Losing Fuel Pressure

[royg]

I have a 2001 3500 Silverado with a 6.0. With the engine off and key on the fuel pressure goes up to 60 pounds and drops steady most times to zero. I took off the main feed line and blocked it off. Checked the pressure at the fuel filter ( using adapter in place of filter) and pressure holds fine, 60 plus pounds. I connected the main fuel line back and lifted the fuel rails and injectors off the manifold and turned on the pump with tech 2 and looked for a leaking injector or cracked fuel rail but no visible leaks. I left the injector conectors on while I did this and fuel pressure still drops to zero. Was i supposed to leave the conectors off the injectors? I have 2 fuel gauges and both drop so its not the gauge. I replaced the fuel pump assy and regulater. It misses intermitently but when ot does Cylinder 2, 6 and 8 misses. 2 and 6 really miss most of the time and 8 every once in a while. I was thinking that 2 and 6 injectors were leaking but they weren't. Did injector balance test and coil test. A little hard doing the balance test but they all drop the same. Ohms on the coils were in specs. Can anyone help me with this problem? Thank you

[wct]

I have a 2001 3500 Silverado with a 6.0. With the engine off and key on the fuel pressure goes up to 60 pounds and drops steady most times to zero. I took off the main feed line and blocked it off. Checked the pressure at the fuel filter ( using adapter in place of filter) and pressure holds fine, 60 plus pounds. I connected the main fuel line back and lifted the fuel rails and injectors off the manifold and turned on the pump with tech 2 and looked for a leaking injector or cracked fuel rail but no visible leaks. I left the injector conectors on while I did this and fuel pressure still drops to zero. Was i supposed to leave the conectors off the injectors? I have 2 fuel gauges and both drop so its not the gauge. I replaced the fuel pump assy and regulater. It misses intermitently but when ot does Cylinder 2, 6 and 8 misses. 2 and 6 really miss most of the time and 8 every once in a while. I was thinking that 2 and 6 injectors were leaking but they weren't. Did injector balance test and coil test. A little hard doing the balance test but they all drop the same. Ohms on the coils were in specs. Can anyone help me with this problem? Thank you

 

Hey I'm wondering dose this truck have an extended crank? This sounds like an internal fuel leak, I would start by carefully removing the pressure regulator and inspecting the 2 o-rings one really small one is more likely the one that you are concerned with. When removed check for any indication that the o-ring was pinched, I recommend using some thing like trans gel or vaseline to lube the o-rings. I suspect that you were on the right track w/reg or pump because that is usually the only things that usually cases this concern. If you wanted to test first i would install fuel line shut off valves in both lines and then get some one to turn the key on while you shut the block offs off then monitor your psi if it still drops then you have a condition w/ reg or injectors but if it holds then you have a condition behind you block off valves such as a pump

I hope this helps you out but I seen these o-rings pinched a few times and done it a time or two my self and it will cause you to go bald from scratching your head until you seen it before. WCT

[royg]

I have a 2001 3500 Silverado with a 6.0. With the engine off and key on the fuel pressure goes up to 60 pounds and drops steady most times to zero. I took off the main feed line and blocked it off. Checked the pressure at the fuel filter ( using adapter in place of filter) and pressure holds fine, 60 plus pounds. I connected the main fuel line back and lifted the fuel rails and injectors off the manifold and turned on the pump with tech 2 and looked for a leaking injector or cracked fuel rail but no visible leaks. I left the injector conectors on while I did this and fuel pressure still drops to zero. Was i supposed to leave the conectors off the injectors? I have 2 fuel gauges and both drop so its not the gauge. I replaced the fuel pump assy and regulater. It misses intermitently but when ot does Cylinder 2, 6 and 8 misses. 2 and 6 really miss most of the time and 8 every once in a while. I was thinking that 2 and 6 injectors were leaking but they weren't. Did injector balance test and coil test. A little hard doing the balance test but they all drop the same. Ohms on the coils were in specs. Can anyone help me with this problem? Thank you

 

Hey I'm wondering dose this truck have an extended crank? This sounds like an internal fuel leak, I would start by carefully removing the pressure regulator and inspecting the 2 o-rings one really small one is more likely the one that you are concerned with. When removed check for any indication that the o-ring was pinched, I recommend using some thing like trans gel or vaseline to lube the o-rings. I suspect that you were on the right track w/reg or pump because that is usually the only things that usually cases this concern. If you wanted to test first i would install fuel line shut off valves in both lines and then get some one to turn the key on while you shut the block offs off then monitor your psi if it still drops then you have a condition w/ reg or injectors but if it holds then you have a condition behind you block off valves such as a pump

