Well, 87,000 miles and injectors are done!!!!
 

Did a WOT blast couple days ago. Long story short. When the truck is hot, I used to have 6000-7000 psi of rail pressure. Now I am seeing 4800 to 5400. Just that easy. I think I am just going to replace them all and get some upgraded tips.

Did you also check to see if the pressure valve was still holding?

I'd check other things before spending the money on removal and injector tips.

Unless you're just wanting new tips, then go ahead.

I would check torque first on injector tube nuts and limiting valve for leakage first. Run a injector return test, that will tell you if injectors are issue.

This is what I was going to do anyway, it is just speeding up the process. Injector tubes don't losen up overnight.

8 years and 87,000 miles, it wouldn't hurt to check them. Limiting valve is easy to do, and doesn't cost anything. Nozzles won't cause a drop in rail pressure like that. Loosened tubes and or a leaking limiting valve can. Be a drop in mileage to boot.

Took a chance and changed the fuel filters. RP is back to normal. I only showed a 2 psi drop on my fuel pressure gauge. Filters had been on the truck for about 15,000 miles. Go figure.....

Well, not so lucky. Took the truck to dinner tonight and as soon as the truck got to operating temp the RP went low again. Oh well. Looks like I will be calling Tim at TRE back....

Injectors are going out to Don on Monday. Going with Flux 1.6's. I wonder how many injectors have issues...LOL

Sweet!
Post up when you get them back in [guitar]

I'd be willing to bet Don finds excessive leak back in the bodies...

Me too, the question is on how many are leaking.

Do you run pressure boxes (I see Quad X2 which can run pressure)? Have you run some fuel with water in it?

Those are the two most common causes for excessive leak back in shorter mileage injectors that I am aware of.

I have ran pressure rarely on level one with the pressure tune. No water in fuel issues. From what I remember, the 04.5 600 series is more prone to high return. They were the first 600 series engine trucks. We used to see them crapping out a good bit several years ago.....LOL

^^^ part of that early demise had to do with the overall higher pressure the stock tunes were running. They started pressure higher and ramped it faster than 03-04. For example, on my stock tune, I'll idle at 4800-5100 psi; 04.5 and up starts at 6k for idle on a stock tune. That early crapping is what led to the redesign of the bodies.

On the stock tune I can run down the highway at 65 with pressure between 8-9k. Compare that to yours at the same speed and you'll see around 15k on average.