Losing Prime

[franklin2]

Since it's starting and running for a few seconds and then stalling, that means the IP still has fuel in it. When that little bit runs out it stalls as the IP is hit with air from the rest of the empty fuel system.

Do you have a hill in your yard somewhere? Till you get it figured out, you can back the rearend of the truck up high on a hill and leave it parked like that. You can see if that helps the problem and makes it easier on your starter. It won't help the leak, but possibly it might make it show up better.

 

[HammerDown]

Since it's starting and running for a few seconds and then stalling, that means the IP still has fuel in it. When that little bit runs out it stalls as the IP is hit with air from the rest of the empty fuel system.

Do you have a hill in your yard somewhere? Till you get it figured out, you can back the rearend of the truck up high on a hill and leave it parked like that. You can see if that helps the problem and makes it easier on your starter. It won't help the leak, but possibly it might make it show up better.

I do have a sloped parking area and have parked different ways, after several days of sitting the same thing happens.
The valley pan was wet but also oily from under the air cleaner.
I sprayed Brake-Clean and cleaned the valley pan also put a few heavy napkins under the IP to see if any fuel leak could be seen... so far, nothing has shown up. Colder weather set in which 'may' show shrunken Oilives or maybe something in a return line O-ring etc.
I sure hope it's not a seal in the IP.
For inspection I may be forced to remove the rear crossover return fuel line. But my entire return line kit isn't but a few years old.

 

[franklin2]

What o-rings did your kit contain? I was using Buna-N hydraulic style o-rings, and they would only last a coupe of years before they started seeping. I went with the Viton from McMaster Carr and they have lasted so far many years. But I will tell you, when the other o-rings started giving problems, I could see dampness around the return fitting. If you clean everything off with brake cleaner, and then see any dampness around any fitting, that is your leak. It doesn't have to be dripping or a liquid leak.

 

[HammerDown]

What o-rings did your kit contain? I was using Buna-N hydraulic style o-rings, and they would only last a coupe of years before they started seeping. I went with the Viton from McMaster Carr and they have lasted so far many years. But I will tell you, when the other o-rings started giving problems, I could see dampness around the return fitting. If you clean everything off with brake cleaner, and then see any dampness around any fitting, that is your leak. It doesn't have to be dripping or a liquid leak.

As mentioned prior... having my truck since 'new' I've dealt with the usual 'return-line' issues. I've seen them being 'damp' to being 'wet'!
This time I'm just not seeing anything but, I smell the stench of raw fuel.
The return kit I get is 'supposedly' using quality German fuel hose, caps and O-Rings.
A link to what I've used, https://www.ebay.com/itm/273328228626

 

[reset2]

As mentioned prior... having my truck since 'new' I've dealt with the usual 'return-line' issues. I've seen them being 'damp' to being 'wet'!
This time I'm just not seeing anything but, I smell the stench of raw fuel.
The return kit I get is 'supposedly' using quality German fuel hose, caps and O-Rings.
A link to what I've used, https://www.ebay.com/itm/273328228626

I have a truck in need of a head gasket so I can't drive it, I just move it around the house every month or two. Last time I removed the bleeder Schrader valve and pulled a vacuum with a hand pump. Started fine, not practical. Anyway if there is a strong smell it must be dripping on the hot engine somewhere.

 

[HammerDown]

I have a truck in need of a head gasket so I can't drive it, I just move it around the house every month or two. Last time I removed the bleeder Schrader valve and pulled a vacuum with a hand pump. Started fine, not practical. Anyway if there is a strong smell it must be dripping on the hot engine somewhere.

So yours also loses its prime?
I seem to smell the raw fuel more so on the drivers side vs the passenger however, maybe that's just because that's the side I use most.
I have a spare return kit in stock... guess I'll just install it and hope for the best.

 

[HammerDown]

What o-rings did your kit contain? I was using Buna-N hydraulic style o-rings, and they would only last a coupe of years before they started seeping. I went with the Viton from McMaster Carr and they have lasted so far many years. But I will tell you, when the other o-rings started giving problems, I could see dampness around the return fitting. If you clean everything off with brake cleaner, and then see any dampness around any fitting, that is your leak. It doesn't have to be dripping or a liquid leak.

