O.K. guys, here's one for ya,

86 E350 minnie winnie with a 460, Holley 4180 carb, in tank electric fuel pump. For ever and a day my mom had problems with fuel starvation in this. No one could figure it out. Long story short... I found myself on a trip in the middle of the desert..coughing bla bla bla finally died. I narrowed it down to this fuel return valve (3 way fiitting in the fuel line right before the carb fuel filter). I bypassed it with some spare fuel line I had and plugged off the return line... ran great, got home Ok. What the hell is the purpose other than returning fuel to the tank when the bowls are full? And why do I need that when the float valves shut off the flow anyway? What the hell do I need this $50.00 part for other than to have it stick in the return position and get stranded somewhere ? This part has emmissions written all over it to me. I don't have to smog where I live. I have not checked fuel pump pressure yet although it never starved going up one of the steepest grades in the country (while towing a 2600 lb. trailer) after I bypassed it. Just bought it last week and don't yet have a manual. Can't wait to hear your input. You guys are the source of all Ford knowledge.

 

It's there to keep the electric fuel pump from over pressurizing the carb, and forcing the needle open.....
It is not for emissions purposes. with the return plugged off, you will notice a decrease in mileage, and if you unhook the vacuum canister lines, odds are that you will see gas forced out of the fittings on the carb... Don't ask how I know.

 

I kinda figured that. I need to pressure check my fuel pump cause while I was checking flow from the carb it really didn't seem like I was getting much pressure/flow. Certainly not as much as the mechanical pump on my F250. I'm not sure what the specs are for that electric pump yet. Another thing, while I had the valve off. if I blew through it, ( low pressure) most of the flow came out the return side. I put an air hose to it and with 120 psi the flow came out the carb side. Seems like as pressure builds in the valve it should close the carb side and open the return side. Right?

 

According to Ford it's called a "fuel starvation valve".

 

I cut one of those open on the '84 f-250 that I had... it just had an orface to restrict flow back to the tank- nothing else. I brazed it back together and it's still on the truck.

I had thought that the problem might've been that thing, but it turned out that some rocket scientist had re-wired the fuel pump, and they ran if off the coil wire... so not only was the current running to the pump through the factory resistor wire, but also through the ballast resistor, hence not enough fuel flow.

 

The purpose of that valve is to minimize or eliminate vaporlock. It lets a small metered portion of fuel return to the fuel tanks constantly, eliminating or at least reducing the possibility of vaporlock. It does not have any working parts inside, but there is a small screen that could get plugged and cause a problem. They are less than $10 at any parts store. Hope this clears up any confusion.

 

Yeah, I found that out after talking to a few parts guys. I have a great napa guy. If he can't find it, it doesn't exsist. Been following him since 1984. Seems to me like this part causes more problems than it solves. I bought a new one today. Now why is it I can blow through it and nothing comes out the "to the carb side"? Any more grief and I'm gonna put it out of it's misery.

 

The way mine was put together, you should have air coming out both sides- if you plug off the return side, then can you blow air toward the carb? I reckon it means one of two things- either your '86 return valve is made different from my '84, or something is stopped up. I thought it was a filter at first and never could find one at a parts store... surely a dealer can order one.

 

hell, I say do what I did- hacksaw the damn thing open at the crimped end! If it's stopped up, then you'll know it was the problem- if not, then braze it back together, put it back on and look elsewhere.

 

The part is called the vapor separator.
The dual line set-up is called "Hot fuel handling"
It is designed to keep a supply of cool fuel available at the carburetor by returning fuel heated by high underbody temps back to the fuel tank, thus eliminating vapor lock as beetle pointed out!
The fuel pump produces 4.3 psi.
The vapor separator also reduces pressure to the carburetor by returning fuel to the tank.
If one plugs the return line this will over pressurize the carb needle/ seat assembly and possibly flood the carb.
Also it will deadhead the pump and prematurely wear it out!
Good luck!

 

8 lugs, u are correct sir. Ding, Ding, Ding! We have a winnah! I found that out today at Pearson Ford, from Daniel in parts. However, he told me that it is available in 3 different sizes. .0040, .0060, and .0090. The different sizes are color coded with a dot at the outlet to the carb. The blue dot is .0040, which is what I have...and doesn't work in my vehicle. The service guys put it in when my mother took it in for the same reason at Drew Ford. (They obviously didn't know exactly what was up either.) I know because I just bought a new one (blue dot, same one that Drew put on there)at El Cajon Ford for $46.00 and made it 1 block down the street before comming to a halt. Daniel couldn't tell me the other color codes however.

I ordered a .0090. (Dad always told me "you can never go too big son, especially with a truck". ) The kicker is according to Daniel, the return orifice is what varies in size, not the orifice to the carb, which actually makes no sense as I am starving for fuel. I also cannot find anyone who knows what size came stock with the vehicle to this point. Now if I put the .0090 on and the return orifice is the only one that is larger, ain't I gonna get even less fuel to the carb? I'm hoping he's incorrect and their both larger. I'll visually check it when I go to pick it up. Oh hell let's just throw some parts at it and see what happens. At least I know what the thing is now. Bye the way, I tested my fuel pump volume this a.m. and I'm getting 1 pint in roughly 16 seconds. It's frustrating when even most of the guys at Ford "don't even know what that damn thing is or does".

Thanks guys. I'll keep you in the loop. I'll know if the .0090 works manana.

 

One last thing. I assume I should do a fuel pump pressure check as well? The Chiltons just calls for a volume test only with a single in tank pump.

 

I have had the same problem with this damn thing. Only mine started leaking, and in a fix I replaced it with a fuel pressure regulator. I do not have return line and have been wooried about frying my fuel pumps. I have been running this way for about three years now and for well over 30000 to 40000 miles. I have not have had any problems but it has been bugging the back of my mind. If anyone out there has good reasons why it might be detrimental for me to run this way please share

 

My problem turned out to be the in tank fuel pump. It was an intermittent situation. I unplugged the fuel pump wire from the starter relay and hooked it directly to the battery. The pump started pumping fine for a few minutes and then low and behold it started moaning and groaning and the flow decreased significantly. Replaced the fuel pump, (pain in the ***) and it runs fine. My suggestion is to replace your fuel pump because it's just going to get gradually worse. Also, clean out your fuel tank while your at it. Go back to the .0040" vapor separator valve as well.

 

does anyone have the part # for the fuel pressure regulator / return line or source to purchase one?