OEM and AfterMarket Fuel Pressure Regulator thread

[Torspd]

Latest FPR upgrade. Since this one has dual inlets, I will be able to equally balance the fuel in the rail. So effectively , I will run a line from the pump towards the egine bay. Y-split that line into 2 line. Run those two lines into the fronts of my APR fuel rails. Then have both rails tie into this FPR. Then the single -6AN return back to the tank. That makes a more even balance across the fuel rail pressure, then at one end.

Also, since the APR fuel rail is larger than factory, at an -8AN diameter. This fuel regulator will be able to match that. It has -10AN ORB inlets. I just ordered -8AN to -10 ORB adapter fittings from Aeromotiveinc.com, to make the transition. This FPR was necessary for me due to the larger fuel requirements I will be needing, and that the Tomei one is not large enough to handle that kind of volume. Nor designed to balance both sides.

 

[Whitebeauty]

Very nice.....looks good...

 

[Whitebeauty]

Ok so basically when doing this mod the hose routing is as follows.

The fuel feed line from the fender which should be the forward one goes to the driver side rail.
From the passenger side rail it goes to the input of your regulator.
Then the output of the regulator goes to the return line on the truck.

Thats it.

 

[Gadget]

Inputs, outputs. It is always the simplest things that trip you up.

G

 

[Torspd]

Yup. Lol. When all else fails, read the instructions.

 

[Torspd]

Inlet of Tomei. Out of the passenger side of the fuel rail goes into it here. That fitting is a -6AN to 1/8" PT from Tomei.

Outlet of Tomei FPR. Run the line back to the steel line on the fender where the OEM line used to attach.

What it looks like hooked up.

******Vacuum hose on top port needs to be attached to a source which sees vacuum and boost*******

 

[rexrunner]

 

[Whitebeauty]

******Vacuum hose on top port needs to be attached to a source which sees vacuum and boost*******

Depending on your tune.

 

[Torspd]

Depending on your tune.

That is a 1:1 raising FPR. If you do not attach a vacuum line to it, then you now effectively have expensive large diaphragm static pressure factory FPR.

It will not raise the fuel pressure without that vacuum/boost hose. Simply adjusting the nut to increase the static is still just keeping it a a static fuel pressure. Just higher or lower than where the factory pressure is at 43.5 psi. Otherwise known as your Base Fuel Pressure.

No matter what your tune is like, it will not increase fuel pressure. Only the FPR will, with that vacuum hose. Mechanically

 

[Whitebeauty]

May it be but not for me. Steady 50psi. Is where mine stays.

 

[Torspd]

May it be but not for me. Steady 50psi. Is where mine stays.

That is what I just said. You adjusted your base pressure with the adjustment nut, from the factory static pressure of 43.5 to a new static pressure of 50.

My base pressure was set to 43 psi. When under boost, it would raise up 14.7 more psi, matching how much boost my engine was seeing. So under boost, my fuel pressure would raise to basically 58 psi.

Whereas yours always stays at 50 because it is static.

 

[rexrunner]

The fuel pressure will stay constant but its now fighting another pressure. For ex 50 psi fuel pressure feeding a 10psi boost charge is now 40 psi. The fpr raise the fuel pressure to compensate for this factor. So yes your fuel pressure stays 50 psi but it needs to compensate for the manifold pressure

 

[Torspd]

His isn't attached to anything. I agree with you on that as well, just didn't feel like covering that portion of its operation, at the time.

 

[ToyotaTacoma4Ever]

1)FPR Mod Install

DISCLAIMER: I'm not responsible for any damage to your vehicle for improper installation. This is only used for a GUIDE.

I have a few schematics to help you located the lines and how they all come together.





Depressurize the fuel system. Pop off your fuse box cover and look underneath of it and it should tell you which fuse belongs to the fuel pump. Pop it out then start your engine until it stalls, once it stalls crank it over a bit more to make sure there's no more pressure in the lines.



Once you are sure there's no more pressure, start loosening the 10mm bolts for the OEM fuel regulator. (You may need to disconnect the electrical lines to the injectors and spark plugs for you can move em out of your way to reach the OEM regulator)

WARNING: Some fuel still might spill out, it sure did for me when i broke the line. It wasnt alot thought.



Once you have the screws out you'll need to find/route the rubber return line connected to the steel line. When you find it pop off the plastic connector and then squeeze the two yellow tabs to pop off the plastic hose.





