Hey guys, looking to get a new, or at least longer, fuel return line for my fuel module. I installed Vulcan's drawstraw 5 that includes modifying my existing fuel modules so my fuel return from the FASS and VP/INJ all go back into the fuel basket. I had to cut out a couple of the old stock lines to eliminate some unnecessary parts, but now it's extra short and I think may be causing my 'hard start' issue.  

 

Problem is, it seems that when my fuel level gets below a 1/2 tank, I start having issues similar to having a leak in the return line, but I've fixed all those and problem is still there. So this is my last ditch attempt to fix this before I just say screw it and know that if I'm below 1/2 tank parked on a slight up hill for a while that my truck will crank a second or two longer then normal before starting.

You might be on to something. If that return gets uncovered it could let the fuel drain out of it while sitting. Both my returns go back to the fuel canister but i can't for the life of me remember how far down I put them. Must be low because I dont have the hard start issues.

Edited December 5, 20168 yr by dripley

Yea, it's the only thing I can think of that it could be. I've talked with Eric a few times about this and he doesn't seem to think its the issue. He thinks that it would drain fuel back regardless as long as I was pointed uphill. I respectfully disagree to the point that I'll try and install a longer hose and if it doesn't fix it, I'll admit he was right and just live with it haha. 

 

Heres how short mine is and why I think it's causing the problem.

 

 

It's probabaly about 6in above where the suction and return line from the FASS are.

I think you're right, mine goes down all the way maybe 1/4 of bottom. plus if it doesn't then it makes lots of air in that basket if it's not submerged in fuel.

Edited December 5, 20168 yr by Dieselfuture

Yea well whether I'm right or wrong will never come about if I can't find a stinkin' 5/16 flex tube! Any ideas?

I would think any fuel compatible 5/16 hose ought to work. Your just trying to get it to the bottom of basket.

Does it have to be a corrugated line?  Why not any fuel proof hose with a sufficient amount of slack?

Dripley ya beat me to the keyboard.

I thought about that, but my problem with that is finding a fuel hose that's diesel compatible inside and out since this will be completely submerged, I need to make sure the outside doesn't degrade over time. That's why I figured just going with something as close to OEM as possible would be easiest.

 

I ordered up some superflex from Vulcan and I plan on dunking it in some diesel and letting it sit for a while and see how it looks. It's supposed to be compatible inside and out, but I want to double check. I don't need anything coming apart in there, that'd be no good! lol

1 hour ago, Spike48 said:

Does it have to be a corrugated line?  Why not any fuel proof hose with a sufficient amount of slack?

Dripley ya beat me to the keyboard.

it happens to the best of us.

 

1 hour ago, notlimah said:

I thought about that, but my problem with that is finding a fuel hose that's diesel compatible inside and out since this will be completely submerged, I need to make sure the outside doesn't degrade over time. That's why I figured just going with something as close to OEM as possible would be easiest.

 

I ordered up some superflex from Vulcan and I plan on dunking it in some diesel and letting it sit for a while and see how it looks. It's supposed to be compatible inside and out, but I want to double check. I don't need anything coming apart in there, that'd be no good! lol

That might a while, like maybe a long while. any reason not to believe them?

I've let some fuel line that is blue in color on outside and almost look similar to hydraulic hose minus the steel wire inside, made for diesel fuel sit in a jar of diesel for two years and it looked fine. it's not that cheap crap that comes with fuel pumps. 

15 minutes ago, dripley said:

That might a while, like maybe a long while. any reason not to believe them?

 

Not really, but since I'm looking at using the hose in a non-standard way, and in my fuel system, I'm just being extra careful. Eric suggested doing the same as well so that's reason enough to at least see what happens.

 

I plan on leaving them submerged for quite a while, more then a month at least. I don't see dropping the tank to install this anytime soon. At least not until it gets a bit warmer.

 

I'd still prefer to find something OEM style so I'm going to keep an eye out.

2 minutes ago, Dieselfuture said:

I've let some fuel line that is blue in color on outside and almost look similar to hydraulic hose minus the steel wire inside, made for diesel fuel sit in a jar of diesel for two years and it looked fine. it's not that cheap crap that comes with fuel pumps. 

