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low rail pressure

1649 Views 13 Replies 3 Participants Last post by  rs002
i got an 03 with a new motor, injectors, and airdog fuel system. the past two days the truck has been low in power and yesturday it started dyin bouyt evert 15 seconds. i put an edge insight on it and it has low rail pressure. i drove it today and was doin good then the same thang, rail pressure dropped to 2k then died. start it back it would run bout 10 secs and die. got it to oriely changed the fuel filter when i left it would build 11k pressure just pullin outa the driveway it didnt take long for the pressure to start dropping and after about 6 miles it wouldnt build over 5k even at WOT. no codes are present. any ideas would be apreciated.
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the truck has 200k miles on it i just bought it im assuming its the original cp3, idk the exact pressure coming outa the airdog ive gota track down the rite fittings to fit my test guage but i pulled the supply hose from the airdog off the cp3 and turned it on and it had plenty of fuel flow, again i know thats not a concrete test ill try to do a pressure test tomoro
ok ill try that tomoro, when it starts it will read around 5k and after it runs a lil bit it mite get as low as 3k at idle. when it dies itll drop to about 2.5k thats when it cuts out
ok i just did some testing my lift pump is showing 20 psi, i unpluged the fca and started it and rail pressure only went to 15k psi.
idk of nebody that i could swap with and no it is not "making" oil. if nethang it is burning just a lil bit. i thout 5k at idle was the standard. i could be wrong i thout i read that on here somewhere. not saying that i dnt have a problem bc clearly i do. ive got an apointment to ake it to the dealership friday morning.
naw theres no codes and theres rele only one diesel shop in the area that works on pickups and theyve screwed me over before. the dealership im takin it to is in the next county and ive actually heard alota good stuff about them if nothin else ill let them make sure thats wut it is then ill put it in myself.
ive done some research and my truck is not white smoking but my fuel milage has gone down and it does blacksmoke when it wont build pressure. it is not getting fuel in oil. any other signs of injector trouble? i read somewere that to much overflow passed the injector can cause rail pressure to be low how do i check for this? i checked the popoff valve and it had some fuel under the bolt, i dried it and there are no sighns of any more fuel present. took fca off and it rattles so im thinking its good. im starting to learn alot toward a new cp3, and other sugestions
i apreciate the help man. i actually fixed it this morning it was a loose cross over tube. im gona re torque them all tomoro. shes runnin great now. thanks again for the help and im still thinkin bout a new pump
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