Help Please - Mk4 1.8 20V T - Camshaft Sensor Problems

Discussion in '1.8 & 1.8T' started by Dave, Aug 20, 2017.

  1. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    Hi folks,

    I am getting a fault code on the Camshaft Position Sensor - Signal too high!
    I checked the actual timing and it shows timing at approx. 23 deg before tdc. 6 to 12 deg is correct.

    I had problems deciding which gap in the Exhaust Camshaft Sprocket to fit roller #1.
    The manual is very imprecise: "Slightly offset to the inside"

    I decided to use the red marked gap, which is about 5 deg to the left of the notch!
    The blue one is approx 22 deg and I considered this more that "Slightly"!

    BUT. The notch in the camshaft would not sit exactly inline with the arrow on the cam bearing top. It was about 4 deg towards the manifold side.
    The notch in inlet cam aligned perfectly with the arrow, but if I tried to turn the ex. cam to line up it returned to the "slightly" off centre position, shown in the image, due to spring pressure on the lobes.

    Of course, the TDC marks on the top pulley were thus slightly out of line.
    The pulley mark was approx. 4 deg to the left of the mark on the cover, just as the cam was.

    I assumed that this would be OK and that the VVT system would take care of it when under oil pressure!

    I had great difficulty fitting the timing belt as it was very tight even with the tensioner fully compressed.
    Lainey was watching the TDC mark on the flywheel and it moved out of site easily!
    It took about 10 goes to get it on and the flywheel mark still to be visible, although a little off centre.

    Thoughts pleas.
    Regards,
    Dave.








    IMG_0277.jpg
    camshaft notch.jpg
    2010-06-10_201333_Untitled.jpg
     
    Last edited: Nov 28, 2017
  2. notenoughtime

    notenoughtime Moderator Moderator

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    I had the same issue setting up the old head on the beetle what seems incorrect and to the eye wrong is actually right

    Time it up with the blue mark
     
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  3. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    Thanks Carey.

    But. Damn! Damn! Damn!!!!!!

    The stupid manual should state the actual angle that the sprocket is offset!

    This means more expensive gaskets!

    Dave.
     
    Last edited: Aug 20, 2017
  4. notenoughtime

    notenoughtime Moderator Moderator

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    Why more gaskets Dave?

    Simply remove cam cover etc and re-time and bolt back together
     
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  5. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    I have decided to do that as the gaskets are only 3 weeks old and so will not be distorted!
     
  6. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    What's weird is:

    When it starts, after 2 or 3 attempts, it runs perfectly!

    Also. Porting and polishing the head must have increased the efficiency by about 10% as Lainey used to get readings of around 35 mpg on a run, she now hits 40+ mpg!

    So. Has the power increased by 10% as well.

    If so, it must be up to around 145 kW!?

    When I have sorted the timing, I'll run acceleration tests with the VCDS running.
     
  7. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    The timing is as Carey said.
    Validate by counting the chain rollers between the marks.
     
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  8. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    Thanks Eddie and Carey.
     
  9. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    Still have the same problem!

    Well folks. I still have problems.
    The timing is still anything up to 10 deg. advanced at tick-over, and 18 deg. advanced at high revs.
    Just as they were on June 10th.

    Audi_Log_page_001.jpg

    I changed the 16th chain pin the the 'blue' gap as advised above.
    No change to the fault code!

    DSC00113.jpg

    The crank is definitely at TDC. The timing marks are spot on!

    DSC00111.jpg

    So I bought a new Hall Sensor andfitted it, but there was no change.

    I swapped out the Hall sensor shutter wheel from the APY one, marked 06B, to the AUQ one marked 06BA.
    No difference!

    I checked the wiring from the Hall Sensor plug back to the ECM and all wires have continuity.

    I had used the cams from the APY cylinder head wrongly thinking that they are identical to the AUQ ones.
    The AUQ cams were very slightly scored on the bearing journals and there were small areas where aluminum had welded itself to the journals.
    As it turns out the inlet cam on the APY is a different part number to that from the AUQ.
    Also. The APY is engraved 'L' whilst the AUQ marked 'L-'.

    So. I cleaned up the journals on the AUQ cams with well flatted 2000 grade wet & dry paper, Solvol Autosol and uber fine polishing tape.
    These I then fitted.

    Turns out that
    I am getting quite good at removing the camshafts.

    IMG_0343.jpg
    IMG_0339.jpg
    IMG_0338.jpg

    Still the same fault code!

