I just bought a 2001 lb7 last week and a massive fuel leak started the other day. The leak comes from the back of the engine, and drips from the back of the oil pan onto the ground. I replaced the fuel pressure regulator and the two rubber return lines above the cp3, drained the oil and no diesel fuel came out with the oil. I checked the fuel filter, fuel return lines to the tank and I still can't determine where the leak is coming from. What could be causing this issue??? I'm stumped. Any help would be great.
Massive fuel leak?
- Thread starter BigOAnderson
- Start date
Pull off the gpcm and the little things on top of your driver side valve cover and take out your pass ic piping. Tighten down all of you injector fuel line fittings. Then put a dab of fresh silicon where the hard line goes in each fitting then check for the leak. I have had the exact problem.
2004 Silverado Cali lb7, Airdog ll 165, fresh sticks at 325k, kory Willis tune on v2 for daily driver, 33x12.5 nitro at on 20 inch American steal wheels, modded factory air box, Profab Intake Horn, Batmo Wheel, Turbo port and polish, Full EGR Removed w/ fed belt, 3.5 inch MBRP Downpipe, Full five inch MBRP Exhaust w/ 6 inch tip, 8mm lbz cp3 pump, Dual Yellow Top Alernators, High Output Alternator, Cognito Pittman and idler w/ support kit, Cognito Contol arms, Drilled and Slotted Rotors on all four Corners, FEd Y Bridge.
2004 Silverado Cali lb7, Airdog ll 165, fresh sticks at 325k, kory Willis tune on v2 for daily driver, 33x12.5 nitro at on 20 inch American steal wheels, modded factory air box, Profab Intake Horn, Batmo Wheel, Turbo port and polish, Full EGR Removed w/ fed belt, 3.5 inch MBRP Downpipe, Full five inch MBRP Exhaust w/ 6 inch tip, 8mm lbz cp3 pump, Dual Yellow Top Alernators, High Output Alternator, Cognito Pittman and idler w/ support kit, Cognito Contol arms, Drilled and Slotted Rotors on all four Corners, FEd Y Bridge.
It leaking from the cp3 is what I was afraid of. It'll have to wait until tax return time if it is unless I can rebuild it? Any recommendations from where to get a cp3 and is it worth getting an aftermarket new one over a reman for a stock motor considering the price difference? Go fast parts won't be added for a while.
Is it tuned? If so get an lbz pump from Lincoln diesel. If not get a lb7 pump. No rebuilding it. They're like 700. Or just buy a good used one from here for like 300.
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I was just into this last week. The supply and return lines run deep under the resonator and other parts. You can check the supply line by disconnecting over by the brake resovoir and disconnecting again at the fuel filter inlet. Cap the disconnected hose at the inlet and then pull a vacuum with a mighty vac on the other end and see if it will hold.
It's a pretty quick test. Maybe 10 minutes to get those lines off and no parts need to be removed.
If you can't hold a vacuum you know there's a leak on that line. It's a straight shot (no T's) from that quick disconnect by brake res to the ficm and back out straight to the fuel filter inlet.
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It's a pretty quick test. Maybe 10 minutes to get those lines off and no parts need to be removed.
If you can't hold a vacuum you know there's a leak on that line. It's a straight shot (no T's) from that quick disconnect by brake res to the ficm and back out straight to the fuel filter inlet.
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I ended up bypassing that hard line that runs through the motor valley. I ran a continuous rubber fuel line from the tank sending unit and along the firewall direct into the ficm. The metal lines have been suspect to me. They are rusting everywhere along the frame. It's not gorgeous but now I know I have a straight run to the tank with no breaks or couplings. It won't have to be considered as a factor when troubleshooting fuel delivery issues.
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Nope, no tune. Also, if the injector pump is leaking, where exactly could it be coming from on the pump? It seems that my fuel is flowing from underneath the fuel pressure regulator. It seems possible that the leak could just be coming from the fpr instead. I guess I'll have to investigate more.
X2
2004 Silverado Cali lb7, Airdog ll 165, fresh sticks at 325k, kory Willis tune on v2 for daily driver, 33x12.5 nitro at on 20 inch American steal wheels, modded factory air box, Profab Intake Horn, Batmo Wheel, Turbo port and polish, Full EGR Removed w/ fed belt, 3.5 inch MBRP Downpipe, Full five inch MBRP Exhaust w/ 6 inch tip, 8mm lbz cp3 pump, Dual Yellow Top Optimas, High Output Alternator, Cognito Pittman and idler w/ support kit, Cognito Contol arms, Drilled and Slotted Rotors on all four Corners, FEd Y Bridge.
2004 Silverado Cali lb7, Airdog ll 165, fresh sticks at 325k, kory Willis tune on v2 for daily driver, 33x12.5 nitro at on 20 inch American steal wheels, modded factory air box, Profab Intake Horn, Batmo Wheel, Turbo port and polish, Full EGR Removed w/ fed belt, 3.5 inch MBRP Downpipe, Full five inch MBRP Exhaust w/ 6 inch tip, 8mm lbz cp3 pump, Dual Yellow Top Optimas, High Output Alternator, Cognito Pittman and idler w/ support kit, Cognito Contol arms, Drilled and Slotted Rotors on all four Corners, FEd Y Bridge.
Found the problem, turned out to be a torn o-ring from when I replaced the fpr... caused me quite the headache lol