This kit I've used and turns out I also have one in stock.
https://www.ebay.com/itm/273328228626

 

[rreegg]

does the dash fuel gauge operate as expected?

 

[onetonjohn]

I had several leaks (I think). To fix the last one, I pulled the hose/plastic return line, replaced the hose, and put 2 hose clamps on the plastic hose junction. By the time I got here, I had done return line kit, olives, replaced all hoses to water separator, protected hoses from exhaust heat, resealed all plumbing fittings with pipe dope and gas tape. Finally I removed water separator . I spent several sessions re-priming the system after I thought I had it fixed.

That said, last time I took it out, it died when I switched tanks as I was pulling in the driveway. I had found that I loose prime when connected to front take, but it will keep prime when rear tank is selected. I've got a tank selector valve in the shop, but haven't put it in yet. Guess I'm not quite done yet.

 

[HammerDown]

does the dash fuel gauge operate as expected?

Negative, the sending units failed a while back and when I dropped both tanks because the OE shower heads broke-off the 'sending units' weren't available for my truck... I believe they now are?
Thankfully the fuel tank selector switch still operates.
Again, zero fuel leaks under the truck.

 

[HammerDown]

Well... I just finished installing a new return line kit... fingers crossed cause I need a break.
The 'only' questionable line was 'maybe' the rear crossover for injectors #7 & #8.
But again, with the raw fuel I was smelling it should have left a telltale.

 

[Old Goat]

Ford F-Series Pickup Gas Tank Sending Units

<p>Keep your Ford truck’s fuel gauge functioning properly with quality <strong>fuel tank sending units for F-150, F-250, and F-350 models</strong>. A faulty or worn-out sending unit can cause erratic or inaccurate gauge readings, leaving you guessing on fuel levels. At Gas Tank Depot, we offer...

www.gastankdepot.com

Click on "Fuel accessories" at the top for the "Shower Heads".


Goat

 

[david85]

For what its worth, my truck does get a little temperamental in the first few weeks of winter and I'm pretty sure its an air leak at the injector O-rings. Never leaks down enough to drain the filter and cause a long crank. But it does sputter a little on initial startup, no matter how long I hold the glow plugs on (dual coil plugs, so I can get away with that). If it gets bad enough, I give all the return caps several twists to try and re seat and lubricate the O-rings. Even with Viton, they still get temperamental once in a while when the weather first gets cold. Haven't replaced them for several years and the truck never fails to start.

 

[rreegg]

Have had some issues with extended cranking during cold starts last 6 months or so. Similar to @HammerDown engine will fire off for a couple seconds then die and require extended cranking to start back - then is good. This happens with either tank selected but seems to only occur when parked facing uphill. If parked uphill, restarts are successful for maybe 24-48 hours after parking. When possible I only park facing downhill now.
The front fuel gauge doesn't work and displays constant Empty. Rear gauge is fine. I figure there's some fuel drain back/siphon action related to the shower heads. Rebuilt the fuel return lines around 2021 and no leakage observed there. Been following this thread to see how things turn out

 

[franklin2]

Have had some issues with extended cranking during cold starts last 6 months or so. Similar to @HammerDown engine will fire off for a couple seconds then die and require extended cranking to start back - then is good. This happens with either tank selected but seems to only occur when parked facing uphill. If parked uphill, restarts are successful for maybe 24-48 hours after parking. When possible I only park facing downhill now.
The front fuel gauge doesn't work and displays constant Empty. Rear gauge is fine. I figure there's some fuel drain back/siphon action related to the shower heads. Rebuilt the fuel return lines around 2021 and no leakage observed there. Been following this thread to see how things turn out

There is no way the fuel can drain back from the engine, unless air is coming in at the engine somewhere.

Think of it like a straw that you put into a drink, hold your thumb over the top of the straw, and pull the straw out of the drink. The liquid left in the straw is going to stay there in the straw forever till you take your thumb off the top of the straw and let air in. That is how these truck's work, the fuel system on top of the engine is totally sealed tight, and the fuel cannot make it's way back to the tanks, either through the return or through the fuel pump lines unless air is allowed to enter somewhere on top of the engine.