 

Nice! Was it the Parker super flex? At just over 2 bucks a foot, I imagine it's high quality line.

1 minute ago, notlimah said:

 

Not really, but since I'm looking at using the hose in a non-standard way, and in my fuel system, I'm just being extra careful. Eric suggested doing the same as well so that's reason enough to at least see what happens.

 

I plan on leaving them submerged for quite a while, more then a month at least. I don't see dropping the tank to install this anytime soon. At least not until it gets a bit warmer.

 

I'd still prefer to find something OEM style so I'm going to keep an eye out.

My AD came with a piece of flex tube for the fuel pick up. Looks the same as the return but  larger as I remember. Maybe they have some 5/16's. 

I believe it was parker, but can't remember past that, it was quite a bit more expensive then regular diesel line, but it was not a biodiesel line ether, they had to order that one. 

35 minutes ago, dripley said:

My AD came with a piece of flex tube for the fuel pick up. Looks the same as the return but  larger as I remember. Maybe they have some 5/16's. 

 

I asked Eric, he said he didn't have any. He has to buy in bulk, like 15k worth of bulk so sorta hard to get onesie/twosies! Lol

 

24 minutes ago, Dieselfuture said:

I believe it was parker, but can't remember past that, it was quite a bit more expensive then regular diesel line, but it was not a biodiesel line ether, they had to order that one. 

 

Ok, I think it'll be fine but I'm going to do it anyways. This line is biodiesel compatable which apparently is harder on fuel line then straight diesel. I'm a little more concerned about the diesel mixed with opti-lube additives o recently started using.

I don't know you guys... my fuel return looks like this down the filler neck.

Edited December 6, 20168 yr by JAG1

On a CAT site recently there was a CAT service topic that stated that all hard start problems with low fuel in the tank was always air getting into the return line.  Air in the return line will allow the complete fuel system to drain back to the tank. Just passing it on. It made sense to me.

55 minutes ago, JAG1 said:

I don't know you guys... my fuel return looks like this down the filler neck.

 

Jag I'd be willing to bet that's you're return for your lift pump and not the return line from the VP and injectors. Unless of course you're joking!

 

4 minutes ago, oldbeek said:

On a CAT site recently there was a CAT service topic that stated that all hard start problems with low fuel in the tank was always air getting into the return line.  Air in the return line will allow the complete fuel system to drain back to the tank. Just passing it on. It made sense to me.

 

I agree as well. I think us Cummins guys have got that figured out as well! Makes sense that it affects different engines the same. Thanks for passing it along!

Can't you just add a hard line to what you have like dieselfuture did. Look at the photo of his basket

I suppose I could, would just need to figure out what fitting is used on the bottom there. I would prefer a flexible tube though, just so the fuel module wouldn't get held up when it flexes.

I believe it was parker, but can't remember past that, it was quite a bit more expensive then regular diesel line, but it was not a biodiesel line ether, they had to order that one. 

 

That solid half inch aluminum return from lift pump is something I made up with jic fittings and drilled another hole in module. Reason I did this is Factory  restricted fitting made my fuel supply psi swing too much about 3psi or so. after doing this it's been steady + - 1psi no matter what. I had a discussion with Vulcan, telling them to include 2 draw straw fittings and a tube to go down, but apparently they didn't listen. I would have paid extra 40 bucks or whatever save me time running around getting JIC fittings and flareing half inch aluminum tube. Plus going through module I had to figure out a way to seal fuel from coming out of hole, can't quite remember what I did there. but I did  use some J-B Weld compatible with diesel fuel to make that fitting solid with basket. And the little aluminum tube that slips inside corrugated plastic line just fits snug inside, haven't had problems yet. Both aluminum lines have a notch in them, in case they do get in contact with the bottom of basket. I did this with fuel tank installed and more than half tank of fuel so I was able to get lengths cut just right. 

Notlimah, I'm not joking. That's the stock engine fuel return that was going to the fuel tank. I plumbed it there to keep hot fuel from being picked up inside the fuel canister.