a chance to fix it. Then if they claim to have fixed it, I would have to wait to see how long their fix lasts...
    Thanks for the reply.

    There is a common problem in the US where the dealers regularly put 4-5 quarts of oil into the engines, when it requires much less. This could be causing excess aeration / foaming which could be either going through the now over-saturated PCV valve, or through some kind of a seal leak due to the oil overfill (or just bad seals from the start) or even both. That excess oil could easily causes carbon build-up problems.

    This could have been the cause for that fleet, maybe you as well, but I'm not sure if you changed your own oil.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 automatic: 51.7 mpg (US) ... 22.0 km/L ... 4.6 L/100 km ... 62.0 mpg (Imp)


  6. The Following User Says Thank You to BRagland For This Useful Post:

    cyclopathic (01-06-2016)

  7. #26
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    It sounds like EGR is being confused with PCV in this discussion.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.0 mpg (US) ... 20.8 km/L ... 4.8 L/100 km ... 58.8 mpg (Imp)


  8. #27
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    Top Tier Gasoline: Why?

    Found here.
    Quote Originally Posted by TopTierGas.com
    Why TOP TIER

    The intention of the TOP TIER Detergent Gasoline standards is to create a winning situation for gasoline retailers, auto manufacturers and drivers. Currently, many gasoline retailers provide fuels with lower-quality additive packages that can build up deposits on fuel injectors and on intake valves. Others can build up deposits in combustion chambers and may lead to intake valve sticking. These lower levels of additives can have negative impacts on engine performance and vehicle responsiveness.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.0 mpg (US) ... 20.8 km/L ... 4.8 L/100 km ... 58.8 mpg (Imp)


  9. #28
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    Quote Originally Posted by Eggman View Post
    It sounds like EGR is being confused with PCV in this discussion.
    I don't think so. Both can cause biuild up though.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)


  10. #29
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    Quote Originally Posted by cyclopathic View Post
    I don't think so. Both can cause build up though.
    Which do you think would be more likely to cause a buildup on a intake valve - exhaust gas recirculation, or positive crankcase ventilation? I would guess PCV over EGR.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.0 mpg (US) ... 20.8 km/L ... 4.8 L/100 km ... 58.8 mpg (Imp)


  11. #30
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    Quote Originally Posted by Eggman View Post
    Which do you think would be more likely to cause a buildup on a intake valve - exhaust gas recirculation, or positive crankcase ventilation? I would guess PCV over EGR.
    Hot exhaust gases provide temperature and at start up carbon particular matter which can speed things up.

    IMHO EGR or PCV it is speculation someone needs to check both.

    BTW if build up is due to egr/running rich ECU map update could help.


        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)


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