I have a lb7 with 281k on it with all original parts from the day it was new and it has died on my and makes roughly 250psi cranking over. It returns about 150ml to the tank on a 15 second crank period. I have it on a gravity feed system to eliminate air leaks and it'll drain a quart bottle in about 2 hours. I started ripping apart tonight and pulled the rubber line off the cp3 that's kinda in an L shape 3/8 in size and fuel comes out of it. Is it a sign of a failed CP3? Thanks!
Failed CP3?
- Thread starter Desko
- Start date
The vertical fitting is the return fuel and the horizontal is the supply fuel fitting. You have fuel coming out of the vertical fitting with the truck off?
That one will be full of fuel. Should not be under pressure. Your injector return line is plumbed into same part.
Well that rubber line that comes from the pump and up will leak fuel even with the truck not running. Currently the truck wont run at all not even on wd40 if I leave my gravity fed bottle on the inlet line of the cp3 it'll leak it back to the tank from somewhere. It wont anymore because I started to pull it down and disconnected the rubber return line but that line will push alot of fuel out if I squeeze the bottle or it'll be a constant drip. The question is should the pump even drip or return fuel while shut off?
See post 7 and follow the tests procedures how they are laid out...
http://www.duramaxdiesels.com/forum/showthread.php?t=58340
http://www.duramaxdiesels.com/forum/showthread.php?t=58340
See post 7 and follow the tests procedures how they are laid out...
http://www.duramaxdiesels.com/forum/showthread.php?t=58340
http://www.duramaxdiesels.com/forum/showthread.php?t=58340
Your CP3 returned almost 100x the limit. Yes, it is very, very dead. A pump that gone will absolutely not let it start, and will absolutely cause it to die while driving.
With that much return fuel, it probably blew a major internal component all at once. Time for a new one.
When you're trying to pressurize 1000 mL it fuel to 5000 psi 100 mL makes a big difference.
I don't believe 5* should make much of a difference. And with the temp being cooler it would make the fuel thicker so it would probably make your return rates look better then they really where.
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I don't believe 5* should make much of a difference. And with the temp being cooler it would make the fuel thicker so it would probably make your return rates look better then they really where.
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I tested once more with the filter head hooked up this time and ficm unhooked. Injectors returned nothing from what I see and the pump returned a lil over 100ml with the FPR plugged in. So it points to a bad cp3 correct? Or is there anything else I can test?
Maybe I'm confused but your injectors should be returning fuel. Up to 3ml each IIRC.
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They would, if they were getting fed fuel. I think his CP3 is so completely broken they aren't getting any meaningful fuel flow, so nothing to return.
Desko, you've tested a bunch of things, all of which have pointed to a failed CP3. You can keep testing & re-testing forever, but if you want your truck to start again, you're going to need a new CP3.
I plan on getting a sportsman pump for it within the week and machine out the intake horn at my trade school. And yes that what I figured when I wasn't getting fuel from the injectors is that its so shot and the injectors aren't leaking which is a good sign in my eyes. Thank you guys so much for the help!!
well, that has yet to be determined. when you put a new pump on that will actually send fuel and pressure to the injectors, it can show you other issues.
Yes very true but I have faith in my lil ol duramax. They haven't given me issues and no haze or smoking or making oil or cold start issues. I'll test them after I put a pump in it or I'll make a special too so I can put fuel and air pressure to it (50 psi) and see if they're leaking past the returns and put new ones in. All I'm lookin for is 400hp and to pull 12k total weight of cattle over the mountains.
Injectors won't even try and fire until 10 MPa of fuel pressure (1450 PSI), so 50 PSI put in by an air compressor won't tell you anything. Your best bet to test the return rate is to get the new pump in and primed, then do the return rate test with the new pump supplying fuel.
Or just fire it up and see how it runs!
Or just fire it up and see how it runs!
True. It's getting plugged in one last time on Sunday to check out my ficm and stuff to make sure that's good too. I only want to be in there once. Thanks again for your help!
Side note* I know yinz would kill me over it but looking to get a 7.3psd zf6 and make the duramax into a work class puller.
Side note* I know yinz would kill me over it but looking to get a 7.3psd zf6 and make the duramax into a work class puller.