well i replaced fuel filter and that didnt help. so ima try buy some plastic line and put on like you said and see if there is any air in the line. Could it be that the fuel pump is not strong enough for start up? im jus wondering, and you said i should be able to see the fuel pressure with my edge programmer. i still havent seen any function that will show it to me.

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well i just figured out how to use the edge chip and how to use all its gauges. The fuel pressure when its RUNNING is right around 5. but when your turning it over to start it, it is only at 0.6 Does this sound right??

 

are you seeing it in mpa or psi? you need a minimum of 1450 psi or 10 mpa for the ecm to open the injectors.

idle psi should be in the 5K +- some psi range

 

the edge shows it as "Kpsi" so if im looking at it right, its showing the fuel pressure at 600 psi when i try start it and 5000 psi when its idling. Right?? and if it takes 1450 psi to open the injectors then that means i dont have enough pressure when im starting it since im only at 600? right?

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any ideas what to do??

 

other then jumping in and replacing injectors. find someone (dealer) that can command the ecm to provide max psi while idleing. should be able to go to or near 23K psi. then again bad injectors can make this test fail too and then you'll still not know if it is the pump or the injectors. history does say that it will be the injectors though.

if you are tight on money, you could test the injectors return flow rates after removing the valve covers and replace the bad ones. but as they say if one is bad, the rest are right behind it.

looks like it is time to bring it into the dealer or other shop and have them tell you if that is what they think it is. otherwise if it was mine i would replace the injectors myself. try calling Lincoln diesel and tell them you have and see what they think. they also seem to have the best prices around for Bosch re-manufactured injectors.

 

alrighty well i mean if you step on it and get the motor wrapping i think it has great pessure when running. it just dont have enough when cranking it. i was thinkin if i had to replace injectors i would buy some 50 hp or 75 hp ones. whats you input on that?

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also i just recently finally got time to replace a power steering line that had been leaking an i found the metal intercooler line had a hole in it so i replace it to. also changed the engine oil. now when i start it and the let it idle, the edge shows the fuel rail presure fluctuating quite abit. it keeps goin back and forth from like 4600 psi to 7400 psi. does this seem normal? or just another sign the injectors are bad?

 

fluctuating pressure is topically in indication of the pressure regulator valve on the CP3 going bad or some bad tuning. if it is on stock tuning then it is likely the FPR. as a test you can unplug it (it sucks that it is buried deep in the abyss for such a simple test) and this will make the CP3 provide max psi. if it starts fine after that then you may be in luck. replace the regulator.

note: the engine may sound like crap and make knocking sounds when running at max psi while idling, dont worry to much about it, just dont run it for extended amount of time like that.

 

alright ill try that. where is it located at? also, after it warmed up the pressure seemed to stay right around 5000 where its suppose to be. also i forgot to mention that the edge showed it had a code come up, i think it was like U1000. it said it was unknown and i should see manual. any idea what that is?

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well i figured where the regulater was. i unplugged it and it didnt start. the edge showed the pressure at 26000 when tryin to start

 

check out this thread

https://www.dieselbombers.com/chevy-...tructions.html

i believe the "U" codes are loss of serial communication between one of the other controllers. wouldn't worry about it too much unless you are having trouble from it.

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26000! should have started with that. are you sure you didn't just unplug the pressure sensor? if you did then the display would read the max psi in the programming.

 

i think i probably did just unplug the sensor cuz it now has a code come up for high voltage goin to fuel pressure sensor, an thats why the edge showed 26000psi. ima try find the regulator now and unplug it.

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i found the regulator and unplugged it. it still didnt start. the pressure stayed right around 500 psi while cranking it over. once i gave it a lil starting fluid it started and idled rough like you said and the fuel pressure was right around 19000 idling and if i pushed the accelerator down it went to 26000 psi. that hand pump ontop of the fuel filter is always loose and i have to pump it quite a few times for it to get hard but it usually dont stay hard. i doubt that has anything to do with it, im just thinkin bout that and the rubber lines goin to the filter seem really squishy.

 

i think you need to eliminate anything relating to the filter, housing and lines before going any further. some of the old lines have the potential to collapse internally do to being under negative pressure and cause problems. did you ever get around to replacing the out line with a clear one?

attached is a photo showing the approximate location of the pressure sensor and regulator