New return style fuel regulator

[Malicious]

Hi all just put in a return style fuel regulator, I was jut looking to get a few things done to get some better efficiencies and drivability, and I hit a few concerns.

I'm running this style of regulator: with a direct gauge mounted in the regulator
https://www.summitracing.com/int/parts/edl-174133

First up, adjusting the upper bolt did nothing to the fuel pressure. On start up and cold cycle it stayed around 8.5-9psi then after it heated up it was around 6.5psi.

I'm running a mechanical fuel pump, hemi style unit.

the regulator is meant to be 5-10psi, so it should adjust, is it buggered, or am I doing something wrong?

OR a thought, is the mechanical pump just not powerful enough to warrant the regulator?

 

[texas69bee]

I wouldn't think you would even need the regulator. Most of those pumps are running 5.5-8.

 

[snakeoil24]

No regulator required. But if your using a return line to prevent vapor lock then you may have too small of a return line.

 

[Malicious]

yeah I didn't think I strictly needed one, but I did want to have consistency in fuel delivery, return line for vapor lock potential and allow me to swap over to an electric fuel pump easily in the future.

Still seams odd that I can't adjust the pressue of the output even though it is right in the regulators 'meat'.

one other thing I did notice,when I removed the return line on teh fuel sender it poured fuel. So I attached the return line quickly and moved on. is it possible that, that might be an issue?

On the fuel lines, I have 3/8 in and out for the set up. the sender is a 3/8-5/16 unit off the top of my head. so there is a small bottle neck at the sender for the return line (5/16), but I'm not pushing copious amounts of fuel so I don't image that being a problem.

 

[snakeoil24]

Return line needs pressure drop, accomplished by dropping to a larger size return line. If you decide to go eletric use it to prime mechanical and fill bowls. Then shut off. If diaphram blows on mechanical it will flood crank case with raw fuel. So my suggestion is prime with electric start and shut off. Rely on mechanical.

 

[AMX364]

The factory went to a fuel filter with 3 lines the third line was a return using a 1/4 inch return line. This was there answer for vapor lock. For some people have used a "Holley jet" in the 1/4 inch rubber return line to adjust the flow going back to the tank. Your adjustable fuel pressure unit is not working. If the gauge reading is 8.5-9 then SOME carburetors do not like this much pressure.
edit:IMHO

 

[snakeoil24]

The 1/4 return line went thru an expansion chamber "filter" that is why they could use a 1/4 line.

 

[Malicious]

The 1/4 return line went thru an expansion chamber "filter" that is why they could use a 1/4 line.

Was this 'expansion chamber filter' internal or external to the fuel tank?

Seems odd that I would be the only one that this is causing an issue to tho. I doubt many people on here with a return line would be using a custom fuel sender to suit a larger return line. I've also always used a smaller return line on all my EFI builds, not just for sh!ts'n'giggles but under advice from my tuner. These were high HP turbo builds too, pushing more power than my coronet does. My last build used -10 / -8 lines.

 

[snakeoil24]

Do you have any kinks in the return line??

 

[snakeoil24]

Was this 'expansion chamber filter' internal or external to the fuel tank?

Seems odd that I would be the only one that this is causing an issue to tho. I doubt many people on here with a return line would be using a custom fuel sender to suit a larger return line. I've also always used a smaller return line on all my EFI builds, not just for sh!ts'n'giggles but under advice from my tuner. These were high HP turbo builds too, pushing more power than my coronet does. My last build used -10 / -8 lines.

external by the mechanical pump with 2 ports on one side and third on opposite looks like a large in line filter.

 

[Malicious]

I'll re-check the return line tonight, but I highly doubt it as I ran the same path as my feed line except for the hard line through the engine bay. I did have full coming out of the return line port when I first hooked up the return line, as I mentioned earlier. I'd assumed that it was from a full tank - and the returning fuel pressure would over come any resistance. Could this be part of the issue?

 

[Malicious]

I could build a small 1-200ml expansion tank in to the return line just after the regulator... prefer not to tho.

I was just thinking then of disconnecting the return line and running the engine to if there was any flow coming from it. obviously with precautions, line to a bucket a safe distance away etc.

 

[snakeoil24]

external by the mechanical pump with 2 ports on one side and third on opposite looks like a large in line filter.

Fuel Injection is in a different world. These old Dodges run 8 psi or less when your using 45-60 psi changes all the rules

 

[AMX364]

'expansion chamber filter' is referred in the design of the fuel filters in that era(mid 70's to 80's). In the old days you could not buy a non-stock fuel sender other then factory stock 3/8 senders. It is not hard to solder a sender tube to increase the size or solder a return hose to a working sender. On the bench of course.

Lets get back on track, do you still have high fuel pressure? Is it possible that the pressure gauge is connected to the return location? If you bypassed the "new pressure regulator" does the problems go away?

 

[Bigal75]

Return line restriction is causing your issue.