Custom fuel system questions

[Morgan@Midwest Diesel & Auto]

Ok let's start with the factory fuel system. Fuel goes in the fuel bowl from the lift pump, then from there it is routed to the hpfp. The return fuel if then routed from the heads to the intesction where the return from the hpfp meets. They join together and rout to the fuel cooler. From the fuel cooler it the travels back the the fuel bowl. All those ports share common pressure that is regulated at the return outlet where fuel is routed back to tank.

My question is: do you have to have the subsequent 10-15psi on all the returns or can you simply rout them straight to the return to tank.

I would like to do my custom fuel system by regulating the fuel pressure to the hpfp's at 10-15psi. But I would like to keep the returns off the hpfp's and the cylinder heads in a separate circuit that returns to tank unregulated.

I can't see why the returns need 10-15 psi held on them as they should just return back to tank. If there is a good reason you need to have return pressure then I will add another regulator on the return side to hold 10psi on it.

Has anyone done this or have any reason why you can't do that?

 

[blk350on20s]

I am unregulated at the returns. It was fine for a while but i ran into RP issues when i put in the 60s. Im going to put a regulator on the returns to make sure i have no issues.

 

[Morgan@Midwest Diesel & Auto]

Do you think the rp is due to the pump or the unregulated returns? What pump are you running with 60's?

This truck will be running 100% and maybe going to 150% nozzles if I think I can get more out of it.

 

[blk350on20s]

I think it has a small affect but is magnified by a worn pump. Its a stage 1 elite from a while back with around a 100000 on it. ts getting twin pumps right now. Id honestly throw a regulator in. Another safety feature in a way to make sure it has pressure

 

[fordman2121]

I have no return regulator just straight back. The only regulator I have is in the ADII. And I have no fuel bowl. Mines holding pressure just fine but Ive got stock nozzles and not a clue how old the HPFP is, truck has 145000 and Ive only owned for about 8000.

 

[Morgan@Midwest Diesel & Auto]

I just don't see why there needs to be back pressure on the injector returns and the hpfp. Maybe there is a reason but I haven't found one yet.

It would truly make fuel system plumbing a whole lot simpler and cleaner.

 

[blk350on20s]

It honestly wont make it cleaner though. It all has to tie together. Why not tie it together with a regulator. Reason why im going to regulate it is i feel it holds pressure on the return so the hpfp can keep it internally.

 

[B585Ford]

It honestly wont make it cleaner though. It all has to tie together. Why not tie it together with a regulator. Reason why im going to regulate it is i feel it holds pressure on the return so the hpfp can keep it internally.

So based on what you have seen/experienced, is it your opinion that the reason why they are all regulated together is that the HPFP does require "backpressure" to function correctly? Is that is the case, is there a sensor somewhere that makes the HPFP not react like it is suppose to or do you think the HPFP just needs "backpressure" by the way it is was engineered?

 

[blk350on20s]

I dont think theres a sensor in there but there is the internal return. I think by keeping pressure on the return it allows the hpfp to utilize more of it. Not necessarily back feeding but allowing it to use more of the unused fuel that would have free flowed away before. Just my opinion though