need help with fuel problem

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Dec 29, 2003 | 07:08 PM

#16

love2fixit

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From: Callahan US

From what I've learned following wires and lines the fuel relay is on or off depending on ,first the ignition is on or off and second if there is oil pressure or not. If everything else is working correctly(fuel pumps, selector switch and valve, and relay)it should work unless there is a blockage.

Dec 29, 2003 | 07:27 PM

#17

Franklin2

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From: Virginia

There where some guys on here before, who said this system helps keep vapor lock to a minimum on the 460 v8's. The fuel pump runs fuel up to that fitting on the carb. If I recall correctly, they said it was like a tee with a certain size hole drilled in it, which let a portion of the fuel go back to the tank, where the fuel could be cooled off and pumped back up front again.

The pressure switch is just a safety item. The relay is there to handle the current draw of the pumps. The pressure switch is not large enough to handle it.

Dec 30, 2003 | 04:40 PM

#18

love2fixit

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From: Callahan US

this is the part that I am refering too. It looks like a metal fuel filter. This is also a regulator for the carb and for the fuel pumps and keeps the pumps from burning up as they can constantly pump fresh fuel and they dont have a pressure shut off switch when they build up pressure. As said there is a screen inside the inlet of this device that will catch every bit of large trash that would get by the sock in the tank. The fuel filter is after this in the inlet on the carb. I have had to clean the screen twice in a year. I am going to install a filter between the tank and this regulator soon. I am surprised that more people havent had this problem with these years Fords with the 460. 83 FARMTRUCK let me know if you have checked this out and what the results were. (curious)

Jan 7, 2012 | 02:32 PM

#19

Nate86_469

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i have the same problem as well i dont have any idea on what to do next. my 86 f250 carb 460 was sitting for 27yrs and when i got i did the standard tune up on it because it ran fine for about a week but then like eveyone else it stated starving for fuel. mine had no filter at all on the fuel line , not a vapor seperator or the little brass looking one in the carb, and my return line was just sitting there not hooked up at all. so i put a filter in the carb, added a vapor seperator witch hooked up the return line and still is doing the same thing. it has enough gas to start and run for about 30sec if i give it a few pumps at the pedal while its turning over then it dies. ive run into a deadend and am stuck now. i would like to check the relay but im not sure if what i see is the relay cause i see the black plastice box thing by the drivers side hood hinge but theres only 1 relay in it and its green and i thought there was supposed to be 2 in there a green 1 and a black 1 (the pump relay), or am i wrong?

Jan 7, 2012 | 08:43 PM

#20

GLR

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From: NY and VA

The OPressure switch is located back of the engine with a tee for the oil pressure sending unit. If you jump the wires the fuel pump will run all the time.

Jan 7, 2012 | 08:50 PM

#21

Franklin2

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From: Virginia

Quote:

Originally Posted by GLR

The OPressure switch is located back of the engine with a tee for the oil pressure sending unit. If you jump the wires the fuel pump will run all the time.

As you can see from the diagram, the oil pressure switch only has power in start or run, so the fuel pump will not run all the time if you jump the oil pressure switch.

Jan 7, 2012 | 09:00 PM

#22

GLR

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From: NY and VA

Quote:

Originally Posted by Franklin2

As you can see from the diagram, the oil pressure switch only has power in start or run, so the fuel pump will not run all the time if you jump the oil pressure switch.

Opps forgot to mention that

This whole trouble shooting was explained on a post in the 87 forums. Went trough this problem with my 87. Thought about hooking up an extra switch for a theft deterrent .

Jan 8, 2012 | 06:04 PM

#23

Nate86_469

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ok so i was trying to start the truck and i think i tried to many times cause it now wont turnover at all it seems like the battery is dead but i checked it and its good and i tried jumping it and that dont work and when i turn the key now it sounds like the battery is being drained also when i turn the key all the lights dim to almost off. what could this be now? also i dont know what to do about the fuel problem. its like the fuel pumps are pumping enough fuel to start it but soon as it starts and the pump switches power sources it dies. im not super mechanic so i have a hard time trying to understand the schematics on here can anyone help me? i dont know what to do now.