fuel return priming system...

[steve phillips]

olives are on the metal lines from lift pump to filter base, from filter base to injection pump, and at return connection on back of engine to line going back to tank. 5 in total https://www.oilburners.net/threads/are-these-olives.81414/#post-966744

 

[Nick_Rego]

where do they go? im pretty green here not sure where to even look on the forums... I searched a bit and didnt see anything about it.

I think I we are talking about two different metal lines. I probably should replace the olives in the two feed lines at the filter housing if any one has part numbers for those that would be cool. anyway i mean is there an o ring or washer or something i can put between the top of the fuel rail and the injector lines? The rails already have factory style o-rings on the injectors im just looking for additional sealing on the tops of the rails seems like theres skme moisture on a few of them. as well as one leaking out the bottom which is probably just the injector o rings not being seated or potentially one got nicked going in.

 

[steve phillips]

if you see evidence of fuel leaking on return caps you have air leaks there also.

 

[steve phillips]

https://www.oilburners.net/threads/zicam-bottle-cap-trick-for-fuel-return-o-rings.84842/

 

[nelstomlinson]

I don't know all the ins and outs of the injection pump, but I believe it has a return line on it, and when the fuel leaks down in the return system, it will drain the injection pump. That is why when you have this problem, the engine will start and run and then stall shortly after. The engine runs on the fuel left in the high pressure injection lines, and then all the air from the injection pump hits and it stalls out.

It's beginning to sound as if a valve in the return line is worth while. It could stick up through the driver's floorboard, open it when you start, close it when you shut down.

The return system on these engines is ridiculously fragile and failure prone. The pencil injectors on my John Deere never give a problem. I wonder if they could somehow be adapted to our engines?

 

[420Bullnose]

I hooked up a Eldbrock electric diesel pump right after the selector valve to PRIME the system. I wired a toggle switch into the cab, so now I just flip a switch and drain the air from the Schrader valve on the filter housing and she starts right up, also if I run out of diesel, all I have to do is crank the engine for 2-4 seconds, flip the switch, hit the Schrader valve again and she starts right up. And if it was an Emergency and my lift pump went out I can limp her home.

 

[franklin2]

It's beginning to sound as if a valve in the return line is worth while. It could stick up through the driver's floorboard, open it when you start, close it when you shut down.

The return system on these engines is ridiculously fragile and failure prone. The pencil injectors on my John Deere never give a problem. I wonder if they could somehow be adapted to our engines?

I had this idea to try and put a electric solenoid valve in the return line, but have never got up the gumption to try it. Really when everything is right you do not need it. But your manual valve idea would be the same concept.

If you want to park your truck with the rearend up a steep hill, that works also. If your John Deere's fuel tank is higher than the rest of the fuel system, that is the reason it doesn't have as many problems. You could put your fuel tank on top of the cab

 

[Macrobb]

You could also just swap to a electric pump. I don't think I've seen anyone do it, but you could put a electric pump between the mechanical lift pump and the filter.

I've done this on one truck; it worked I think... The mechanical pump will push fuel through the electric easily enough.

I don't know all the ins and outs of the injection pump, but I believe it has a return line on it, and when the fuel leaks down in the return system, it will drain the injection pump. That is why when you have this problem, the engine will start and run and then stall shortly after. The engine runs on the fuel left in the high pressure injection lines, and then all the air from the injection pump hits and it stalls out.

No, NO, NO NO.
First off, the fuel in the high pressure lines is 'static' - it doesn't move at all without fuel (in the IP) to push it forward. The IP gets it's 'working' fuel exclusively from the inlet side of the pump; what's in the housing is already "used" and serves no purpose except cooling.
When you have air intrusion, the fuel being run on is the small amount in the hard line from the fuel filter down to the IP. That's it.


Back to the original issue: STOP WORRYING ABOUT THE RETURN LINES. They don't even need to exist for the engine to run(it'll just spray fuel everywhere, especially the IP return).
What you need is simple: for fuel to /not/ drain out of the filter, back down the supply line and out.
If you have a solid, new lift pump - it acts as a check valve and prevents fuel from draining back. As they age, they stop sealing perfectly - good enough to pump fuel, not good enough to prevent a small amount from draining back over hours.

The solutions are:
1. Make everything perfectly sealed - from the top of fuel filter back down to the tank. This would be deleting the return orifice, fixing any little leaks, etc.
2. Install a check valve or electric pump in the supply line to the fuel filter. It won't matter how badly anything else leaks, if the fuel can't flow back down the supply line.

