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512 BBi tdc sensor

Discussion in 'Boxers/TR/M' started by pshoejberg, Oct 14, 2020.

  1. pshoejberg

    pshoejberg Formula 3
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    Dec 22, 2007
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    I hope some of the expert can help me on this one. I'm fault finding on my 512 BBi and suspect the that the tdc sensor could be defective (See picture below). I have tried the search function but are unable to find any info related to the sensor. Are the anyone here that have any experience with the sensor; is it prone to fail?, how can I check it's correct function? I have measure the resistance to 1.1K ohm across the sensor, is that an acceptable value?

    Thanks in advance, Peter


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  3. turbo-joe

    turbo-joe F1 Veteran

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    you may check this sensor with an osci in the distributor
    I will check tomorrow the resistance from my sensor in the car and also the other one I have in stock
     
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  4. turbo-joe

    turbo-joe F1 Veteran

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    just checked my 2 I have here
    one has 1,15 k ohm and the other 1,17 k ohm
    so your one seems to be ok
     
  5. pshoejberg

    pshoejberg Formula 3
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    Thanks Romano, much appreciated! My sensor seems to be fine then....Then I have to look other were. I feel an ever so slight hesitation when the car is accelerating all the way up from idle to around 3000 rpm's. Very strange, the car starts and idle's perfectly and it runs like a dream above 3000 rpm's.

    Best, Peter
     
  6. turbo-joe

    turbo-joe F1 Veteran

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    you may check the gap between the 12 point/nose disc ( sorry, don´t know how to say other ) and this induction pick up.
    you have a BBi, so I think it is more a problem of the injection than the ignition.
    do you have the possibility to use an osci?
    what about when you only raise the rpm without driving? same problem up to 3000 rpm? if yes then you will see some on the osci what is not ok. if not then I think injection ( to lean ) because without load it not need much fuel
     
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  8. pshoejberg

    pshoejberg Formula 3
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    Thanks for the input. I have a oscilloscope from back when I was a certified radio amateur (I long ago!). I should be able to hook it up and have a look on the wave structure should it be necessary. The engine pulls nicely up from idle to +5000 rpm in neutral gear and are very responsive with no misses at all. It is only under load that I feel a slight lack power / hesitation. I know many Ferrari lowers are saying that these cars should be driven with rpm higher than 3000 at all times, but I want it to be able to pull strong from idle and up i high gear. Tomorrow I will focus on the fuel / injection side as I also suspect a slight lean condition. First check will be to measure the CO concentration and then look for vacuum leaks.

    Best, Peter
     
  9. turbo-joe

    turbo-joe F1 Veteran

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    thx for the fast responding peter
    so as I already have written: I think it is a fuel problem, getting less fuel
    you have this problem below 3000 rpm always - so it does not matter if the engine is warm or cold - or only when cold?

    before you will test a lot of things: put some fuel in a spray bottle and spray this fuel on the inlet manifolds and all parts from the engine what belongs to the intake, so from the fuel distributors until the gaskets between cylinder head and intake manifolds when the engine is idling. if the rpm´s will change then you know the engine sucks wrong air somewhere. but only do this when the engine is not too warm. and keep a fire extinguisher beside ;)
     
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  10. Newman

    Newman F1 World Champ
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    Its not the ignition pickup thats faulty. I would verify the advance curve is correct, sensor plate position and HC settings are correct.
     
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  11. Dave Bendl

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    This is interesting. I had a "stumble" under load between 2700 - 3000 RPM with my BBI. Come to find out it was 1 of the 12 P/N 109357 Spark Plug Extensions that intermittently was failing. The name of these is deceving since they have internal resistors to prevent ignition/radio noise. 11 of 12 measured 10K Ohms but the 12th was dead. New P/N 109357 Plug Extensions measure 5K Ohms so I replaced all 12. These are not expensive at $10 each. I have posted photos. Note the cutaway. The resistor is the black piece. After cutting the bad 109357, I found the resistor is held in place with spring tension. Moving it regained continuity. Give all 12 a check. It solved the issue in my BBI. Please excuse my old school analog multi-meter.
     

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  13. Newman

    Newman F1 World Champ
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    Those plug extenders can also leak electricity through the side grounding in the plugwell. Look for a pinhole through the side adjacent to the female terminal.
     
  14. Dave Bendl

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    I agree. I gave mine a full visual when I did my last major then again when I recently replaced the ignition wire set but no signs of ignition blow-through pin holes in the plug extenders. Best bet is to test with a multi-meter. I'm still using the original Dinoplex, not as powerful as an aftermarket unit.
     
  15. Newman

    Newman F1 World Champ
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    My original 79 Dinoplex gave up this past April and after some trial and error it was determined to be the large bolt-on module on top of the main unit that was at fault. It didn't make the whine anymore. I ended up putting an MSD 6A on it and even with a good dinoplex it didn't run as well as it does now.
     
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  16. Dave Bendl

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    That's great Paul, but this thread is about what might help Peter with his BBI issue. If an MSD will fix the problem with his BBI, please offer him diagnostic assistance. As for me I'll keep the Dinoplex for originality. But that's just me.
     
  17. pshoejberg

    pshoejberg Formula 3
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    Thanks for all inputs guys...much appreciated. I changed to new ignition wires recently and tested all the plug extenders with my ohm meter and inspected them visually for pin holes....they are all good. I changed to a MSD ignition recently and that have sorted a few issues I had with the old Dinoplex. Back to my "issue" and related fault finding....I measured CO the other day and both sides are showing 1.6%. I tried to increase both sides slightly to 1.9 % just to do something, but it didn't help with the hesitation problem. Next up is looking for air leaks, then i will check then distributor sensor position relative to the tach wheel as per newman recommendation. I'm running a new distributor but kept the old rotor...Could that be a problem?

