Air in fuel bowl

[crcrawford87]

I've got a 04 6.0 truck in my shop, was towed in because it died on the road. It restarted after charging the batteries and changing out the cheap fuel filters in favor of motorcraft. Truck died after about 5-10 seconds of run time, after that it would only run for a few seconds at a time. Pulled the upper filter and it was full of air, let the bubbles settle and pulled the fuel pump fuse and cranked the engine over with fuel in the bowl-no air bubbles at all. Put the fuse back in and cycle key and lots of air, try cycling the key half a dozen times and pull cap again-still air bubbles. I removed the inlet line into the HFCM and put a 5/16 hose into a jug of clean diesel- still air bubbles-cycle key a few times and same thing. Removed the HFCM and took the cover off to find a lot of crud and corrosion and fuel heater came apart and crap in the pump. Replaced it with an oem unit from ford, still have air bubbles. I put caps on both return lines on the HFCM and put the supply hoses into a jug and I have bubble free fuel! So now I hook the HFCM back to the fuel tank-so far so good no air bubbles besides some very very small ones and they are getting less and less. Hook the supply line back onto the HFCM to the fuel bowl, turn key over- no bubbles. Hooked the return line back up to the tank-all good no bubbles. Hook the return line up from the HFCM to the fuel bowl and I have bubbles again big time. Tomorrow I am going to bypass the section of line between the engine connector near the manifold to the HFCM and see what that does for me. Anybody ever experience this? I thought the return line would leak fuel externally if it had a bad spot in it?

 

[crcrawford87]

I've got a 04 6.0 truck in my shop, was towed in because it died on the road. It restarted after charging the batteries and changing out the cheap fuel filters in favor of motorcraft. Truck died after about 5-10 seconds of run time, after that it would only run for a few seconds at a time. Pulled the upper filter and it was full of air, let the bubbles settle and pulled the fuel pump fuse and cranked the engine over with fuel in the bowl-no air bubbles at all. Put the fuse back in and cycle key and lots of air, try cycling the key half a dozen times and pull cap again-still air bubbles. I removed the inlet line into the HFCM and put a 5/16 hose into a jug of clean diesel- still air bubbles-cycle key a few times and same thing. Removed the HFCM and took the cover off to find a lot of crud and corrosion and fuel heater came apart and crap in the pump. Replaced it with an oem unit from ford, still have air bubbles. I put caps on both return lines on the HFCM and put the supply hoses into a jug and I have bubble free fuel! So now I hook the HFCM back to the fuel tank-so far so good no air bubbles besides some very very small ones and they are getting less and less. Hook the supply line back onto the HFCM to the fuel bowl, turn key over- no bubbles. Hooked the return line back up to the tank-all good no bubbles. Hook the return line up from the HFCM to the fuel bowl and I have bubbles again big time. Tomorrow I am going to bypass the section of line between the engine connector near the manifold to the HFCM and see what that does for me. Anybody ever experience this? I thought the return line would leak fuel externally if it had a bad spot in it?

It was the return fuel line causing the air problem, when the DTRM in the HFCM is open the return line is open to the inlet side of the fuel pump. Got that problem solved and it wouldn't stay running, FICM sounded spotty so I was watching it on the scan tool and this happened.

it's a reman jasper FICM that is 6 months old. Wiring is burned up from what looks like an ether backfire, I'm going to replace the FICM harness. Is the FICM bad also or could the bad wiring be causing this?