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Thread: Any mechanically inclined types here?

  1. #1
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    Any mechanically inclined types here?

    Hi all,

    I'm not talking "I know how to change the oil" types, you'll need to have a little more experience to help out here.

    So, the little car decided to misbehave last night as we went for a drive, being seriously down on power. The car in question is a Mitsubishi i (egg on wheels), and it seemed like the turbo was not spooling up at all. Because of that, it seemed like it lost half of it's meagre 60 odd horsepower, which when you start with so little, losing half is a big hit. Otherwise, it started and ran just fine just lacking go beyond 3K rpm without giving it a real hard time.

    Just now checked as much mechanically as I could and noted that the wastegate and actuator are all moving like they should, and the wastegate actuates like it should with about 7-10psi (about, because my compressor isn't exactly a precision instrument) and fully opening at maybe 12psi or so. No damaged pipes or tubes anywhere I could see. Pulled off the inlet to the turbo compressor side and there's a tiny bit of play in the bearings (150K km, expected) but seems to be ok and the wheel turns with compressed air blown onto it, so checked all the turbo bits and they all seem to be working.

    Got to the blow off valve, and ran a little compressed air on both sides, and it seemed to be a little 'clunky' but operating with compressed air to it. Completely stock standard valve, vents to the pre-turbo inlet. As I'd run out of mechanical items to check for operation, put it all back together and went for a drive, and maybe something has been wrong for quite a while because it seems to have more power than it ever did. Perhaps (but hard to be sure) the valve was stuck closed for a moment as it seemed to surge during a gear change (it's an auto) but stopped that and operated as normal from then on out.

    So, the problem seems to be that blow off valve being stuck open and not letting boost build up. Would that be a plausible explanation for this kind of power loss? Seems to be it could be, but I'm working on a basis of one case, and one case only. And can I reasonably expect to be able to clean the stock valve so it works like it should? If so, any tips on cleaning it?

    I think I've worked out what was wrong and solved it for the short term, but just kinda looking for confirmation.

    And I do not suggest doing automotive maintenance while living in Japan. A lot harder than it should be...

    Thanks, I hope.

    Stu.

  2. #2
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    i would bet it is the blow off just dumping its guts everywhere

    cost of diagnosis: 1 case of beer :P
    steve.c, merexy and Schtoo like this.
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  3. #3
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    A BOV can do that mate. Make sure there's no grit in there and clean and lubricate it so it slides smoothly. Also make sure to check if there's a vacuum line going to the BOV. It could be leaking and causing it to stay open. Check the spring too.
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  4. #4
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    However a loss of power would probably more be likely due to the wastegate on the turbo being open due to a vacuum line being faulty or something else. If the wastegate is open it won't allow the turbo to spool up.
    iamtezr likes this.

  5. #5
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    Any mechanically inclined types here?

    Stu,

    There could be various things that can cause power loss. Hard to say but how certain are you thinking the culprit is the BOV?

    I'm guessing it's a stock BOV so I'll be a plumb back. Harder to test compared to a vent one. I guess you removed it and it's position was wide open rather than closed.

    You can always buy an after market one to test.
    Even if you did the soapy water leak test and if there was a leak, it will still spool and release.

    Hope it's just the BOV as it's much "cheaper" replaceable part compares to others.

    AFM sensors can cause power loss.
    Also faulty fuel pump can cause power loss too.


    ETA: I don't think you need to clean the BOV at all. I've never done so and don't think anyone I know has. I've got a feeling it may be your AFM sensor that could be dirty and not giving enough airflow through causing the power loss.

    That's probably the first thing I'll check and clean.
    Tez.
    Last edited by iamtezr; 04-09-17 at 08:37 PM.
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  6. #6
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    Quote Originally Posted by gurishka View Post
    However a loss of power would probably more be likely due to the wastegate on the turbo being open due to a vacuum line being faulty or something else. If the wastegate is open it won't allow the turbo to spool up.
    This.
    Do a thorough soapy water leak test. The vacuum hose near the turbo will probably be hard and hard to see if it has cracked and leaked. I would replace the vacuum hose if it looks old, hard and dry.
    gurishka likes this.

  7. #7
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    I was going to say MAP/MAF sensor too... or an ECU fault issue coming from a sensor. But if the wastegate is stuck open on the turbo it won't spool up.. (I'm a broken record sorry)

  8. #8
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    Stu,
    If you were closer I would have lent you this baby...


    Also use this to clean your MAF sensor.


  9. #9
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    That's the thing, I've checked it all mechanically and running pressure wherever pressure 'makes it tick' and checked all the lines and no leaks to speak of. Wastegate actuator is working, and as it's now producing boost the actual 'spooling up -> making pressure' seems to be working fine.

    Used to be you could barely hear it spooling up, now it's distinctly noticeable and the only 'problem' part I found was that clunky BOV which I thought should operate a lot smoother than it was. It's just that it's quite small (as is the whole setup) and I didn't think it would flow that much air to drain the intake pressure off all the time without being completely overwhelmed and letting some pressure through. Maybe it was letting some through but being so down on power it was hard to tell.

    Otherwise the engine itself is running fine. No smoke, no hiccups, no dramas of any kind. Fuel and spark and all the rest seem fine, no check engine light and I'll be checking for any codes tomorrow when a proper scanner arrives.

    I'll take it for a trip in an hour or so and see that it's still got it's pep.

    The confusing part was that there was no noise from the turbo like it usually did along with no power. Maybe when it's not under any load (as in dumping all the pressure) it wasn't working very hard and made no noise? Really odd, which is why I'm asking.

    If I didn't stumble across that questionable BOV, soapy water was the next thing to try along with the air compressor supplying the air. I'll pull the BOV on Sunday and give it a birthday anyway, just to make sure it's working as well as it can. A genuine replacement is about $150, which I'm not going to spend on this thing and don't want a whooshy one so might have to try find a used one if this one is the culprit and doesn't come good.

    Not that any of this is important. It's the second car, somewhat disposable and only used for short trips. When it dies, I hope we can snaffle the electric version to replace it, if it'll ever die. 150K km, and the engine itself runs like a Russian tractor. Not sweet, but sounds like it'll never stop running...

    Stu.
    gurishka and iamtezr like this.

  10. #10
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    Quote Originally Posted by iamtezr View Post
    Stu,
    If you were closer I would have lent you this baby...

    I chit you not, that's twice the size of the turbo in it. If you've ever heard of the fabled tiny turbo, the TD02, that's what it's got. Rebuilt turbos are about $430 off Amazon.

    Kinda cool actually if you reveal it in the right way...

    RWD.
    Mid Engine.
    Turbo.
    Variable valve timing and a 7+K redline.

    660cc, limited to 64hp, 4 seats, 5 doors.

    Stu.
    gurishka and iamtezr like this.

 

 
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