Hard to start

[mountaindan]

The hole beside the white suction tube is where the fuel returns

[JAG1]

Once draw straw is installed the return is supposed to be moved over or hooked up to what was the original fuel supply port.

 

Edited November 8, 2018 by JAG1

[mountaindan]

The original have been replaced with the drawstraw there are2 returns one is plugged because I have a DDRP fass.  They both return to the top of the tank

I realize the hose is loose,  only to keep rain out

 

[notlimah]

4 hours ago, mountaindan said:

The hole beside the white suction tube is where the fuel returns

 

So this is your fuel return for the FASS unit correct? Not for stock return line from the fuel T and back of the head right?

Edited November 8, 2018 by notlimah

[JAG1]

56 minutes ago, mountaindan said:

The original have been replaced with the drawstraw there are2 returns one is plugged because I have a DDRP fass.  They both return to the top of the tank

I realize the hose is loose,  only to keep rain out

 

Why is the barbed portion of drawstaw fitting looking new (Aluminum like) when the male threaded portion looks old? At any rate, I would replace the top one (fuel supply) with new. It doesn't look like it was installed right (possible too much teflon tape) and the hoses are supposed to be further up the barbed fittings. 

 

I shave off some of those mountain tops on the barbs. They are too tall, too extreme, which then lets me get the hose all the way onto the barbed fitting and make a tight seal using correctly sized ss hose clamps. I never liked those 'himalayan barbs' I call them. 

Mopar1973Man, trying to edit my post here, I know they will get combined is how I added this, but it will not let me edit my own post here.

Just want to say something about replacing the fitting on the drawstraw; Be sure to hold the draw straw head in a bench vise so as to not stress or crack the module plastic.

[mountaindan]

2 hours ago, notlimah said:

 

So this is your fuel return for the FASS unit correct? Not for stock return line from the fuel T and back of the head right?

That is the return from the T fitting my DDRP don't have a return

[Dieselfuture]

1 hour ago, mountaindan said:

That is the return from the T fitting my DDRP don't have a return

I believe there was more than one draw straw types, the one you have is not the one I like sorry to say that. Fuel should be returned as far down as possible not just dump on top. It may have been one of the first drawstraw kits that you have. Whoever thought of that didn't think of diesel fuel that likes to foam up. This is all just my opinion, but I've done a bucket test what I was dumping fuel at the top and it was foaming really bad and if I put the line in fuel then it stops foaming immediately.

[notlimah]

3 hours ago, mountaindan said:

That is the return from the T fitting my DDRP don't have a return

 

Well that’s what I think your problem is. That would also explain why it doesn’t change anything with a full tank of gas.

 

Basically with that hole all the way at the top of the module there’s always a ‘gap’ where fuel isn’t covering that hole and once you’re stopped air seeps back in causing the hard start. If you were able to get a tube to connect that hole and extend it down to the bottom of the basket I believe your issue would be solved.

[JAG1]

43 minutes ago, notlimah said:

 

Well that’s what I think your problem is. That would also explain why it doesn’t change anything with a full tank of gas.

 

Basically with that hole all the way at the top of the module there’s always a ‘gap’ where fuel isn’t covering that hole and once you’re stopped air seeps back in causing the hard start. If you were able to get a tube to connect that hole and extend it down to the bottom of the basket I believe your issue would be solved.

Then how do you explain that I've no problems for 11 years with my return dumping into my fuel fill neck? I can take off the fill cap and see it running in there......

[Tractorman]

1 hour ago, JAG1 said:

Then how do you explain that I've no problems for 11 years with my return dumping into my fuel fill neck? I can take off the fill cap and see it running in there......

 

Fuel dumping into the fuel neck is a long way from the fuel basket.  After the fuel meets and mixes with the fuel in the tank, its velocity is greatly reduced giving the fuel plenty of time for any dissolved air to rise to the top. 

 

Aerated fuel entering the basket right next to the suction could be a problem.

