Help: 05 lly no rail pressure

[blk smoke lb7]

Hey guys ive got a buddy with an lly,he was driving down the road and the truck just quit.We got it back to my house and the rail was only like 300 psi and there was diesel driping off the passenger side valve cover and exhaust manifold.Changed the cp3 now only holding 280 psi rail and this is a known to be good cp3.Thinking of doing a test with the glow plugs removed to see if i have any injectors stuck,other then that any ideas?

Thanks in advace,Scott

 

[jmaz268]

Scott start pulling the soft lines off and looking at em...betting thats where it is

 

[pizza pig]

Look to see if any of the lines are leaking fuel, theere has to be air entering the system somewhere to only build 230psi

are you referring to the soft return lines? I just had a truck that broke one of the plastic nipples off the clip and was leaking fuel, but it still ran fine and built proper rail pressure.

 

[blk smoke lb7]

Ill check the return lines but that shouldnt keep it from building rail pressue.It may have an injector stuck open and not building pressure just wondering if there is anything else i can check.

 

[JRODS*LB7]

Hey this jussst happened to me ,Pull off the return line on the cp3 and see if the check valve is stuck!It happened to a pump i bought instead of pumping fuel out the outlet it pumped out the return LOL ...Wouldve been great fuel mileage!:thumb::roflmao:

 

[blk smoke lb7]

Hey this jussst happened to me ,Pull off the return line on the cp3 and see if the check valve is stuck!It happened to a pump i bought instead of pumping fuel out the outlet it pumped out the return LOL ...Wouldve been great fuel mileage!:thumb::roflmao:

To have that happen to 2 different pumps would be very odd but i will checkhow will i know if its stuck?

 

[JRODS*LB7]

it will pump fuel out the rubber hose you disconnected. also pull the hard line or Outlet off you are sapposed to get fuel coming out of there not the return line! Your inlet in case u dont know is the one on the side of the reg

 

[05_LLY]

Where was the leaking fuel coming from?

 

[blk smoke lb7]

Thats just it i cant find anything leaking im thinking that it must have blown a high pressure line or something like that and now the ficm wont fire because the rail is to low

 

[PAT]

Hey this jussst happened to me ,Pull off the return line on the cp3 and see if the check valve is stuck!It happened to a pump i bought instead of pumping fuel out the outlet it pumped out the return LOL ...Wouldve been great fuel mileage!:thumb::roflmao:

How would you know of its stuck? Can you see it?

 

[jmaz268]

Scott I was talking the soft lines going to the CP3 from the fuel filter.

 

[blk smoke lb7]

Scott I was talking the soft lines going to the CP3 from the fuel filter.

Oh rite that could be but the lift pump should make them leak all the time but i will check that.I belive its a leak on the high pressure side and thats why i cant find the leak because the ficm doesnt see min pressure it wont activate the injectors to spray.

 

[$chultz38]

Have you changed the rail psi relief valve yet?

 

[jmaz268]

would have to be really loose to not get pressure on crank....

ie...my truck at your house lol.

just start grabbing each line and tighten....not that many.

there isnt much on the pass side.

 

[PAT]

would have to be really loose to not get pressure on crank....

ie...my truck at your house lol.

just start grabbing each line and tighten....not that many.

there isnt much on the pass side.

???????????

 

[Burn Down]

Scott,
If its a leak causing the low pressure you should be able to see it... Maybe try unplugging the FPR and crank it, see if it will build pressure that way.

 

[jmaz268]

???????????

we had some help when doing my HG and studs.....and they forgot to tighten a few HP lines..


:hug:

 

[JRODS*LB7]

How would you know of its stuck? Can you see it?

when you disconnect the return line coming off the pump if fuel in pumping out of there instead of the outlet to the rail then its stuck,all it is from what i was told is a little ball .The reason i know this is because it happened to a pump i bought the guy gave me my money back and when he got home he took it apart and found the ball was stuck:thumb:

 

[blk smoke lb7]

Have you changed the rail psi relief valve yet?

Ok this is what i was looking for also, so the fprv is in the end of the rail?I am not that familiar with the llys the lb7 is differant.Is there anyway to test to see if this is in spec or not?

would have to be really loose to not get pressure on crank....

ie...my truck at your house lol.

just start grabbing each line and tighten....not that many.

there isnt much on the pass side.

There would be fuel pouring out the valley or somewhere,only 280 psi = big hole lol

 

[$chultz38]

Ok this is what i was looking for also, so the fprv is in the end of the rail?I am not that familiar with the llys the lb7 is differant.Is there anyway to test to see if this is in spec or not?

Drivers rail in the back screwed into the end of the rail. Stock valve is 180 aftermarket plug is 45. Everytime I run into this I put the plug in and then make sure the high side isn't returning. I don't know how else to test it. Not sure were the fuel on the pass side would have came from.