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Draw Straw 5 and return fuel problems


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Just got Draw Straw 5 from Vulcan to help with 1/4 tank sucking air problem. I got an upgraded in tank fuel pump module. This kit replaces in tank pump with clip in aluminum fitting and flex hose to top of sending unit. Then it says to replenish fuel back to module I need to use factory outlet (that's not used anyway) as return a quick connect that is 3/8 and new fitting is 3/8 to 1/2 barb. Before I did this my return was going to filler neck. So now that I got it all plumed according to instructions my fuel pressure went up to 22 where before it was 19. The only thing I can think of is restriction in return going from air dog to module, the actual hole in module is just over 1/4 where before it was just dumping it in filler neck with no restriction. Anybody had this problem ? and what did you ended up doing? If I return fuel to filler neck it will defeat the purpose of doing this kit, as Air Dog will suck module dry.

      While doing this I found return line from vp and injectors kinked off, just 8" down from quick connect on module. It was bent to about 45 degree angle. previous owner must off took fuel tank out to put in draw straw that came with air dog and when putting tank in pinched off return line. So I don't think there was much fuel if any returning for a while now. What problems would this cause? Any opinion is appreciated.  

      Also does anybody upsize return lines and fittings from vp and injectors?

 

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My setup is similar to yours. I had the in tank pump nodule. My ADII came with a kit to replace it. My pick up is new and in the module. My return from the pump is connected to the old pickup connection and the return from the engine goes into the fuel basket also. It works very well. Never had any quarter tank issues. Return fuel to the filler neck just goes to the tank. All of my return fuel goes to the basket.

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I don't have the AirDog Pump. Mine is a Raptor 100 with a prefilter in front of the pump, big draw straw and fuel lines.

 

I fixed mine so the return goes into the fill neck since I want draw straw to pick up cooler fuel for the VP.

 

I cut out the intank screens and unsnaped the old draw straw filter out (small plastic cartrige on the bottom) to help more flow into the module.

 

I've only heard of one guy that upsized his main return line,  but, not each line from injectors, just main line.

 

I used to think this was a good idea, but, Mopar Mike says it's of no benefit so I left it alone.

Edited by JAG1
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My setup is similar to yours. I had the in tank pump nodule. My ADII came with a kit to replace it. My pick up is new and in the module. My return from the pump is connected to the old pickup connection and the return from the engine goes into the fuel basket also. It works very well. Never had any quarter tank issues. Return fuel to the filler neck just goes to the tank. All of my return fuel goes to the basket.

So are you returning both return lines to module? original vp and injector return line that t in to one, and the other line from Ad? To clip on 5/16 and 3/8 module fittings? That's what I did and noticed 3-4 psi increas in fuel pressure. So what I'm thinking now is return from AD plumb it in draw straw that is right next to module from previous owner and take some heat to nilon tube and bent it so it goes to module. Then there sould be no restriction and all fuel will go to basket.
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I don't have the AirDog Pump. Mine is a Raptor 100 with a prefilter in front of the pump, big draw straw and fuel lines.

 

I fixed mine so the return goes into the fill neck since I want draw straw to pick up cooler fuel for the VP.

 

I cut out the intank screens and unsnaped the old draw straw filter out (small plastic cartrige on the bottom) to help more flow into the module.

 

I've only heard of one guy that upsized his main return line,  but, not each line from injectors, just main line.

 

I used to think this was a good idea, but, Mopar Mike says it's of no benefit so I left it alone.

Wouldn't returning fuel to filler neck cause not enough fuel in module? My AD returns a lot of fuel and basket is only so big, I would think you'll suck it dry. But maybe without screen it will suck enough fuel from bottom of module. My instruction says not to mess with screen and leave small rubber valve on bottom of module alone, and only drill one 1/2" hole 3" from bottom.
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I don't know for sure except that my tractor had intank screens. They eventually varnished up to where they were clogged.  Adding a prefilter made it so I can change the filter when it needs changing.  I  also wanted screens out for better flow in the module anyhow.

 

I had a problem for awhile where my Raptor was sucking air at 1/4 tank, during turns, stops and strong take offs. I  then discovered my 1/2'' draw straw was short by a couple inches off the bottom of the tank. I've since lenghtened it and don't hear air anymore but won't know for sure till I get the truck out some more test runs.

 

Removing the screens and little cylindrical shaped screen filter (one that unsnaps) helps with getting bigger holes in the bottom of the module.

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Anybody out there uses draw straw 5 with return from air dog going back to fuel module? My question is still the same as soon as I put my return from air dog from filler neck to module my fuel pressure went up 6 psi I took a shim out that I put in before to bump fuel pressure up to 19 or so but now without it I'm at 22, like I mentioned before I think it's because of restricted return. If I take my line of module and put it in bucket I get 15 psi but as soon as I plug it in to module I get 22 psi. So under heavy load or turning up fuel box fuel pressure fluctuates a lot more now, because spring is not shimmed anymore to keep pressure up for previous set up. I think Vulcan needs to look into this, I'm going to call them soon and see what they tell me.

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Ok for those that been reading, I got it figured out. I had to drill another hole in module and return fuel in1/2" fitting, that way there is no restriction. When I did this my pressure came back to 15-16 so I put my shim washer back in return from AD and got right at 20 psi, I'm leaving it there as it seems to drop a little over time. Got a 1/4 tank now and slammed brakes and took of hard and no sucking air. For those of you with niddel valves on fuel guages you might not notice a drop in pressure right of way as niddel valve makes it a slow proces. Try opening your valve more and drive hard and see if you suck some air.

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So are you returning both return lines to module? original vp and injector return line that t in to one, and the other line from Ad? To clip on 5/16 and 3/8 module fittings? That's what I did and noticed 3-4 psi increas in fuel pressure. So what I'm thinking now is return from AD plumb it in draw straw that is right next to module from previous owner and take some heat to nilon tube and bent it so it goes to module. Then there sould be no restriction and all fuel will go to basket.

I had the intank pump which was installed with a new module. t is very much like the Liberty module, might even be the liberty module. The return from the engine stayed connected to the same fitting and the return for the AD connected to the old supply fitting. I had to drill and install a new pick up line for the AD. Sorry for the late response.

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I'm using the old school draw straw outside the basket.

drawstraw-tip.jpg

 

No issues here for the most part. I can drive all the way down to the empty mark with this old school straw.

Just curious, have you tried unscrewing your niddel vale out a few turns when you get low on fuel and stop hard or take off hard? My original straw was pretty much touching bottom of fuel tank maybe 1/4 to3/8 gap tops and I would suck in air at 3rd to 1/4 of tank if i stop fast.
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