 

- John

[JAG1]

I understand now... I was misunderstanding in thinking that it meant he was loosing prime parked and the line not all the way down into the fuel, i.e. some of the return line draining into the tank and introducing air into the system.

Edited November 9, 2018 by JAG1

[dripley]

2 hours ago, JAG1 said:

Then how do you explain that I've no problems for 11 years with my return dumping into my fuel fill neck? I can take off the fill cap and see it running in there......

The return into the fuel neck is above everything but maybe the cylinder head return line. Thats on level ground though. My thoughts any way.

 Both my return lines go to the basket. Both of them are above the fuel pick up by about 1/3rd tank, IIRC.  On long road trips I run my tank down to 2 or 3 gallons with no cange in performance. So either the AD is removing the air as advertised or the return fuel splashing is not foaming that bad. Now this is in the in tank pump basket and not the stocker. Two differant animals.

[notlimah]

5 hours ago, JAG1 said:

Then how do you explain that I've no problems for 11 years with my return dumping into my fuel fill neck? I can take off the fill cap and see it running in there......

 

I think @dripley hit the nail on the head in that it’s above most everything else but other then that I haven’t got a better explanation and that’s why I said I can only assume it’s his issue. 

 

In my findings it seems that my ‘hard start’ issues only occur when pointed uphill with 1/2 tank of fuel or less and here’s what I think my issue is.

 

This is my fuel module

 

The shortest tube you see hanging down is the return from the head and VP.

 

Heres my depiction of what my tank looks like full on level ground.

 

Here it is full with nose pointed up.

 

Here it is with 1/2 tank of fuel on level ground.

 

And lastly here it is with a 1/2 tank with nose pointed up. 

 

As you can see, all the hoses in all other situations are submerged in fuel except the final one, so my theory is if I were to extend that tube further into the module, my problem should go away. 

 

Back to the OPs issue, it seems since his VP and head return at the very top of the module that he’s experiencing the same issues I am. Granted I have yet to verify my findings due to pure laziness and  it finding an adequate hose to replace my current one with so I’ve just left it be for now.

Edited November 9, 2018 by notlimah

[JAG1]

My flat bed truck has the return only a little above what the fuel module height is since the fill neck is on the outside of flat bed rail. Makes hard to fill. Other standard bed is up higher. 

[Mopar1973Man]

As far as I know, my factory does not have a tube at all on the return side. 

 

That being said never had a hard start problem. I'm not drawing from the sender basket. I am returning the block and overflow of the VP44 to the basket. My AirDog returns to the filler neck. All my return line are NOT submerged. Just to make you think...

[mountaindan]

I appreciate all the replies on this, I won't get to work on it for awhile.  I will relocate my pump to the frame.  Hopefully I can get it back before spring.

[notlimah]

1 hour ago, Mopar1973Man said:

As far as I know, my factory does not have a tube at all on the return side. 

 

That being said never had a hard start problem. I'm not drawing from the sender basket. I am returning the block and overflow of the VP44 to the basket. My AirDog returns to the filler neck. All my return line are NOT submerged. Just to make you think...

 

Like I mentioned, it’s only my theory but it’s the only thing that makes sense for the issues I’m seeing. One of these days I’ll add the longer tube and see if that fixes it or not.

[Mopar1973Man]

Personally, I think you got an air leak up top. Connector tube o-ring or a mis-seated connector tube or injector which allows for it to drain back to the fuel tank. Because parking nose down keep the fuel from running back uphill to the fuel tank. It could be even the return tee on the back of the head doing it too.

[notlimah]

I’ve replaced everything up front and still the only time it’ll happen is when fuel is below 1/2 tank or so pointed uphill.

[JAG1]

Using a pair of vise grips and a piece of leather, I wonder if you could park nose up hill each day and place the vise grip on the rubber fuel line in various places acting as fuel shut off to help narrow down the location of the so called air vent allowing the fuel drain back?

 

Another thought..... check the factory filter cap since I have heard of them getting a crack. It's one of the highest areas of fuel in the system.

Edited November 9, 2018 by JAG1