    Best, Peter
     
  18. 2dinos

    2dinos F1 Rookie

    Jan 13, 2007
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    Hi Peter,

    I concur w Paul on distrib advance. It's the age as much as miles. Also, the lube gets destroyed from the ozone / plasma generated by the 12 cyl caps. 6 sparks / turn. Also, I've heard complaints from several folks on those plug extenders arcing.

    BTW: You posted your beautiful fitment of the MSD 6 in you AEC-104. Is this when the problem started?

    How we love them so!
     
  19. pshoejberg

    pshoejberg Formula 3
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    The hesitation was also apparent with the Dinoplex box. If anything, the change to new MSD ignition have improved the situation. I have cleaned and re-lubed the distributor weight mechanism and I measure the correct advance with my strobe light going from idle to 5000 rpm. Also the hesitation is constant from idle and up to above 3000 rpm (The car is stumbling in high gear, if you know what I mean), so it doesn't feels like like the weights are hanging and suddenly moving. I have also changed to new injectors....I made one mistake when I serviced the engine though; I plated the fuel injection steel pipes without plugging off the openings...I wonder if some dirt / corrosion have started to block the injectors...? Anyone have any experience with this?

    Best, Peter
     
  20. pshoejberg

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    I just changed back to the old steel type injectors and test ran the car. Still same issue with slight tumble under load at low rpm's....That leaves out dirt in injectors. I cleaned all the injector piping a couple of weeks ago and drifted them all with a wire so the engine is getting fuel. Damn the car is running so nice when I drive it a bit harder, extremely powerful and pulling like a train...maybe I'm just too nitpicking?

    Best, Peter
     
  21. Newman

    Newman F1 World Champ
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    Veering off topic somewhat does help all of us and it would seem he agrees the car runs better with the MSD. The original units are inferior and people should know this. The rebuilt units I put in cars look correct and even reproduce the original sound.
     
  22. Newman

    Newman F1 World Champ
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    What's your HC number at idle? Dont rule out tuning by ear either. The engine will tell you if it likes it or not. If you're too rich you'll get the rolling idle after a quick throttle blip.
     
  23. pshoejberg

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    #20 pshoejberg, Oct 19, 2020
    Last edited: Oct 19, 2020
    Off topic and sidetracking is all okay in my opinion...This is open forum and anyone is welcome to tell a story or share any issues. Anyway, I have now adjusted the CO back to original figure and re-installed the new injectors just to reset my fault finding. I have then opened up the distributor and again inspected all the parts. I'm a bit embarrassed to reveal the status on my inspection and i can not really explain my previous lack of attention when i re-lubed the unit. This is my findings:

    - Outer bearing shut (Noisy, full of friction and corroded)

    - The two nylon sliding bushes are worn to the extend that they are starting to crack.

    - The two "long" springs in the weight mechanism are of different length and spring force causing one of the weight tabs to never have contact to the round steel housing before the short and hard spring takes over. Someone must have tampered with the ignition, this is also indicated by the condition of the screws!

    My best guess, based on above observations, is that the advance curve is incorrect and possible also erratic. This could be my problem. Newman, your first guess might be spot on, unfortunately I don't have access to a distributor tester, that would have indicated a problem I think....Now I wish that I had gone completely digital and bought the MSD with programmable advance. Anyhow I need to go shopping for spares, I do not see any distributor spares at either Superformance Maranello Parts, anyone that knows if the nylon bushes and springs are available anywhere?

    Best, Peter


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  24. turbo-joe

    turbo-joe F1 Veteran

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    those nylon bushes are also on some distributors brass and you can make them by yourself.the 4 springs are all different and to adjust the advance it needs additional smal shims/washers, but without a distributor bench it is nearly not possible to fix this. or you have always to remove the distributor, dismantle and put together and in again. if you not have experience then you need 1 day, even more. I would never do this. go to a shop who has a distributor bench, pay a little and then all is ok. or come down the weekend to me and you can do it on my bench - for free when you do it ;)
    the pins where the weights are on are ok? also the borings/holes in the weights?
     
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  25. pshoejberg

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    The pins, weights and small cylinders are all ok and I noticed some very fine shims as well. At least one spring is toast / wrong type. I have some brass bushes I bought for my Dino, I will check if they fit. Who knows, maybe all the components from a Dino distributor fits...I have a complete new set of spares lying around somewhere. I will check and report back. I realize that I need access to a distributor bench. I will search locally, but if I fail you better brew some coffee and warm up your test bench Romano.

    Best, Peter
     
  26. pshoejberg

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    I found my set of new produced Dino spare distributor guts (See pic below)......Apparently everything fits with only minor adjustment. The distributor mechanics are basically the same dimensions from my 69 Dino to the 84 BBi.

    Best, Peter

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  27. turbo-joe

    turbo-joe F1 Veteran

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    no problem, have only to undust the test bench.

    but: just now don´t know how to test a pointless distributor? :( until now I only adjusted distributors with points. have to think over how to do this with the inductiv pick-up

    who can help me?
     
  28. pshoejberg

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    Don't worry too much before I have checked possibilities locally. I have a fair good network amongst some pretty knowledgeable gear heads with a lot of nice tools covered in dust...:). I just ordered the bearing in Uk, so with a little luck I should hopefully be ready to test the engine with a more stable distributor within a few days. I'm still annoyed that I slipped this disaster through the quality control some month ago. I have only driven around 1000 km this summer, so I can not blame resent wear and tear.

    Best, Peter
     

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