I'm working on a 08 f350 and had the valve covers off to look for a fuel leak. The complaint was fuel in the oil. It was overfull on oil and the oil smelled like diesel fuel. I must have started it 15 times and it ran great. Today I put it all back together and now it won't run. the scan tool shows desired fuel pressure at 4800+ but shows fuel rail pressure at 168psi. Did the hpfp go out over night. It does have a injector pressure low while cranking code. I also changed the oil and made sure others in the middle of the dip stick bulb. Now it's over full again but doesn't smell like diesel yet.

Today is taken it back apart to double check everything. I can't find nothing wrong that iv touched. It refuses to run. Turns over good. Just won't fire.

Your talking about oil pressure right, not fuel pressure? Doesn't that engine use high pressure oil to build fuel pressure at the injectors like the old 7.3? I am a 7.3 owner and have helped out on a 6.4 a time or 2. I think they have a high pressure oil pump that does the heavy lifting. The IPR (injector pressure regulator)has been known to fail from a leaking o ring. If it was running when you took it apart then my guess is something didn't go back together correctly. Is there oil in the fuel filter? That is a tell tale sign on a 7.3. I go to the Ford Truck Enthusiasts Forum for all my Ford questions. They have never let me down.

Check to make sure you plugged the high pressure pump connector back in. It's the 4 pin connector by the glow plug module

Doublejack
6.4 doesn't use oil pressure to fire the injectors like the 6.0 and 7.3 engines did.

This engine uses a high pressure common rail fuel injection system. More than likely the high pressure fuel pump is at fault. I've seen it several times on the International version of this engine where it caused no starts as well as diesel in the oil. I would verify that it is nothing you touched that caused the no start first. I would say you'll wind up doing the high pressure pump either way to fix the fuel in oil problem.

Did you find the fuel leak you were originally looking for. And what components of the high pressure fuel system did you take loose. If they loose prime, and get air in the lines sometimes 6.4s can be difficult to bleed.

Did you find the fuel leak you were originally looking for. And what components of the high pressure fuel system did you take loose. If they loose prime, and get air in the lines sometimes 6.4s can be difficult to bleed.

monday, i took off the passanger side 4 small lines to the injectors, removed the fuel rail, to replace the rocker arms, due to the clip on the end of them that comes off and ends up in the oil pan. after putting it all back together, except for the valve covers, i started it up and it ran for 15-20 minutes. it ran perfect and nothing was leaking. so i shut it off. came in tuesday and put everything back together, changed the oil, went to fire it up and nothing, just turns over and over. it did fire up once and went to about 2500 rpms, then fell off and died. after that nothing. iv tried purging the fuel cooler, i even removed the fuel filter to see if it is filling up with fuel and it is.

the scanner shows desired fuel pressure at 4400+ when cranking it over, and the fuel rail pressure at 120+psi....i remember when it was running the rail pressure was almost the same, if not more then the desired pressure.

i have tried everything i can think of, even pressed the fuel cut off switch while cranking and nothing... im starting to really think that pump went out without warning. if that is the case, this explains the over fill oil level and the oil smelling like diesel.

yes iv checked that plug 20 times, i was also reading that the harness to the pump can rub and cause problems. i havent removed the turbos yet to check that. but i would think it would throw a code if that was the issue.

Double check your low side fuel pressure at fuel cooler Schrader valve should be 3-8psi. Then if the valve cover is still off have someone crank the engine over and visually inspect for a high pressure fuel leak-suspect frp sensor. If both are OK double check both pcm connectors for possible bent pins. Rarely do I see a pump fail to a spin no start with insufficient frp while cranking unless I have fuel contamination.

If it ran that long after you put it back together Monday and then on Tuesday it would not restart I would also suspect the hp pump. But I would pull that valve cover back off and crank it while watching each connection at those lines and make sure they weren't leaking, any time they are removed they should be replaced. Not that they do but they should. Good luck a small leak on a 6.4 can be a nightmare to find. How many miles had they gone on the oil change when the oil was originally overfilled and diluted appearing

I am not sure on the oil change. I found aluminum pieces in the fuel bowl. Not big pieces but fine shavings. That can't be good.

I've found that the trucks that regin, if they go over 10000 miles between service's they are over full on oil and it seems thin and has a diesel smell. I believe some fuel gets past the rings when the vehicles enters regin and when they go that long you can notice it. Some of the earlier dodges would be so over full after 8000 miles they would start running bad and loose power from windage on the crank and the oil would arriate.

could it b the camshaft sensor happen.ed to fail at the wrong time

camshaft sensor wouldnt cause the fuel rail pressure to be low. desired fuel rail pressure was 4500 +/- psi, and the rail pressure was 125psi while cranking.

the scanner showed the crank and cam sensors to be in sync while cranking.

the new pump and injectors are in at the dealership, gotta pick them up tomorrow and install them this week. cant wait lol