I hope this helps you out but I seen these o-rings pinched a few times and done it a time or two my self and it will cause you to go bald from scratching your head until you seen it before. WCT

 

[royg]

I have a 2001 3500 Silverado with a 6.0. With the engine off and key on the fuel pressure goes up to 60 pounds and drops steady most times to zero. I took off the main feed line and blocked it off. Checked the pressure at the fuel filter ( using adapter in place of filter) and pressure holds fine, 60 plus pounds. I connected the main fuel line back and lifted the fuel rails and injectors off the manifold and turned on the pump with tech 2 and looked for a leaking injector or cracked fuel rail but no visible leaks. I left the injector conectors on while I did this and fuel pressure still drops to zero. Was i supposed to leave the conectors off the injectors? I have 2 fuel gauges and both drop so its not the gauge. I replaced the fuel pump assy and regulater. It misses intermitently but when ot does Cylinder 2, 6 and 8 misses. 2 and 6 really miss most of the time and 8 every once in a while. I was thinking that 2 and 6 injectors were leaking but they weren't. Did injector balance test and coil test. A little hard doing the balance test but they all drop the same. Ohms on the coils were in specs. Can anyone help me with this problem? Thank you

 

Hey I'm wondering dose this truck have an extended crank? This sounds like an internal fuel leak, I would start by carefully removing the pressure regulator and inspecting the 2 o-rings one really small one is more likely the one that you are concerned with. When removed check for any indication that the o-ring was pinched, I recommend using some thing like trans gel or vaseline to lube the o-rings. I suspect that you were on the right track w/reg or pump because that is usually the only things that usually cases this concern. If you wanted to test first i would install fuel line shut off valves in both lines and then get some one to turn the key on while you shut the block offs off then monitor your psi if it still drops then you have a condition w/ reg or injectors but if it holds then you have a condition behind you block off valves such as a pump

I hope this helps you out but I seen these o-rings pinched a few times and done it a time or two my self and it will cause you to go bald from scratching your head until you seen it before. WCT

 

Thanks for taking the time to read all of this and answer. Whats an extened crank? I will check that O-ring. Anything else?

 

[wct]

I have a 2001 3500 Silverado with a 6.0. With the engine off and key on the fuel pressure goes up to 60 pounds and drops steady most times to zero. I took off the main feed line and blocked it off. Checked the pressure at the fuel filter ( using adapter in place of filter) and pressure holds fine, 60 plus pounds. I connected the main fuel line back and lifted the fuel rails and injectors off the manifold and turned on the pump with tech 2 and looked for a leaking injector or cracked fuel rail but no visible leaks. I left the injector conectors on while I did this and fuel pressure still drops to zero. Was i supposed to leave the conectors off the injectors? I have 2 fuel gauges and both drop so its not the gauge. I replaced the fuel pump assy and regulater. It misses intermitently but when ot does Cylinder 2, 6 and 8 misses. 2 and 6 really miss most of the time and 8 every once in a while. I was thinking that 2 and 6 injectors were leaking but they weren't. Did injector balance test and coil test. A little hard doing the balance test but they all drop the same. Ohms on the coils were in specs. Can anyone help me with this problem? Thank you

 

Hey I'm wondering dose this truck have an extended crank? This sounds like an internal fuel leak, I would start by carefully removing the pressure regulator and inspecting the 2 o-rings one really small one is more likely the one that you are concerned with. When removed check for any indication that the o-ring was pinched, I recommend using some thing like trans gel or vaseline to lube the o-rings. I suspect that you were on the right track w/reg or pump because that is usually the only things that usually cases this concern. If you wanted to test first i would install fuel line shut off valves in both lines and then get some one to turn the key on while you shut the block offs off then monitor your psi if it still drops then you have a condition w/ reg or injectors but if it holds then you have a condition behind you block off valves such as a pump

I hope this helps you out but I seen these o-rings pinched a few times and done it a time or two my self and it will cause you to go bald from scratching your head until you seen it before. WCT

 

Thanks for taking the time to read all of this and answer. Whats an extened crank? I will check that O-ring. Anything else?

 

 

An extended crank is when you start the engine and it cranks longer than it should say 3-8 seconds before it actually starts

[royg]

sometimes it starts and dies, not all the time but when it happens it's the first start of the day.