I have a 1985 F250 Ext. Cab. 460 with a 4 bbl carb. My wife bought it as a birthday present for $500. The engine was rebuilt with 5,000 miles on it. So the guy we bought it from said it needs a fuel pressure regulator and a battery. He gave me the link for a holley fuel pressure regulator part 12-803. So thats the quick back story. This regulator has one 3/8" in and two 3/8" out. I have 3 lines. 1 from the pump, 1 return and 1 to the carb. The return line and carb line are 1/2". The return line has been pinched so i think they had it setup as a bypass from what I have read. I am trying to figure out the best way to make this work and if I even have the correct part for this situation? Im learning so if I say something incorrectly or dont make since please let me know.

Here is a picture of the hookups.



Thanks

 

My guess is that what is missing is the hot fuel handling system, which isn't a regulator per se. It was used on some 460's due to vapor locking problems, and has a small oriface which returns some fuel to the tank, thereby ensuring there is some flow of cool fuel. So, the Holley unit is not the right part.

But, I'm not a guru and certainly not a 460 guru. We need someone like Dave or Jim to come along as I think either could answer it easily. And, there are others that could as well. If one of them doesn't come along soon I'll PM one of them.

 

Thanks for the reply. I have read about that piece but I cant find exactly what its called or where to buy it. I thought that maybe the regulator was like an upgraded one.

 

Hi Justin!

It is called a vapor separator.
Three were available from Ford.
Red Blue or White dot was code for .045" .060" or .090" return orifice.
The vapor would easily pass through the different size holes, and fuel would pass on to the carb.
With the pump in the tank circulating -relatively- cool fuel through the loop.
.090 was for extreme problems, allowing more constant circulation.

These things had a screen in them that would sometimes get gummed up from stale fuel.

Bill K (subford) has the parts numbers.
IIRC, (Brnfree) another member here, found an aftermarket one manufactured by WIX.

 

That makes sinse from what I have been reading.

I have been reading trying to figure out why he said to get the regulator and I found on holley's website that I may need a regulator if there is a high pressure fuel pump installed. When I was following the gas lines I did see a new pump and I saw the box in the truck. Im going to find out what pump it is so im not giving you half of the information.

I dont know anything about this truck so im trying to do as much research as I can. I appreciate any information people can provide.

Thanks

 

If there is a fuel pump that you can see, and not just the switch valve on the frame rail, you will likely need a return regulator.

'Hot Fuel Handling' relied solely on the in-tank pumps.
With nothing connected it's easy enough to test both volume and pressure.

 

The previous owner had no clue what he was doing either, some people thought it was a filter, a regulator or put there by an act of God. I would replace it, try LMC truck parts, great for restoring the older model's. You can search the bone yards. That engine the 7.5 with the Hot Fuel option, had 2 fuel pumps, one on the engine, mechanical and a low pressure electric in the tank. Nothing ever went wrong with those valves besides getting gummed up, which alittle carb. clean couldn't take care of, the original owner doesn't have the valve? Good luck, I have acouple older ford's with big blocks and will check to see if they have the valve. I will let you know.

 

Reps to you for that, Jim. That helps a lot.

 

I believe it was an actual pump on the frame that I saw. Im going to check today.

The guy that sold it to me bought it from a "kid" to help him out with money. So he knows as much as I do.

I would like to put it back to original but right now its sitting at the guys place and I need to get it going to get it home. I live in town homes and my driveway is too steep and the other parking is parallel.

I will have to search to find a vapor separator so when I can I will change it all back.

Thanks Jim And everyone else for the info.

 

That's not the way I understand the system was setup.

Some 460's had a mechanical fuel pump(plain old style) and did not have this system.

Some 460's had a mechanical fuel pump with the return system. The pump had 3 ports on it.

Some 460's had the fuel pump(s) in the tanks. These were electric of course, I don't ever remember seeing a electric pump working with a mechanical pump. This is usually a bad idea, since if the mechanical pump diaphragm has a failure, the electric pump can fill the engine up with fuel.

I believe the previous owner you bought the truck from was trying to simulate the factory return system with the regulator. In theory this may actually work. It all depends on what pressure the in tank pumps run, and what you set the regulator pressure. If the in tank pumps happen to run 6 psi, and you set the regulator to 4 psi output, then in theory you would get some return action going, especially at idle(when you need it the most).

If someone has mounted a aftermarket frame mounted pump, and it runs a higher pressure, you will probably need the regulator, and it woud work even better, since if it ran a higher pressure you would get more return flow from the regulator.

 

No.
The Hot Fuel system had in-tank pumps only and a switch valve on the frame rail.
Some trucks (like mine) had a mechanical pump on the timing case and no electric pumps whatsoever.

With a little sleuthing you can figure it out.
Is there a pair of relays somewhere near the drivers side hood hinge?
Do you have an inertia switch in the cab, or a second oil pressure switch at the back of the block behind the EGR?

 

I searched up the information subford had posted.
Hope it helps

"The hot fuel system provides for some of the fuel in the supply line to be returned to the fuel tank and thus keeping it cooler and reducing the chance of vapor lock.

The FORD microfiche says:
Name: Valve ASSY. (Fuel Vapor Separator & Fuel Shutoff).

E0TZ9N176-B White Dot .090 Used as a field fix for units experiencing hot fuel problems.
E3TZ9N176-A Red Dot .060 For Fuel Starvation or Power Loss.
E3TZ9N176-B Blue Dot .045 For Fuel Starvation or Power Loss."

 

There is a small black box behind the passenger hood hinge. Not sure if this is the relays you mentioned. I will attach a pic at the bottom.
I dont know what an inertia switch is. There is a black button mounted to my dash beside the steerindsteering column. Not sure what it does yet. Lol
I will have to look for the oil pressure switch.

I got the box I believe to be the fuel pump I saw. Going to get a closer look at the pump to make sure. Its a mr. Gasket #12s. Says its 4-7 psi , 35 gal./hr. This doesnt sound like a high pressure pump? I have to get the information on the carb but if this pressure matches the carb would I even need a pressure regulator?

Im still going to look for the vapor separator. If I can get the truck running good then I can get it home and work on it as time and money allows.

Thanks for looking up that info. That should help in my search.

 

7 Psi is fine for a Holley, maybe too high for an Edelbrock.

The inertia switch (from what I understand) was found either on the passenger side of the transmission hump or the drivers side kick panel.
Should have yellow wires from what I remember of the schematics I've seen.
It has a magnetic ball inside, connecting contacts, that releases on impact.
You need to press a button to reset it.

If you post pics, try and show the wire colors.

 

I will look for that switch.

I forgot to post the pic but I will try to get a better one showing wires.

Now I know its not correct but from what ive read I should be able to run the gas line right into the carb since the psi is good. At least until I can fine a vapor separator and do it right. I should be able to use fittings to connect those two lines. Correct me if im wrong on my thinking.