Checking actuator/turbo sticking in place

Discussion in 'VW Mk4 Jetta, Golf, New Beetle, Passat TDI forum' started by mgoff5000, Mar 18, 2017.

  1. mgoff5000

    mgoff5000 Member

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    Jetta is on H&R Sport/Koni Yellows, Skid plates on Jetta/Passat, BSD and cam replaced on Passat
    I've been reading
    http://www.myturbodiesel.com/wiki/v...ustment-repair-replacement-on-tdi-engine-mk4/

    I'm at the troubleshooting step of disconnecting the actuator rod from lever to check for free movement of the vanes. I've gotten my thumb on the lever and can barely move the thing, but I'm also fighting the actuator spring.

    What's the easiest way to free up the lever for testing? Just the circlip, just the 2x10mm actuator bolts, circlip + bolts? Looks like tough visibility, even with the hoses out of the way in the picture.
     
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  2. Seatman

    Seatman Well-Known Member

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    I look in from the right side of the car and get a bar or something down onto the lever and push. Bit awkward but it works eventually lol

    Or get up to it from below and pull down

    Other option is yeh, 2x10mm nuts and circlip
     
  3. Live4Snow

    Live4Snow Member

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    Was the car warm when you tried? Getting the turbo hot is supposed to help make it easier and then obviously wear a good set of gloves.
     
  4. luxuryrules

    luxuryrules Member

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    With everything assembled, put a 9/16" box wrench on the vnt lever on the turbo. Should be able to move it with one finger, even against the spring and actuator.
     
  5. mgoff5000

    mgoff5000 Member

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    Thanks guys, all good tips and info. Not sure I got the wrench on there as luxuryrules intended, but there is nothing one finger about the movement I'm getting either with my thumb or a wrench on the lever. And it does seem to vary with degree of warmup as live4snow mentioned. I'll get a fresh circlip and see how the lever moves when free of the actuator. I would love for it to be the actuator, but we'll see. I've got this sinking feeling there is some disassembly coming up. The job may be rated 2/5 but I'm guessing it's a full weekend for me if I'm lucky.
     
  6. Seatman

    Seatman Well-Known Member

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    I always get them moving on the car, does fine for a good while which is handy if you're in the winter season. That's when I tend to find issues popping up lol

    Its just getting something decent on it to get it moving to start with.

    If the actuator isn't sticking I'd maybe try lubing the vnt lever and seeing if I could get it moving.

    Unless the weathers decent of course
     
  7. mgoff5000

    mgoff5000 Member

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    Jetta is on H&R Sport/Koni Yellows, Skid plates on Jetta/Passat, BSD and cam replaced on Passat
    So I ran the VCDS Block 011 N75 cycle under basic settings on VCDS.
    I visually see the actuator rod moving in and out. Couldn't gauge full travel or not.
    Here's my question though, the logged pressure doesn't change at all during the test. Is that expected or should I see a boost change when the N75 is in the ON position and valve is 99%? The underlying issue is overboost, which seems due to a lagged turbo response to the N75 change.

    N75.png
     
  8. Riccogolf

    Riccogolf New Member

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    Hi mgoff5000, I can only give you a comparison against two sets of readings off my standard 150ARL engine, but yes I believe you ought to be getting more difference in boost numbers on/ off....but I notice also your revs at 903 rather than 1400 which I thought was standard for this test and could be the cause of lack of boost...maybe I'm missing something...

    After I had replacement turbo fitted I was getting (at 1400rpm) OFF 971mbar, and ON 983mbar...and a very very poor performing car....
    The VNT arm adjustment nut was tweaked and ended up with (at 1400rpm) OFF 1006mbar, and ON 1263mbar....and a lively car...

    I'm sure there are other reasons for lack of boost in this test, but perhaps my numbers will be some form of guide.

    Good luck with it.
     
  9. mgoff5000

    mgoff5000 Member

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    Yeah, I thought the RPMs were meant to be higher too. For some reason the Ross-Tech wiki just doesn't read easily for me
     
  10. mgoff5000

    mgoff5000 Member

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    After a bad week of overboost codes, I finally disconnected actuator and yep - the turbo vanes lever is anything but "free and smooth operation" I'm getting started on taking it out while I contemplate whether I really wanna clean it or just get a new one. Probably go VNT17 for tuning options down the line. Taking off the actuator was pretty easy so glad I got in there and diagnosed what was going on!
     
    Live4Snow and Riccogolf like this.
  11. mgoff5000

    mgoff5000 Member

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    Jetta is on H&R Sport/Koni Yellows, Skid plates on Jetta/Passat, BSD and cam replaced on Passat
    The wonder of letting PB Blaster sit a full day. I was pretty convinced I couldn't open the 17 year old VNT15 for cleaning. Got up the courage to spend almost $3k on the hardware for a proper Stage 4 tune - but tonight a couple taps and the VNT15 opens right up. Now it's a tougher decision. I think I can be up and running for just a few replacement seals/gaskets. Different car though :)
     
  12. mgoff5000

    mgoff5000 Member

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    2000 Jetta 5-spd, 2004 Passat Wagon
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    Jetta is on H&R Sport/Koni Yellows, Skid plates on Jetta/Passat, BSD and cam replaced on Passat
    So I decided to try to see if I can get more life from the VNT15. I cleaned it per the wiki guide. It moved well after cleaning the upper part with the ring so I didn't take out the vane mechanism. Got it bolted back up and just waiting on the various new gaskets to arrive to reinstall and test it out.
     
  13. mgoff5000

    mgoff5000 Member

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    2000 Jetta 5-spd, 2004 Passat Wagon
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    Jetta is on H&R Sport/Koni Yellows, Skid plates on Jetta/Passat, BSD and cam replaced on Passat
    Wow, that job was a beast. Got it all back together and turbo hasn't self-destructed after 20 miles or so. Logged some hard uphill runs and didn't get overboost. Unfortunately I did test the actuator off the turbo and it seems to stick for a few inches of pressure coming back from the stop. Since the turbo is moving well, next overboost code will prompt an actuator replacement. At least that's relatively easy to do.

    Never realized how much I loved the longitudinal engine in the Passat until I spent a day and a half in the back/bottom of engine bay on this ALH! While working upside down and blind (from above) was super fun allow around, that oil return line bolts on the turbo and the charge air connection at the turbo were a good 3-4 hours of frustration! Just watch the day melt away. To anyone researching this (and I'll update wiki eventually) I suggest working from above AND below on this job. I kept talking myself out of putting the car up but it really would have saved a ton of time and bruises!
     
  14. mgoff5000

    mgoff5000 Member

    Joined:
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    Car:
    2000 Jetta 5-spd, 2004 Passat Wagon
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    Jetta is on H&R Sport/Koni Yellows, Skid plates on Jetta/Passat, BSD and cam replaced on Passat
    Here's a log of the boost control after the turbo was cleaned. There is now a much better response to the N75 than previously.


    CleanedTurboBoost.JPG
     

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