gallons/min fuel leak(gusher)

[bcbio]

OK here is one I can't find an answer to. Riding around yesterday got out smelled fuel, looked under truck and major fuel leak coming around trans and oil pan. Cut truck off fuel stopped after a few seconds. I have an air dog, restarted the truck no fuel leak for a few seconds and then the gusher. I checked here and found to look in the valley of the engine because of where the fuel is running. The leak is in there some where but I don't know where. I have no codes, and the truck will run once started like normal. Doesn't like to start, long crank but once running runs fine. I am hoping that it is a return line busted on the cp3 but I can't see the thing. This thing is blowing 1 to 2 gallon a minute when the truck is running if it was my cp3 gone bad the truck wouldn't run I wouldn't think right?
BCBIO

 

[dmaxfireman]

look at the soft line going from the filter head to the cp3.

 

[bcbio]

Sorry new on here I had to bypass the fuel filter and I added an Air Dog, the primer went bad and was leaking fuel everywhere so I could pay 700 for a new one or 500 for an Air Dog. I will dig around and see if I can find where the fuel line goes to the cp3.

 

[emiller3]

There is also a couple of soft lines in the valley to check out.supply and return coming of the cp3

 

[bcbio]

Can you see them from the top or will I need to take all the stuff off the top of the motor.

 

[bcbio]

can you pull a duramax with an allison trans without damage while in neutral

 

[Js95gt]

Can't pull it very far without removing driveshaft.
Now, what year is your truck?
Have seen quite a few 06 and newer trucks blow the freeze plug out the bottom of the injector pump and still run but have a MAJOR fuel leak in the valley. Cause is internal failure of pump and it usually sends metal through the entire fuel system causing major damage. GM actuall released a bulletin and it requires replacing the pump, rails and all 8 injectors, drop and clean fuel tank.

 

[bcbio]

I have about 10 miles to get to the shop I have a 2003 you think I need a tow truck?

 

[dmaxfireman]

do not drive it. get the tow if you are bringing to a shop

 

[Js95gt]

Is it 2wd or 4wd?
If 2wd just remove the rear shaft and pull it.
If 4wd put the tcase in neutral and pull it.

Haven't seen many injector pump failures on 03 so more than likely it will be a return line that busted if it still runs.

 

[blk smoke lb7]

Start it up and get over the motor with a bright flash lite you should be able to get an idea where its coming from which side of the trans is it coming down? check the return line banjo fittings theres 1 in the back drivers side and 1 in the front passenger side there are 2 rubber lines that come off the cp3 lift the wireing harness while its running and see if the rubber is spraying out if its laking as much as you say shouldnt be hard to see where its coming from.Update this and let us know what you got.

 

[bcbio]

well it is at the shop!! I started it up and took off called my wife on the phone and told her to pick me up. She didn't know where the shop was so I told her to follow the fuel. She said she had no problem finding me, every stoplight had a puddle the size of the hood of the truck. I still didn't show the check engine light so I guess I have no codes, it was hard starting but ran fine. I hope it is a return line the fuel is coming down the passenger side of the trans, I never was able to get up there and look for the leak. It took a quarter of a tank of fuel to make the 10 mile trip.

 

[Burn Down]

What part of don't drive it did you not get? For the sake of your fuel injectors you better hope that it is just a return line & not a pump failure. I have seen with my own eyes a LB7 pump GUSH fuel out of the valley just like yours. Guess what, the pump failed and blew the soft plugs out of the case of the cp3, his truck would start and run to. Now that truck needs new injectors... Hope your lucky.

 

[tinman22]

how about the fire hazard if the fuel hit the exhaust just right. then again if it burned he wouldn't have to worry about fixing it

 

[bcbio]

I will let yall know probably tomorrow it will take them a while to get to it. I hope it was the return but after talking to the guy this morning he is thinking the pump. I can only hope and pray it is a return line. What does it do to the injectors if it was the pump? I still have no codes so he said the high pressure side of the pump was working but the other side I guess the return side was probably bad. I will know tomorrow for sure..

 

[Burn Down]

The fuel pump works from 0-26000 psi depending on the year of your truck. So, say the ecm needs 5000-10000 ish for idle and part throttle. Your pump can be failing and still put out enough pressure to start, run & do some part throttle driving... WOT I bet would pop a low rail pressure code.

My point is, as the pump is failing it is/can be sending tiny bits of the pump out of the high pressure side straight into the injectors. NOT GOOD!

As I said before, I hope your lucky. You must be some what lucky because as stated above you didn't catch it on fire

 

[bcbio]

They are still not sure what it is but leaning towards the pump, said the lines were near the top and didn't see fuel coming from them they would do more testing and looking tomorrow. So whats the best place and price for an LB7 CP3, can you get rebuilt pumps or is 900.00 the best I can expect?

 

[blk smoke lb7]

I think you can get 1 from Darryl and Henry for pretty cheap they have remans and new

 

[bcbio]

got one for 760.00 that was in town and didn't have to wait they are putting it in now I hope I didn't pay to much??

 

[bcbio]

Well I did it good all three plugs blown out, and a big pile of metal in the valley. They are flushing everything now. They were taking the gear off the front of the old pump and it was stuck probably spun a little bit. The gear cracked all the way from the hub to the teeth so I am waiting on a new one. Boy what a mess, they said they didn't see metal in the rails but they are flushing them anyway. I can only hope nothing got in the injectors.