Cam and crank sensor issue on cat motor

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Cam Roberts, Jan 13, 2019.

  1. Hulld

    Hulld Road Train Member

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    Agreed
     
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  3. pushbroom

    pushbroom Road Train Member

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    I have only had 2 or 3 trucks ive actually wanted to use a scope on. Always managed to fix them without. Paccar is working with picoscope to make a scope that has all of the can data built in and can say what each message is on the can bus. Supposed to be a mandatory tool for dealers in the next while
     
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  4. spsauerland

    spsauerland Road Train Member

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  5. pushbroom

    pushbroom Road Train Member

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    That does look neat! Price isnt so bad for what it can do
     
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  6. Cam Roberts

    Cam Roberts Road Train Member

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    Just a little update. didnt get to the point of ordering scope. What i did do is remove the crank sensor and look up in the block at the crank gear with a flash light and kept going up in the truck a million times to bump motor. Didnt see anything out of ordenary. So next step was to look at the new sensor. What i did find was a very fine piece of little strand of metal. very tiny that look like a piece of a small wire wheel magnetically held onto the sensor. So i removed that and blow the sensr with some combressed air and cleaned as best i could. There is a little tiny shallow hole in the center of the sensor. Kinda hard to get any metal out of there if there is any unless you can demagnetize it. but anyhow, the small piece of metal must have gotten there from me setting it down on my shop table. put the sensor back in and the truck started normal. so i tried several more starts. on ocassion, it does a very quick miss but nothing like what it was doing. when i repaired half of the crank and cam sensor harness, i did not twist the wires and im reading the cat has them twisted for a reason. Do i redo my work and twist the wires to fine tune this thing and get rid of the slight miss on occasional starts? Also, would that tiny hair sized thickness piece of metal cause havoc on a sensor like that? thanks for your time. give me advise here
     
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  7. bigguns

    bigguns Road Train Member

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    Try searching on here about Cat and/or twisted wires. Something has been posted on here about twisting wires.
     
  8. Cam Roberts

    Cam Roberts Road Train Member

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    Ok I would like to read up on it. Thanks brotha
     
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  9. pushbroom

    pushbroom Road Train Member

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    Twisted wires stop electromagnetic interference. Basically if the wires were ran right over the starter cables and the engine was started, the heavy surge could possibly induce voltage into the speed wires and cause a false reading. Not very common, but can happen. Probably not happening in this case, but it would be best to twist them. Datalinks are twisted and shielded to go an extra step further.

    Clamp 2 wires in the vise and step back how ever many feet you need. Cut em off ,chuck them up in a drill, and spin em up.

    If you are just talking about a short section you repaired that isnt twisted, leave it alone. it will be fine. If its the whole length of the harness, best to twist em.

    More info on a higher reading level https://www.eetimes.com/document.asp?doc_id=1279624
     
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  10. Cam Roberts

    Cam Roberts Road Train Member

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    thanks. thats great info. we are talking about 2 and a half fet of repairs on both sensor setof wires. the wires are all seperated in sets with individual wire looms running down the side of the block and not mingling with other wires
     
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  11. pushbroom

    pushbroom Road Train Member

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    Honestly it probably doesnt matter, but also will only take a little bit of time to twist them and do it right.
     
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