Losing Prime

[HammerDown]

UPDATE... Sunday the 19th I installed a new returned line kit.
I started the truck and let it run for several minutes, it's been off until just now, eight days later.
After the GP burn, THANK GOODNESS it fired right up and idled like normal.
Having my truck since new, over the decades, several times I have R&R the return line kit. Every time prior I would see damp or wet O-Rings or the hoses between the injectors and of course the stench of raw fuel... this time I just smelled the raw fuel but never saw the wet area.
The 'only' thing I can surmise is, the rear injector #7 & #8 crossover line was somehow compromised and was the cause of the system losing its prime. I've never had a line fail, only the O-Rings.
Some of the O-Rings seems a little hard and may have become an issue in the near future but again, all those return line caps were dry.

 

[franklin2]

UPDATE... Sunday the 19th I installed a new returned line kit.
I started the truck and let it run for several minutes, it's been off until just now, eight days later.
After the GP burn, THANK GOODNESS it fired right up and idled like normal.
Having my truck since new, over the decades, several times I have R&R the return line kit. Every time prior I would see damp or wet O-Rings or the hoses between the injectors and of course the stench of raw fuel... this time I just smelled the raw fuel but never saw the wet area.
The 'only' thing I can surmise is, the rear injector #7 & #8 crossover line was somehow compromised and was the cause of the system losing its prime. I've never had a line fail, only the O-Rings.
Some of the O-Rings seems a little hard and may have become an issue in the near future but again, all those return line caps were dry.

If this happens again in 2 to 3 years, I would suspect the material the o-rings in the kit are made from. I would then just get the viton o-rings and re-use the caps. You can get fuel hose from Napa if you want to redo that also. I have never bought a "kit" for mine. Mine has the original plastic caps on it that it came from the factory with. They are holding up so far. But like I said in a previous post, I was using hydraulic Buna-N o-rings, they were not lasting past 3 years. I went with the viton from McMaster Carr and it's now been over 10 years on the same o-rings.

 

[rreegg]

UPDATE... Sunday the 19th I installed a new returned line kit.
I started the truck and let it run for several minutes, it's been off until just now, eight days later.
After the GP burn, THANK GOODNESS it fired right up and idled like normal.
Having my truck since new, over the decades, several times I have R&R the return line kit. Every time prior I would see damp or wet O-Rings or the hoses between the injectors and of course the stench of raw fuel... this time I just smelled the raw fuel but never saw the wet area.
The 'only' thing I can surmise is, the rear injector #7 & #8 crossover line was somehow compromised and was the cause of the system losing its prime. I've never had a line fail, only the O-Rings.
Some of the O-Rings seems a little hard and may have become an issue in the near future but again, all those return line caps were dry.

So the issue hasn’t persisted at all since the rebuild? With expansion and contraction due to seasons/temp I can definitely see this being a culprit.

 

[HammerDown]

So the issue hasn’t persisted at all since the rebuild? With expansion and contraction due to seasons/temp I can definitely see this being a culprit.

Well, I only started the truck that one day and it didn't lose it's prime, been sitting again for a few days, I will use it tomorrow.
I've owned my truck since new and honestly, it's time for something new ... I've been searching for a 2025 F150.

 

[HammerDown]

So the issue hasn’t persisted at all since the rebuild? With expansion and contraction due to seasons/temp I can definitely see this being a culprit.

If this happens again in 2 to 3 years, I would suspect the material the o-rings in the kit are made from. I would then just get the viton o-rings and re-use the caps. You can get fuel hose from Napa if you want to redo that also. I have never bought a "kit" for mine. Mine has the original plastic caps on it that it came from the factory with. They are holding up so far. But like I said in a previous post, I was using hydraulic Buna-N o-rings, they were not lasting past 3 years. I went with the viton from McMaster Carr and it's now been over 10 years on the same o-rings.

I looked at the last time I purchased the return line kit from eBay and that was 2018.
However, for some reason I don't believe it's been 7-years since I last replaced the return lines.
Since new I've documented my oil changes, trans service, differential service, water pump, air and fuel filter changes etc and kept receipts BUT > > > I never documented when I changed the return lines, stupid me.
But again, in all the years this is the 'only' time I've lost prime, smelled the raw fuel but 'never' saw the wetness like the few times before... it had me stumped!

 

[HammerDown]

Final update... truck sat another week and fired up.
Sooooo, the moral of my story is: even if you don't see damp/wet return lines but smell raw fuel, change out the return lines and O-rings anyway.