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C15 starting issues

Discussion in 'Trucks' started by Juskol18, Jul 31, 2021.

  1. Juskol18

    Juskol18 Member

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    I just purchased a 2005 Pete 379 with a c15 acert. It will not start without a little ether. After some research I read that a common problem was the check valve in the filter head. I’ve replaced both check valves twice with no luck. You can hand prime the pump and you can hear the fuel returning to the tank and it never gets stiff. You can also crank on it and hear it returning into the tank. I have put a fuel gauge on it and I’m only getting 10-15 while it’s cranking over.
     
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  2. stinky64

    stinky64 Senior Member

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    Search the Adept Ape channel on You Tube...everything Cat, this problem sounds like something he has covered before...
     
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  3. DMiller

    DMiller Senior Member

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    Been on his site considerably
    Saved me a load of digging work and bugging all too many people.
     
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  4. JPV

    JPV Senior Member

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    There is a pressure relief valve that goes in from the bottom of the filter head, it should be right in front of where the return line leaves the filter straight up from the bottom. Pull it out and inspect it, it may need to be replaced if it is stuck open but that sounds like the issue if it won't build pressure with the hand pump. Usually you can hear it squeak when it relieves while hand pumping.
     
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  5. JPV

    JPV Senior Member

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    This is what it looks like, could also be a bad oring on it.
    IMG_20210731_075607149.jpg
     
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  6. Juskol18

    Juskol18 Member

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    Yes sir, I have replaced this twice as I was told on another forum I could have bought a bad one. What doesn’t make sense to me is why it’s returning to the tank so easily
     
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  7. JPV

    JPV Senior Member

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    That makes no sense to me either, as far as I know that is the only restriction in the system that makes pressure. I will have to do some thinking on it.
     
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  8. Juskol18

    Juskol18 Member

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    I capped off the line coming from the back of the head that goes back to filter housing, cranked it over and I’m still getting fuel returning to the tank? Would this indicate a internal crack on the filter housing? Could it be leaking by on the hand primer?
     
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  9. Truck Shop

    Truck Shop Senior Member

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    Those hand primers have a check valve also, the check can roll partially over and cause
    all kinds of anxiety. Especially the short stroke model.
     
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  10. Juskol18

    Juskol18 Member

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    I pulled the filter housing off and removed everything from it and found what appeared to be the “bleeder bolt” to be missing an oring on the tip of it. I put an oring on it and now I’m building 35-45psi while cranking but it still will not start without a little shot of ether
     
  11. Juskol18

    Juskol18 Member

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    upload_2021-7-31_13-53-31.jpeg -
     
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  12. Juskol18

    Juskol18 Member

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    Update- i took the filter housing completely apart, cleaned and inspected everything and put an oring on the end of the bleeder screw. I was getting better fuel pressure but only running about 65-75 at idle. I put clear hoses inline to make sure I wasn’t sucking air and getting adequate fuel to the transfer pump, nothing changed.
    I put a new transfer pump and now I’m getting around 70 psi while starting but it will not be crank. I can spray the slightest amount of ether and it fires right up, it doesn’t smoke or anything. With the new pump I’m getting around 90 psi but it is very sporadic my fuel gauge needle is jumping like crazy. (Did this with old pump also)

    I’m lost. What can I check now? Isn’t much left expect injectors.
     
  13. Truck Shop

    Truck Shop Senior Member

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    Thinking back-about 12 years ago we took care of a small fleet of grain trucks. I've only seen this one time and happened on one of those grain trucks.
    Mind you It baffled the hell out of Gayle {the other mechanic} and I. The engine was a 98 6TS 3406-once running it was fine, but would not start without
    ether. Gayle and I went through the fuel system-I had a used cam sensor {this one screwed into outside area of front structure} It fired off. This engine never
    threw a code. We figured the sensor was giving a weak signal on just cranking-that was our best guess. It's still running today on that used sensor.

    I'm not going to say that's your problem-just one I ran up against.
     
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  14. petepilot

    petepilot Senior Member

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    there is a remote possibility the oil pressure sending unit is getting weak also. had one of ours act very much like what is being described. non start with out a little shot then went to limp mode turned out op sensor was bad
     
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  15. Juskol18

    Juskol18 Member

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    even if the gauge is showing oil pressure while cranking?
     
  16. Juskol18

    Juskol18 Member

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    I’m g
    im going to try and find someone with cat ET to hook up to the truck
     
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  17. petepilot

    petepilot Senior Member

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    yes it would show pressure. this went on for some time i really can`t explain it but it would start and run fine did this 7-8 times then went limp mode` diagnostics told us op sensor replaced that` problem went away
     
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  18. JLarson

    JLarson Senior Member

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    C15's can be picky if they have a wonky (technical term) timing sensor, the no start even with good pressure till you give it a lil shot of start in a can is a common symptom of one or the other not working right. Won't always get a code either.
     
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  19. Truck Shop

    Truck Shop Senior Member

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    Series 60 it's called a SRS {synchronization sensor} sometimes those will cause a extended crank time the next time start immediately.
     
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  20. JPV

    JPV Senior Member

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    Oil pressure gauge in the dash has a line to the motor, there is a separate pressure sensor that the computer sees. Et will show what it is seeing as well as cranking speed. Sometimes they will throw a code that is too momentary to store but will be there causing the problem. With et hooked up it will show the active code when it occurs but when it starts it will go away.