Lil'John

Title mostly states it all.

But to elaborate, I've got a 2004 LQ4 swapped into an older Land Cruiser. It is a returnless fuel rail style.

Currently, I am using an external fuel pump with a Corvette fuel filter/regulator assembly.

I am having a custom tank made that uses the 4th Gen F-Body LS1 fuel pump. Exactly the same as the attached picture.

So the question is how to I correctly plumb it?

One port has the fuel pump attached to it. One port appears to be a venting port(middle?). Last port appears to be a return.

Should I just run the pump to the Corvette filter, run the return from the Corvette filter to the return port, and then vent the tank through the venting port?

Vetteworks makes it sound like the assembly has its own fuel regulator and thus they do the loop as shown.

I'm hoping to order up some parts so I can bust butt on it this weekend.

got-a-ls1

iTrader: (12)

the regulator is in the bucket. if you look at fbody fuel lines the fuel returns to the tank right after the filter or right before it, cant remember. but basically its just like that setup in the picture but a longer distance and hard steel line. the other port is for the evap system . im not sure what your corvette setup is like but sounds like you have it about right... all you need to do with a stock f-body bucket is do something similar to that picture and just run a single fuel line up to attach to the rail. The regulator in the bucket will take care of pressure and with a 3/8 sized line you should be set.

now if you want to run a external regulator you can take the regulator out of the bucket, but this seems kinda pointless unless you want to make a lot of power as the returnless is simple and only one line to run at any real distance.

Ollie8974

got-als1, is correct the fuel line loops around to the pressure regulator to pressurize the fuel system. The open "T" goes forward to the engine. This is the same system I am using on my 79 TA. I will be using a vacuum referenced regulator on the fuel rail.
The pressure regulator is easily removed. Roll the silver spring clip so the open end is facing up in the photo, then push toward the inside of the module. The regulator can be removed.
the black plastic housing the regulator seats in will stay in the module.
Photo 1 4th Gen. fuel pump module.
Photo 2 Fuel pressure regulator inside module.
Photo 3 Fuel pressure regulator removed.

Lil'John

Thanks for the replies.

Is the internal regulator on the sending unit something that I should be concerned about? Does it fail often?

The LQ4 is basically stock except for center dump Hooker headers, no cats, and a "straight" tube to an intake box. Not much of a tune beyond stock.

got-a-ls1

iTrader: (12)

not at all...

an external regulator is run right after the rails in a high flow fuel system and then returns to the tank... reason being is that a regulator way back in the tank doesnt know the pressure drop at the fuel rails. This is only a problem with a BIG need for fuel for big horsepower. basically a regulator after the fuel rails keeps the pressure in the rails more steady > 600-700 rwhp applications. your fine with the stock regulator. 3/8 line and stock regulator has been taken to 700 rwhp with twin pumps.

yossarian19

I'm not understanding something. You run the feed line to a "t" fitting, one open end to the rail the other to the return. I see that in the picture. How is this pressurizing the rail, though? Wouldn't all the fuel pressure dump into the return & starve the engine?
I'm in the same situation as the OP and would like to pop the regulator out of the stock bucket & use the C5 regulator / filter... thoughts? Or should I just plumb the C5 regulator in, pretending the LS1 assembly doesn't have a regulator? I'll admit I'm slightly attached to making the parts I've already purchased work for me, but really, I just want to get this project done in such a way that I dont' have to trouble shoot later.

Ollie8974

with the above set up, the pump is pushing fuel against the regulator, the fuel system is pressurized all the way to the injectors. No other regulator is needed.