Ok, I thought I messed up my LI-HI wiring for my injectors. But after testing the injectors, weve found that the injectors work AND ive got fuel pressure from the pump. However there is no fuel in either the primary or secondary fuel rails. We turned on the fuel pump with no secondaries in the fuel rail and fuel would not pour out of the rail, but would come out of the line going into the regulator. I took off the secondary fuel rail, cleaned it, and blew into the fuel nipple on the FPR but its like its blocked or something. What I need to know is the following:

A: Can I use an N/A fuel rail or FPR on a S4 TII fuel rail without issue?

B: The fuel is supposed to go in the FPR, through the secondary fuel rail, into the primary, and out of the primary correct? Could I have the fuel lines reversed somehow?

 

The fuel pressure regulator is going to be last in your fuel system. If you hooked up the fuel into the FPR you won't get any fuel.



Some people get confused when they drop Jspecs in because the fuel lines are reversed on them. So I can't tell you if you should have the fuel going into the secondaries or primaries. Just look at the position of the FPR.


Pump-----> Fuel Rail----> Fuel Rail ----> FPR (Last) ----> Return line



The Fuel pressure regulator has a vac nipple on it, not to be confused with the Pulsation dampner.

 

The fuel enters the primary rail, from the fuel filter, the pressure regulator is on the end of the secondary rail, near the firewall. A N/A rail will not bolt onto a TII LIM.

 

On mine the fuel enters the secondary rail and the FPR comes out of the primary.

 

I see... so my fuel lines must be reversed.

My FPR is on the secondary fuel rail facing towards the firewall. Fuel was trying to go into the FPR, into the secondary fuel rail, then down to the primary fuel rail. Thanks for the info guys.

 

This is true?

 

When I get home from work I'll see if I can find some pics of when I removed the stock FPR for an Aeromotive unit.




Fuel Pump----> Filter----> Pulsation dampner / Rail ------> Rail / Fuel regulator -----> Return line

 

Yeah my fuel lines were reversed. It runs fine now..

 

Yes is is. On US engines the fuel flows through the primary rail first, and on Japanese engines it flows through the secondary rail first. This means the PD and FPR are in opposite locations.

On any engine, the FPR is alway the last thing before the return line to the tank. If you connect the supply and return lines the wrong way around the FPR will act like a check valve and prevent fuel from flowing.

 

Good to hear!