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.

Hmm that's interesting jag. I wonder if your truck would do the same as mine?

All I know is everything Dodge did to the fuel system was so bad in my opinion that it became my mission to change everything about it.

I.E.

W/S fuel filter before the lift pump

Cut out all fuel canister screens

Eliminate the small cylindrical shaped plastic with screen inside located in the fuel canister.

1/2 inch lines all the way inc. draw straw.

Dump return line to filler neck helping to cool the fuel.

L/P placed down on the frame

1/2 inch shut off ball valves either side of the L/P and pre filter for easy change out not loose prime.

Added my own tank vent so never a vacuum tank collapse from a bad factory tank vent.

 

I know I'm sort of bragging here but I got so pissd about the truck builders always messing things up for the owners of these rigs. I'm very much a rebel. Just like when I bucked High school and took up motorcycling country back roads. Loaded up on some good memories too. 

 

Edited December 6, 20168 yr by JAG1

I hear ya! It's a bit irritating dealing with things that you'd think would be easy decisions to avoid when you're engineering a vehicle!

I'm glad you answered Matt. Was beginning to think I might of hijacked this thread.

 

You know it's all about tight fittings with good easy flow and easy changing filtration system. I don't like the fuel line quick connects after Eric at Vulcan performances' experience with them.

 

I wish I knew what the issue is with your truck Matt. I can only tell you mine is simplified with no Dodge stuff on it. Even half the bottom of my fuel canister is cut away. Nary a problem.

 

That's half my struggle. I don't even know if this will get rid of my issue, or if this is even really an issue to begin with. 

 

If if this were to fix it then great.

 

If it doesn't, then the only other things I can think of that could cause this issue would be my cross over tubes or injectors, but that really doesn't make sense

with this only happening below half tank parked uphill. So we'll see! 

 

 

Matt I think Dripley is correct... I think your short return line is splashing air bubbles into the draw suction. Splash inside the bottom of the canister.

 

Excuse me Bud for sending this thread on a tangent. Matt

Edited December 7, 20168 yr by JAG1

Time to bring back the discussion about your fuel tank access through the bed!

Bed access is a neat idea, sadly it won't work on a short bed!

6 hours ago, JAG1 said:

Matt I think Dripley is correct... I think your short return line is splashing air bubbles into the draw suction. Splash inside the bottom of the canister.

 

Excuse me Bud for sending this thread on a tangent. Matt

 

No worries about thread jacking, it's all relevant anyways! 

 

Only reason for me to not suspect it's a suction side problem is my fuel pressures are solid. Nothing more then 1-2psi fluctuation. If air was getting into that line in sure it's show on the gauge.

 

5 hours ago, joecool911 said:

Time to bring back the discussion about your fuel tank access through the bed!

 

With the amount of time this tanks spent on my garage floor, that idea gets more and more temping! Haha

One of the reasons I don't share what sizes and lengths of steel you need, is because mine is a hash of steel/ aluminum,  was laying around and some is difficult to get, like the flat bed rail pieces. Everything just happened to work out though. Still not easy in the 'how do I fix this major hole' thought process.  Main thing not drill the truck frame but use existing factory holes.

 

Still I think I could come up with a better way of doing it bouncing off what I did originally.

Nice to see you on here Joe.

 

Matt I think you have some tank drainback and a wee bit of air getting sucked into the lines. Especially if you notice immediate hard starts. 

 

Edited December 7, 20168 yr by JAG1

On 12/6/2016 at 8:26 PM, JAG1 said:

Matt I think Dripley is correct... I think your short return line is splashing air bubbles into the draw suction. Splash inside the bottom of the canister.

 

Excuse me Bud for sending this thread on a tangent. Matt

Just to set the record straight, I was thinking more that the return line being above the tank level would allow the fuel to drain out of the return line back into the tank. Therefore allowing air into the high pressure side causing hard starts.

 

You still love me Jag?

 Oh yeah.... I did misinterpret what you said originally. Thought it was about splash/air getting in

 

I don't see how air can get in the high pressure supply side from that unless you know something I don't Dave. isn't there a check valve... something to keep high pressure out of the return?

 

If there is an untightened injector or pressure line. Something is allowing air in to cause minor drain back to the tank.

 

I had it happen when I thought the factory fuel filter cap was tight once. I also found it happened more so when I had a half tank. Later I torqued the cap to factory specs (25 ft. pounds) and problem went away.

Edited December 8, 20168 yr by JAG1

As far as I know there is not a check valve in the oe return line. My thinking is with the return line open in the tank it could allow fuel out of the return and air in and after while it could run all the way back to the head and into the high pressure side just like a leaky tee can do on the return. Since the overflow on the VP has a small bypass it, it could drain the fuel thru that back to the tank. How long it would take I dont know. At least that is my theory anyway, Kinda like opinions, everybody has one.

I see how your looking at it.

 

What I don't understand is when looking at my return flow going down the fill neck, it looks like not much pulsation, more of a passive flow with very little pressure behind it. So there's some way the system keeps the high pressure out of the return flow.  It would be like putting me in charge of a chic filet for the first time  to understand it

Edited December 8, 20168 yr by JAG1

From my understanding of it, there shouldn't be much pressure coming from the VP/injectors. It's really just an overflow of un-used fuel that's making it back to the tank, unpressurized, which would explain why it doesn't pulse and is low flowing. That also explains why when you have a leak at the fuel T or banjo on the back of the head, there are no visible leaks because of the lack of pressure. I'll try and draw up a pic of how I'm imagining it in my head to maybe explain it better.

 

I think me and @dripley are on the same page, but then again, I think that with my wife and I still get yelled at!

Somewhere the cylinder head whatever fuel is not used is returned to the fuel return line and back to the tank. So there has to be a path between the 2. When the engine is shut down all the pressure bleeds off, I figure thats when any air that gets in the head lets the fuel bleed out the overflow hence emptying the high pressure lines. I have no idea how they interconnect in the head. Been googleing with no success so far. 

Kind of figured @IBMobilewould have posted up a picture of chicken showing us how simple this really is.

Lol. There's got to be some kind of way the high pressure is kept out of the return flow. I know you can see minimal pulsation while flowing in the fill neck. So it makes me think there is no way for air to get flowing back up into the fuel needed to run smooth. Maybe mine has an advantage with the termination of the flow being high up in the fill neck since air naturally wants to run upward in liquids. 

 

And if I was building a Chick Filet I'd probably be a cooked goose by the time it was done.

I'm pretty sure there's not a check valve or anything in the OEM return side of things which is why it's so important to have good seals and such. I've read that people have solved OEM return line leaks by adding a check valve, but that was really only a band aid fix.

 

I'll try and draw something up tonight

My thinking is flawed. You are not loosing the fuel thru the head but when the air reaches the return tee it is allow air to move into the return off of the VP. This allows the fuel to drain from the VP thru the bypass in the over flow just like a leaky return tee will do. I think I over thunk myself. 

 

@JAG1 A chicky fil a aint nothing but another building once you learn the chicken ways and build a couple few of them. I am up over 40 some of them. By far the most I have built of anything.

Some kind of Check ball valve...... I don't know.... has to have something when you think how much pressure being generated by the VP.... enough to blow your finger and hands apart and have to be amputated.

 

Dripley is the chicken good enough to go there often for lunch? They got one here in town of Clackamas, Oregon. Have to give it a try.

Edited December 9, 20168 yr by JAG1