After that, make sure to take the rubber fuel hose out of some holders, pull on it on the side where the regulator is and then simply pull it all out. (Be sure to disconnect the rubber hose connected to your intake before the throttle body)



Then you are now ready to install the aftermarket fuel rail attachment to the fuel rail. Use the same 10mm screws that got pulled out of the OEM regulator

NOTE: Depending where you have placed your regulator and what type of fittings you have it may be easier to hook up the line to the piece before installing for your hand isnt cramped when you try to put your fuel line in! Cut to the specific length you need!





Once that is finished it is time to install the return line that will connect to your regulator. MAKE SURE ITS A 3/8" HOSE. Cut to the specific length you need and slip it on the steel return line. Make sure to go past the two raised edges on the line!



HARD TO SEE BUT THE RUBBER LINE IS CONNECTED!


After that grab two hose clamps and feel for the steel line edge and put one on that edge. Don't put it on the raised edges!

Then the other will be clamped on the bottom after the raised edges!



Once that is done make the rubber fuel line go behind the supercharger OR wherever else you have your regulator placed and let it hang.

Now start placing all your other fittings/gauge that you need on your regulator and place it/mount it where it will go in the engine bay

NOTE: Before actually mounting it it may be easier to let it sit somewhere on the engine so it can be easier to slip the lines on depending on what kind of fittings you have.





To connect the fuel lines:

1)The line coming from the fuel rail goes into the INLET of your regulator
2)The line coming from the steel return line goes to the OUTLET of your regulator



You are now ready for the boost line. i used a 3/16" line to connect from the TRD blower boost port to my fuel regulator.





Once everything is tight and ready to go. Put back your fuse for your fuel pump and start your engine!

NOTE: It might take a bit of cranking since the lines have no fuel, keep cranking until your engine starts!
Once the engine has started. check where your regulator pressure is!! Mine started at 20 psi and that is WAY to low! Set your regulator for it stays at 43.5 PSI at IDLE WITH THE VACUUM HOSE OFF!

Check your lines for any leaks once you set your pressure!

After when your certain of no leaking lines your are now finished and ready to enjoy the benefits of an adjustable fuel regulator!

 

[Torspd]

Good right up mate! Well done. :top:

Quick question, for clarification. Did you set the fuel pressure, with the truck idling, and NO vacuum hose attached first? And that is when you noticed the 20 psi fuel pressure that needed to be adjusted up?

 

[ToyotaTacoma4Ever]

Good right up mate! Well done. :top:

Quick question, for clarification. Did you set the fuel pressure, with the truck idling, and NO vacuum hose attached first? And that is when you noticed the 20 psi fuel pressure that needed to be adjusted up?

it got copied from my build LOL figured this would save some headaches for some of the people who quite doesnt understand it yet

ooooooooo, no i had the vacuum hose on when i did that, that was probably the mistake i did and why im running really rich right now

yeah the truck was at idle and i seen the pressure at 20 psi with the vacuum hose on, im guessing the vacuum hose is not suppose to be on? lol

EDIT:

Just reset my regulator and WOW does my truck ever pull alot harder now!! freaking impressed now lol new afr is around 10.5

 

[butters607]

Bro that is a hell of a write up thanks a million

 

[ToyotaTacoma4Ever]

Bro that is a hell of a write up thanks a million

Thanks! Yeah, figured someone should make this clear with a nice write up lol should take away alot of the confusion

 

[MadToy]

I'm a little confused. Is it recommended to do the OEM FPR Mod with the stock TRD SC, with stock pulley? Or is it only for when you add the smaller pulley? Just had mine installed a couple days ago, and so far underwhelmed :/. And do I still do it after adding the URD Walbro pump kit?

 

[Torspd]

I'm a little confused. Is it recommended to do the OEM FPR Mod with the stock TRD SC, with stock pulley? Or is it only for when you add the smaller pulley? Just had mine installed a couple days ago, and so far underwhelmed :/. And do I still do it after adding the URD Walbro pump kit?

What year is your truck?

Secondly it is not needed for the stock pulley. It itself does not increase power.

IF you have a TRD s/c, '09+, reflash and no intent to wire in an aftermarket ECU, then if you want to add a little more boost without maxing out your injectors, then you need to do the FPR mod. Thus increasing fuel pressure, increasing the effective flow rate of the injectors, and giving you a little more HP potential with the 425's than if they stayed at static pressure.