    Any suggestions as to what to look at next would be much appreciated!
     

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  10. notenoughtime

    notenoughtime Moderator Moderator

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    Hey Dave is Timing mark on cam sprocket correct? Im sure it is but I'm checking lol
     
  11. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    Yes the timing belt sprocket mark is spot on.
    It's a new sprocket as the original sprocket had the key sheared off when the camshaft seized!
    It would not matter anyway Carey as the notch in the exhaust cam lines up with the arrow on the chain sprocket bearing cap.

    I actually managed to get the timing belt on one tooth out, at the crank, during second re-build with the APY cams.
    I got the same resulting fault code and the same BTDC figures.

    It seems that no matter what I do, be it one tooth out on the chain, or one tooth out on the belt, the results don't change!?

    Which is very weird!?[:s]

    I am wondering if it's the crank position sensor that's wrong?
    It's a bu99er to get to the sensor plug as it's up on the oil filter housing.

    I might try disconnecting it! Which means a session of nausea and headaches, on my back, under the engine!
     
  12. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    I have been searching the web for weeks now regarding the problem and came upon this today!
    Identical problems, and what reads like a very informed reply!?

    Cam Sensor 2.png

    Earlier on the advisor mentions that cable continuity checks do not necessarily mean a good signal is carried.
    Also, as he says, just unplugging the sensor does have exactly identical results.

    Now. The Hall Sensor I bought was a cheapo.
    But his comments regarding signal are interesting.
    I must admit that the signal cable is not very flexible close to the sensor as though suffering from heat, or age, hardening.
    I'll have to open up under the windscreen again tomorrow., and check resistance!
    If it is a cable fault hopefully it's in the first 100mm, or so, from the sensor!

    Funnily enough I have just repaired broken cables in the hatchback looms, where they flex in the rubber boots.
    We now have central locking and a boot light!

    Thinking about it.
    The cables to the sensor are quite likely to be the source of the problem as they have been pulled about on quite a few occasions!
     
    Last edited: Sep 25, 2017
  13. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    Damn - damn - damn

    Just bought a complete BAM cylinder.

    The one Carey gave me, for which I am very grateful, had some oval valve seats, with cracks between them, and eroded water ways.
    I was so desperate at the time that I used it with the intention of finding another, better, head, which I have now done.
    I shall refurbish it, and polish the ports, over the winter. It will mean another 200, or so, for valve seals, gaskets and bolts, but I shall be it's not going to let me down.

    I was somewhat surprised, and not a little upset, to find that the 16th roller of the cam chain is in the sprocket gap marked 'red' in the first post.
    Thus it would appear that moving the 16th roller to the 'blue' gap was wrong!
    I should have realised that it was wrong because the original 'red' alignment, and the polished ports, Lainey was reporting an easy 35 mpg. Lucky if she can get 30 mpg on 'blue'.

    So, I have until the 7th of January to sort it ready for the NCT test.
    But. It is flipping cold and flipping wet here, and really I don't fancy doing the job one little bit! It's a cam chain swap plus the hall sender re-wire!





    IMG_0394.jpg
     
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  14. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    More damns !!!!!!!!!!!!!!!!!!

    If you look at the photo on the previous post you will see that the EGR port has a ball bearing ball in it.

    It looks like hours of Dremel work to gring it out!
     
  15. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    AMK/BAM EU3 cylinder heads to not use SAI. The hole at the rear is for the SAI valve as fitted to other castings such as the AUM, AUQ, AJQ and so on.
     
  16. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    Sorry it's not EGR it's SAI.

    As I said. I have to get the flipping bearing ball out!
    It will be a long tedious job!
     
  17. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Can be calibrated out of the engine calibration and removed completely.
     
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  18. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    Ta so for the advise Eddie, but I want to keep the system original.

    If I grinding is not possible I will have to find a company with a spark erosion machine.
     
  19. Dave

    Dave *Very Smart* Pedantic Old Fart Paid Member

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    Changed the cam chain back to the original alignment.
    Just have to put the new signal wire into the Hall sensor plug now!

    Cut out the bearing ball from the BAM head.
    It took just one hour, mainly because I used a tiny carbide cutter that Justin sent to me about 10 years ago!

    Thanks once again Mushy!
     
  20. Sirguydo

    Sirguydo Fastest milkman in the West Paid Member

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    Well done , hope things are on the up then Old Man :thumbup:
     
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