Under hood fuel leak

Discussion in 'Heavy Truck & Equipment Forum' started by GMC guy, Jan 21, 2016.

  1. GMC guy

    GMC guy Hero Member

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    Please fill out the following to ask a question.

    MAKE: gmc c5500
    MODEL:
    YEAR: 2005
    MILES: 250, 000 km
    ENGINE
    : 6.6
    DESCRIBE ISSUE....fuel leak under hood. Shut it off a few days ago. Now it won't start. Doesn't even sound like it's getting fuel
     
  2. billr

    billr wrench Staff Member

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    Any clue where the leak was from? Is this a diesel? Regardless, I'm thinking a fuel pressure test is the first step (after making sure there isn't still a leak!)
     
  3. nickb2

    nickb2 Wrench. I help when I can

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    Try these flow charts would be a first step after tightening all fuel line balancer and return and high pressure fittings.

    You may also have air in the system if the leak siphoned in air. Which may prevent the engine start. Just a thought.

    Screenshot (506).png Screenshot (507).png Screenshot (508).png
     
  4. nickb2

    nickb2 Wrench. I help when I can

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    Here is a diagram of related components. BTW, is the check engine light on? Are there any codes?

    Also do a return pipe purge to see if will start. Prime the line by pressing the plunger on the fuel filter 30 times. Repeat until it starts. The prime system will need to reach 8psi to 10psi by pumping 30 times. It should hold 8psi for two minutes to ascertain primer system is not leaking and in working order.

    Also, a return line that is blocked may cause leaks also. You may also use the first start bleeder valve, #8 in the component diagram below. Pressure may be checked there to see if it holds 8 to 10 psi. Bleeding it is a must. If any air is in there, that pump will have a hard time to start and you can burn out a starter. I have seen stubborn ppl do this in my life.
    Screenshot (510).png
     
    Last edited: Jan 22, 2016
  5. nickb2

    nickb2 Wrench. I help when I can

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    If that does not work, try draining the fuel filter to see if any water is present. and repeat priming and bleed procedure again.

    Drain should be white, located at bottom of filter. It is plastic, so be careful not to damage it. It's not a huge problem if you do, it comes with the new filter which should be changed out periodically anyway.
     
  6. GMC guy

    GMC guy Hero Member

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    Hey guys! It started and ran. I drive it around the block. I checked under the hood and it is not pouring out from what looked (from a distance)like below or behind the left, lower corner of the Control module. It could be from behind ,maybe. Truck runs well but what is behind that injector control module? Is there a hose behind there? Are there rubber hoses that burst? I'll pull it apart Tuesday. It'll just be good to know what to look for. I hope that control module doesn't have a passage through it. It looks expensive.
     
  7. GMC guy

    GMC guy Hero Member

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    I meant to write, it is now pouring out
     
  8. nickb2

    nickb2 Wrench. I help when I can

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    Last edited: Jan 25, 2016
  9. JackC

    JackC wrench

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    Nickb2: I notice above you are using windows 10. You should try the win 10 "sniping tool". It may do what snagit does and more.
     
  10. GMC guy

    GMC guy Hero Member

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    Okay...windows 10 sniping tool...and yes, that leak appears to be coming from the lower left corner. Maybe that banjo bolt is squirting the fuel that way. I will check the bolts. Thank you
     
  11. nickb2

    nickb2 Wrench. I help when I can

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    No Jackc, I am using the 8.1 pro 64bit version.

    I don't know if the 8.1 version has the snipping tool. I will check it out. Thx. But I am having fun with the snagit tool.

    Better than my preschool drawings I have provided in the past!!:eek:

    Well, checked it out, I have to download the snipping tool, but it is available for the 8.1 version. But I will screw around more with the snagit tool, as it is always hovering in the background ready at anytime to snap/snagit without having to open other tiles or programs.

    I like it and it was free. and I find the interface cool and easy to use. Some should try it. Make for a better presentation and more comprehensive.

    I do not endorse it it. I just find it non intrusive. Ok, nuff said about that.
     
    Last edited: Jan 25, 2016
  12. nickb2

    nickb2 Wrench. I help when I can

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    Do you mean the lower left corner of the said module GMCguy?

    Also, did you get it running by priming it, or just a lot of starter abuse? LOL. These can be a bitch when air gets trapped.
     
  13. GMC guy

    GMC guy Hero Member

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    Yes, it appears to be pouring out of lower left corner of control module. And I did pump up the filter thing, and it started quite easy.
     
  14. billr

    billr wrench Staff Member

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    Nickb2, what you posted above using "snagit" looks pretty good to me!
     
  15. GMC guy

    GMC guy Hero Member

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    Just a late late update..after 2 Parking tickets, I loosened some things and looked at the engine from above and saw that the little rubber line from injector to injector was leaking. Replaced it and works fine. Thank you. Thank you.
     

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