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Incipient turbo failure?

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  • #16
    Abbreviated post as CBA rewriting an entire post which has somehow been lost to the ether.

    Car running well - plenty boost and no overboost/limp mode issue. EML took 4 starts to clear though. Why was it on when it wasn't when car shut down after 75 miles of running with jiggered WG actuator (including stop/start before final 50 miles)? No noise - other than (normal) start up whistle.

    When fitting clip - think I saw hairline crack on manifold emanating from WG boss - oh joy...

    Found this >> https://youtu.be/taAF30GaVMk?t=169. Mine nowhere close as bad. But, turbos get that bad and don't wreck engine core?

    Going to check play again (and try and measure) and check for contact.

    May phone main dealer and price manifold and turbo. May need sedation afterwards....

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    • #17
      i do recall mercedes doing turbos on an exchange basis

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      • #18
        This...

        Originally posted by Thrumbleux View Post
        EML took 4 starts to clear though. Why was it on when it wasn't when car shut down after 75 miles of running with jiggered WG actuator (including stop/start before final 50 miles)?.
        ...again today. Why is EML on? It's boosting fine (so not limp mode) and not overboosting (into limp mode). The internet says EML can be sign of turbo failing/failure - but how does the ECU know? Puzzled!!!

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        • #19
          Originally posted by Thrumbleux View Post
          Found this >> https://youtu.be/taAF30GaVMk?t=169. Mine nowhere close as bad. But, turbos get that bad and don't wreck engine core?
          .
          That guy looks like Rasputin.

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          • #20
            You've met Rasputin? Wow!

            Any idea why my EML is lit up like Farage when Trump speaks his name?

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            • #21
              Can only be waste gate setting. Think you need to alter preload perhaps monitor manifold pressure whilst you drive.

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              • #22
                Originally posted by tolsen View Post
                Can only be waste gate setting. Think you need to alter preload perhaps monitor manifold pressure whilst you drive.

                Inclined to agree that that is all it can be, but, boost is coming in right on cue so WG not retarded in closing. And it's not overboosting (I'm aware of how sensitive to overboost having had that issue before (failed cycle valve IIRC - fixed under warranty)) and how easily it goes to limp mode - which it isn't doing. All of which implies the WG can open and close to its full extent.

                EML fails to extinguish on start up - which puts suspicion on its 'hold the WG open, heat the cat' strategy employed for the first 30s or so from cold start (referred to by some as 'autochoke phase'). What signal is the ECU reading to trigger EML? Second Lambda sensor too cold? Boost during initial warm-up phase that should be negated by open WG?
                I think I need to study the working of the actuator's chambers and try to figure if the one responsible for the above has lost a connection or isn't working. (Three chambers in total I think). Pissing rain is not helping!

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                • #23
                  Read fault codes to see what is wrong.

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                  • #24
                    Nearest code reader is at least 50 miles away and until I ascertain the condition of my turbo, I'm loathe to do more miles than I absolutely have to.
                    The EML has to be tied to cold start strategy - so some clue there as to what to investigate re that. Turbo condition I'm waiting for the torrents of rain to subside - whenever that will be.... I can't see how a bit of play in the turbo can illuminate the EML - no matter what the internet says.

                    The two electrical connections that could light up the EML (#2 Lambda and (presumably) and cycle valve (assuming it controls WG during cold start) were both disturbed during actuator replacement. Pretty sure I reconnected them firmly, but perhaps one has jumped.

                    Still paranoid about turbo debris passing through engine core - yet many have had turbos fail and never reported engine damage. Where are they now?....

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                    • #25
                      New turbo (cartridge) ordered as current turbo has radial play visible by eye - but turns smoothly and quietly nonetheless. Hopefully its replacement arrives before a 100+ mile round trip scheduled for next week. If not (probable) then the existing one has to do a bit more before retirement.

                      Couldn't find anything amiss re EML -- all pipes and elec connections as they should be. Lengthening the pipes sure makes working with the TIK a whole lot easier.

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                      • #26
                        Wastegate solenoid might be jiggered.

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                        • #27
                          Originally posted by Buckster View Post
                          Wastegate solenoid might be jiggered.

                          Possible - but as this sprung from replacing the wastegate actuator, I'm still looking at that as the cause.
                          Wastegate actuator will be removed again when turbo (cartridge) is replaced and after that (and more thoroughly examining wastegate arm motion vs actuator motion) if it persists, I'll look there. Replacement turbo due early next week so not long. And, removes the risk of current turbo disintegrating - which, if it occurs, occured to me that it could wreck the compressor housing (which I would then need to source).

                          Once that's all taken care of, car should be good - until manifold cracks start to intrude.... All this (engine rebuilt, turbo replacement) on a car with a mere 76,000 miles under its wheels. Smart - making British Leyland products appear durable.

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                          • #28
                            Originally posted by tolsen View Post

                            Image shows my spare China KKK KP31 copy turbo. Measuring radial play on cylindrical part of compressor wheel nut. Radial play 0.38 mm. Axial play was nil.
                            .
                            New turbo cartridge arrived today. And it, by eye, is wallopping around like the one still in the car. But when I measure with a dial gauge radial play (measured as per Tolsen's) IMG_4193.JPG is 0.32mm and axial play 0.02mm. My conclusion is that my existing turbo is fine and I now have a spare!

                            One slight concern. Presumably the grinding to the nuts is for balancing. The nut on the turbine is quite heavily ground - through to the shaft? To put some numbers on it, I'm measuring 8.8mm across the nut (the peaks, not the flats) where it is uncut and 6.9mm in the ground groove ie, 1.9mm has been ground out. If the 5.8mm 'circle' is the end of the shaft than there's not much meat left. If the shaft is the same diameter as at the compressor end then nothing to worry about, but it doesn't look to be.

                            . Should I be worried?

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                            • Thrumbleux
                              Thrumbleux commented
                              Editing a comment
                              No, no need to worry as it isn't a nut as the wheel and shaft are in one piece.

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