I personally would go with option two more than anything; that way you don't have to delete the return orifice(which helps a lot if you run low or out of fuel - getting air when running).

 

[IDIBRONCO]

If your John Deere's fuel tank is higher than the rest of the fuel system, that is the reason it doesn't have as many problems. You could put your fuel tank on top of the cab

The guy who owned the shop I used to work at also had a scrap iron business. He'd pull his front end loader around behind his 99 F350 CC dually PSD (for the last couple of years that I worked for him). He wanted extra fuel capacity so he mounted the fuel tank from a John Deere in the bed. It used an electric solenoid to cut off the fuel flow (gravity fed) into the stock tank. He kind of combined both of these ideas.

 

[franklin2]

I've done this on one truck; it worked I think... The mechanical pump will push fuel through the electric easily enough.


No, NO, NO NO.
First off, the fuel in the high pressure lines is 'static' - it doesn't move at all without fuel (in the IP) to push it forward. The IP gets it's 'working' fuel exclusively from the inlet side of the pump; what's in the housing is already "used" and serves no purpose except cooling.
When you have air intrusion, the fuel being run on is the small amount in the hard line from the fuel filter down to the IP. That's it.


Back to the original issue: STOP WORRYING ABOUT THE RETURN LINES. They don't even need to exist for the engine to run(it'll just spray fuel everywhere, especially the IP return).
What you need is simple: for fuel to /not/ drain out of the filter, back down the supply line and out.
If you have a solid, new lift pump - it acts as a check valve and prevents fuel from draining back. As they age, they stop sealing perfectly - good enough to pump fuel, not good enough to prevent a small amount from draining back over hours.

The solutions are:
1. Make everything perfectly sealed - from the top of fuel filter back down to the tank. This would be deleting the return orifice, fixing any little leaks, etc.
2. Install a check valve or electric pump in the supply line to the fuel filter. It won't matter how badly anything else leaks, if the fuel can't flow back down the supply line.

I personally would go with option two more than anything; that way you don't have to delete the return orifice(which helps a lot if you run low or out of fuel - getting air when running).

I don't know enough about it to debate it, but I do know if you have leaks in the return system it will cause the engine to start and then stop. That would be the o-rings leaking around the return system on the injectors, and any rubber lines on top of the engine seem to cause it also.

 

[Macrobb]

The guy who owned the shop I used to work at also had a scrap iron business. He'd pull his front end loader around behind his 99 F350 CC dually PSD (for the last couple of years that I worked for him). He wanted extra fuel capacity so he mounted the fuel tank from a John Deere in the bed. It used an electric solenoid to cut off the fuel flow (gravity fed) into the stock tank. He kind of combined both of these ideas.

I don't know enough about it to debate it, but I do know if you have leaks in the return system it will cause the engine to start and then stop. That would be the o-rings leaking around the return system on the injectors, and any rubber lines on top of the engine seem to cause it also.

That's because, as I said(see #1), you've got the ability to drain back fuel due to minor leaks in the rest of the system, as well as a lack of a positive check valve on the supply side. Fix either of these, and you've solved the issue. I prefer just adding a check valve.

 

[Story big blue]

On the fuel filter on top of engine it leaks air around the condition on top and beads back clear sealer spray should fix it

 

[Story big blue]

On the fuel filter on top of engine it leaks air around the condition on top and beads back clear sealer spray should fix it

Around fuel filter housings

 

[nelstomlinson]

your John Deere's fuel tank is higher than the rest of the fuel system, that is the reason it doesn't have as many problems.

That is definitely the case on the Deere. The pencil injectors have a metal return cap that screws onto the injector, with a big, beefy seal that gets compressed. They have never leaked. If they did, I'd still be OK, as you say.

You could put your fuel tank on top of the cab

A buddy's dad had a leaky fuel tank in an old International pickup, so he put an outboard gas can in the bed of his truck and ran a hose over the cab, through a notch he cut in the back of the hood, to the carb. It worked great, until we were bouncing down a dirt road and my buddy wound up sitting on the priming bulb. His bouncing up and down on it flooded the carb!

 

[raydav]

I got rid of the filter on the engine. The pic linked below shows;

Supply pump, vacuum switch from original fuel filter, "faucet", two micron Raycor fuel filter.

Huge improvement. The other filter is for the transmission.

https://photos.app.goo.gl/VAUTizoMXsTb6Lbk7