Hello. I have a 2004 F350 6.0L I've had since new and have been through some of the standard problems, FICM, a few injectors, blue spring, etc. In the last month have replaced HPOP, oil cooler and EGR cooler after finding a good deal of engine oil in my coolant. Flushed cooling system and replaced with . One issue left that I'm dealing with its air in the fuel line making it look like the fuel is boiling in the secondary fuel filter housing when the pump is running. The truck starts and runs but has no power, probably due to fuel starvation.

Starting at basics, I replaced the O-rings on the secondary filter housing and changed both filters and o-rings, installing the Motorcraft ones I always use, oiling the o-rings before install and draining the water port on the HFCM. The filters are fairly standard maintenance that I've done probably 20 times. After finding that this did not solve my problem I pulled the fuel sending unit from the tank and looked for problems. The tank and sending unit was in great shape, virtually no crap in the tank and nothing clogging the pickup, however I did find some rather deep chafing had occurred on the flexible lines from the tank to the Stainless Steel lines on the frame rail. I'm not certain they had chafed through, but I don't want to risk any future problems so I removed them and will be putting new lines on. The version of the pickup I have does not have the sock or two small filters inside the white box.

This truck is an early 2004 build, build date 7/2003

Questions:

1. What is the best source of replacement fuel lines? OEM or aftermarket? I have been surprised to not really see many options on a search. Where these lines run in a vacuum the connections need to be pretty close to perfect.
2. I have seen discussions about putting a pump in the back either in or beside the fuel tank. I would prefer not to do that if I can avoid it, but will consider it if this is the best long term solution.
3. Please offer any other advise about other places to check for for air leaks.

I do not yet know my fuel pressure. I have a fuel pressure gauge and have ordered the correct fitting I need to connect it. I'm hoping I don't have to replace the HFCM, but will see once I have all the parts I need for the gauge. With this air leak I expect a new pump would make the leak worse than is currently is!!

Thank you.

-Ben

 

I run a FASS 125GPH pump and its 5/8 from the draw tube in tank to the pump itself. Then its 1/2 from pump to the 3/8 tubing where it starts up to the engine by the front tire.

Installed the adjustable regulator up top fuel bowl and run fuel pressure at pump at 75 PSI and regulate it to 55-60 PSI at the engine.


As far as checking for leaks there is fuel line off the draw tube then to frame rail steel tube. Leak has to be between pump and fuel tank. Since that is all drawn to the fuel pump.
Good Luck on the hunt, I would also check the fuel pressure. Stock pumps go 60-80K usually. People are using 6.7 fuel pumps on our 6.0 engines these days.

 

How and when are you seeing air in the secondary bowl?
Do you see air bubbles when cranking OR only when the key is first turned on NOT cranking?

If it's getting bubbles with key on not cranking then the pump is drawing air. Check the HFCM water drain to start. If it's not sealed it can draw in air and it will show in the upper fuel bowl. Also if the line from the tank is leaking it can draw in air. You can disconnect the lines and put in series a piece of clear vynl tubing before and after the pump to see when the air is being introduced, before the HFCM pump or after.



If it's getting bubbles while cranking (no pump) then you may have a bad injector body o-ring or bad injector pintle.