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Fuel pressure overwhelming carb...

35Remmy

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Floored, I dont know 100%? When i mentioned the issue to my ol man one of the first things he asked was if the return line was too small. His thought is that if the return line is too small, the regulator can only control the PSI so much as the return line itself builds up pressure and cannot dump off enough fuel back to the tank. A bottleneck i guess.
 


RonD

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Rangers used 5/16" lines for either, the out to engine lines used 3/8" connectors
Return 5/16" connectors

High pressure pumps do not have Suction, they need gravity feed
Low pressure pumps use a diaphragm so had suction, which is why mechanical pumps on the engine could suck fuel up and over, and out of the gas tank

The high pressure pump in the frame rail wouldn't work on its own, so a low pressure "lift pump" was need in the gas tank to feed it, and a Reservoir(the canister) to hold siphon when pumps were off

In tank high pressure pumps don't need suction

Low pressure frame mounted electric pumps can work just fine for carbs but they need to be the correct kind, i.e. they SUCK, lol, they need to be able to pull fuel out of the tank, up and over the top of the tank, has to do with pump design

In tank low pressure pump should always be the first choice however, less chance of losing siphon if you ever run out of gas, not a big deal but still a point to be made
 
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35Remmy

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.....It was easy, they said. 😂
 

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Floored, I dont know 100%? When i mentioned the issue to my ol man one of the first things he asked was if the return line was too small. His thought is that if the return line is too small, the regulator can only control the PSI so much as the return line itself builds up pressure and cannot dump off enough fuel back to the tank. A bottleneck i guess.
Did you check for obstruction?
 

35Remmy

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Hi Ron....is there something I am missing??? A 5/16 return line is smaller than a 3/8 supply line. In this case, Im guessing I just have the wrong regulator, them, correct??? I do appreciate the enlightenment. I dont pretend to know what I am doing all of the time. In fact, ai curse myself a lot.
 

35Remmy

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At this point I think I will just call Holley AGAIN (first 2 times, complete @ssholes...in reference to my MSD tach adapter wiring I had to figure out myself bc they were so incompetent....you wouldnt believe the attitudes...probably just disgruntled chevy guys idk)
 

RonD

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Connector is 3/8", line is 5/16" in all the Rangers I have worked on, but my oldest was 1989 so never had a Dual Pump Ranger
 

35Remmy

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I did check for kinks or bends that would inhibit flow...the return line simply runs out of the bottom of the regulator (-6AN fitting/ Ford pushlock adapter...the 5/16 nylon fuel line pressed onto that. (Well, pounded on with rubber mallet and a homemade wooden "vice" placed within my shop vice to hold the line while i pounded and pounded using plenty of assembly lube. Fun.
 

35Remmy

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Ron, ok..i misread...why would the connectors be larger than the supply? Its kind of like this other idea I have had...why would they offer a -6AN to -8AN fitting (my initial thoughts on "rectifying" the possible return line too-small issue, just increase line size to the same diameter as an -8AN)...wouldnt the -6AN just inhibit the flow from the start, rendering an increase to an -8AN impossible??? Sorry for all of these ideas and questions and thoughts and conjectures...
 

35Remmy

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Ron, impressive explanation on high/low pressure pumps...idk why but i only got the 1st paragraph on that lenghthy response you posted. Refreshed and the rest showed up. What would your recommendation be??? I am taking into account everyone elses responses, I dont want to sound like their advice has gone unheard. You freaking guys are a lifesaver
 

RonD

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Ford used different size connectors so people wouldn't/couldn't reverse the lines by mistake
5/16" nylon hose can carry plenty of fuel per hour to an engine


If you have low pressure Lift Pump in the tank now then just use it, remove high pressure pump and put another filter in its place, lol, or ??
You can leave the reservoir(canister) or remove it, your choice, what ever makes the plumbing easier

You can still use your regulator
Return line is not needed


Safety measure if you still have the Fuel pump relay
Get an oil pressure "switch" and add it to the oil pressure sender with a T
Use that switch as the Ground for fuel pump relay
Oil pressure switch closes if oil pressure is above 6psi, and fuel pump would start, in the event of an accident or broken fuel line engine would stall, 0psi oil pressure and fuel pump would shut off

This setup was used for many years when electric fuel pumps were first being used, before fuel injection and computers
Carb has a fuel reserve, the float bowl, so engine can be started before fuel pump is needed
Can't do that setup with fuel injection, need fuel pressure right off the bat
 

35Remmy

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that is the exact pump I am using on my truck. works great. a bit of noise, but no issues. it is wired direct from a cab switch, into an enertia switch. and if i want to kill it i have a ground on off switch also.

As for going mechanical, MAN....id have to change the whole front dress from the heads forward...change water pump, timing cover, fan, etc.


My guess is the off block mechanical pump would NOT fit .... unless you have chopped the frame to pieces and remodeled the steer box into an under frame or some type of magical steering by remote control. lol

cheers
I am running Royal Purple power steering fluid and i bled the shit out of the pump...idk if that would make a difference in noise or if you already did this? I was at WITS END with multiple POS Ford pumps that would NEVER quiet down, no matter what i did. It was futile...i guess that is inherent in a vane-style hydraulic pump. Garbage IMO
 

35Remmy

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Ron, can i ask what you do for a living??? Heh, holy s#it man, you know a lot....I lost my connections when I moved back from FL (FORD COUNTRY)....now in upstate NY...75% GM guys....and no help. Always has greatly interested me in the demographics of brand preferences. I mean, in TX they sell a Ford truck like every 90 seconds or some crazy number like that. Again, I appreciate your advice and everyone elses help here. I guess all i can do at this point is move forward and take chances and see if it works heh.
 

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I think @RonD has photographic memory. Definitely has a good grasp on a variety of subjects...
 

RonD

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I am just old, never made a living as a mechanic but have been a mechanic since my first Erector set, the set with the small screws and nuts you could swallow, lol, gone are the days

And I am old enough to know how little I know, so I thank you and wish it were true :)
 

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