Need a diagnosis

[dracing70]

blocked it? need more advice

well i plugged off the fprv made it look real good just like the diesel bomber forum. took it out for a test and for a milisecond it came alive and rolled some smoke and took off like a bat out of hell. them it went back to how it was. i put it on the scanner and i gained about 1700 to 2000 psi over the other tests but it still wont make the pressure dvt test 23000 desired 14700 is the actual it will spike 19000 for a blink of an eye but only once per test. so is it the pump??? or is there any way around the plug. ?? should i shim and plug or is it impossible to bypass a plugged banjo bolt???? someone help

 

[x MadMAX DIESEL]

If your FPRV is plugged, and you know your lift pump is supplying enough fuel it sounds like your cp3 is dead, or dying

 

[dracing70]

whats the best way to test the lift pump my lb7 has a fass

 

[dracing70]

Is a gauge the only way

 

[McRat]

whats the best way to test the lift pump my lb7 has a fass

Bypass it. Our trucks run great without liftpumps.

 

[dracing70]

yeah thought about that i will try it. Hey pat so if i bypass and it is still actin up does that mean that it is definately the cp3 ?? could there be any electrical components that could cause this and also my friend that i purchased this truck from told me that he ported out one of the fittings in either the rail or the junction block i cant remember . could this cause a loss of pressure due to a volume increase or would that not affect anything??

 

[x MadMAX DIESEL]

Shouldn't. It would take longer to build pressure because of the increased volume, but would still hold the same pressure. But it wouldn't be anything you would notice...

 

[dracing70]

Well to finally put a conclusion on this thread the problem was the cp3 I ended up borrowing a spare it and this was the problem however the spare had a bad regulator and after many hours and three regulators later we got her together. Thank god lol what a difference with max rail pressure

 

[othrgrl]

Can't stress enough how clean you need to be while installing a CP3. You are messing with the fuel lines that are after all filtration has been done. If you get some crap in the supply line you can easily stick a regulator. Get some stuff in the high pressure side and you can tear up injectors.

 

[DIESELJEFF]

im having a very similar issue with an 03 im working on right now. i have plugged the fprv and i command max pressure and it gives it to me. however..... when u are driving the truck it hits 3rd and starts to pull then all of the sudden it wont shift and egts drop and boost drops and it just holds that rpm. if you let off it will shift but then it will do it again in 4th. i logged the truck and it shows a drop of rail pressure from 25,xxx at WOT and then it drops to about 19,xxx and holds. even if you keep your foot to the floor. before it tell this guy that he needs a new cp3, anybody else wanna put in their 2 cents? ALL HELP APPRECIATED!!!! THANKS!!!!!

 

[othrgrl]

Do a bottle test. Is the drop sudden and instant or does it ramp down to 19,000? 19,000 isn't low enough that it should stop all acceleration. Changed the fuel filter(s)? How much pulse are you demanding? Does it have a lift pump?

 

[DIESELJEFF]

havent done a bottle test yet. it happens on any tune i put in it. it even happens when its stock. the psi drop is about 3 seconds long and it continues to accelerate but at the rate of 1 mile per hour per 100 yards. (estimate)

 

[DIESELJEFF]

it has no lift pump and it has new filter