Under hood fuel leak

GMC guy

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#1
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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
 

billr

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#2
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!)
 

nickb2

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#3
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
 

nickb2

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#4
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
 
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nickb2

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#5
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.
 

GMC guy

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#6
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.
 

nickb2

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#8
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GMC guy

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#10
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
 

nickb2

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#11
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.
 
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GMC guy

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#13
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.
 

billr

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#14
Nickb2, what you posted above using "snagit" looks pretty good to me!
 

GMC guy

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#15
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.