[dluns]

Just purchased an 03 3500 2wd NV5600 with 420k miles on it. Probably not the original engine by the way it looks. The previous owner fired the parts cannon at trying to fix a no start issue. The no start issue has been solved but the truck sputters at WOT between 2250 and 2800 RPMS.
List of new parts includes
New ECM (still on stock tuning for now)
New in tank sending unit/lift pump (oreilys)
New stock size injectors and tubes (oreilys)
New fuel filter

The truck runs flawlessly until you get high up in the RPM’s at wide open throttle. Rail pressure moves between 17k and 22k at WOT. I’m watching data on a Edge monitor and it does not have a PID for desired rail pressure. Should I start looking at CP3? Could it be the pressure relief valve in the rail?Looking for some input before I start throwing unnecessary money at this thing.

 

[skeeterpd]

I have very simular prob with 05 , but have not done injectors or lift pump yet, but heading that direction, at wot, mine runs like a scalded dog, but has a "snease" type of mis at medium load, in 2nd, 3rd, 4th, and now 5th and 6th gears. started doing thid with very bad fuel as evidensed by fuel filter debris. have changed filter 3 times in the last 1000 miles, and still get some trash, so its drop the tank time.. I have also changed the cp3 pressure regulator and the common rail pressure limiter, to no avail yet. you say the rail pressure is only 17--22k psi? mine does its thing at the exact same pressures and it..the pressure..take a downward hit along with the 'snease' miss, wi
hite and black smoke out the tail pipe.. lift pressure on mine is 9 at idle, 3-4 while running hard. so far, I am believing the fix is cubic money!! PLEASE let me know what you find fixes things! the wife only allows so much money!!

 

[dluns]

It’s an odd issue, that’s for sure. In my case, if you keep it under 2400 rpms, you’d never know there was an issue. I might try a Fass pump and a rail plug and see what happens. I plan on making this thing a fun driver so those are on the list anyways.

 

[Brethl]

Not sure I would have a lot of confidence in O’Reilly‘s for injectors on a common rail. Maybe check some reviews and see if anyone else has had similar issues?

 

[rghavana]

Yep hopefully new Bosch injectors
pull proper oil sample to rule out internal issue.
perform return testing of CP3,PRV,injectors
Then 03-04 check valve/lash
check compression?

 

[dluns]

Yep hopefully new Bosch injectors
pull proper oil sample to rule out internal issue.
perform return testing of CP3,PRV,injectors
Then 03-04 check valve/lash
check compression?

Highly doubt its a compression issue. Truck has absolutely zero blow by, no fuel in the oil and is not lacking any power. Checking valve lash is on my list of things to do as well but I doubt there far enough off to cause this issue.

 

[dluns]

Not sure I would have a lot of confidence in O’Reilly‘s for injectors on a common rail. Maybe check some reviews and see if anyone else has had similar issues?

I have zero faith in the injectors from oreilys but they were already in the truck when I bought it

 

[skeeterpd]

I agree about bosch injectors as the way to go. but, just one question about 'internal oil' comment; is there any fuel, or oil, additive that will ensure internal oiling, and/or actually clear junk/gunk that may be making one injector stick open? I am thinking along the lines of MMO.

 

[rayvin433]

Hot shots Stiction eliminator. Designed for the 7.3 ford diesel injectors that used oil pressure for actuating the injectors.
Known to help free sticking rings & increasing compression, decreasing oil consumption

 

[dluns]

I’ve been communicating with Todd at TC Diesel with some troubleshooting for the limiting valve (which come to find out has been replaced with a race plug on my truck) and proper cross tube installation and we’ve narrowed the issue down to the injectors and cross tubes being the issue. Going to see if I can get a refund on the junk from Oreilys and get a good set of injectors.

 

[dluns]

After messing with this truck on and off for a couple weeks, I’ve solved my issue. The injectors and the pump were fine. I had a combination of bad fuel and a poorly calibrated TPS sensor. After running the fuel out and refilling with good fuel my stumbling issue went away, but I was still getting odd rail pressures at WOT. Come to find out that the TPS had been replaced but was not calibrated properly. At WOT, the computer was only seeing 73% throttle. Adjusted my sensor and now have full throttle control. Truck runs and drives as it should now. A pump and injectors are still in the plans since this is just a toy but I just wanted to give an update on what fixed my issue.