I've just put some 30lb injectors and a regulator in my car and i ran a 4an line as a return to the tank the problem is that i cant lower my fuel pressures more than 35 psi. I even tested it with just the line and with no regulator and it gives 35 psi. I also checked to see if the line was pinched or something but its not. Is a 4an line too little for a fuel return ??? should I put a -6an line?
any suggestions are welcome

TIA

I used the factory supply line as my return and ran a 6an feed, no problems here.

Have you checked the diaphram, mine did that and i replaced it with a new one and it worked fine. What disk are you running?

99 RS-T
"New bottom end(8.6:1 w/long rods)"
Turbonetics 60-1/Portfueler/etc!!!!!

yeah i checked the diaphram and its ok i even put the line directly in the fuel rail to see if it would give me a lower fuel pressure and it didn't. do you think the 4 an line is too little to use it as a return line???

No I am using 4AN for my return. My idle is set a 12psi with 450cc. Are you running a SFMU or what are you using to adjust your idle with.

I had the same problem the -4 line was too smallI had to make a bigger return line -6 and it lowerd my sfmu to almost 15psi at idle

yeah thats what i'm going to do run a 6an line as a return. i guess im gonna have to run rich at idle in the mean time. I already got the CEL for fuel system too rich.

Did you remove the schrader valve in the fuel rail?

of course i removed it that was the first thing i did. I already ordered a 6an line i'll tell you guys if that was the problem.

cool good luck!

well the 6an line fixed all my problems i guess the 4an line is to small for a return line. that 6an line is huge compared to the 4an.
right know i have a static fuel pressure of 25 psi with 30lb injectors and the fuel trims look fine. thanks for the help

Ok i can see the proof is in what hes done there by switching to 4an and everything is fixed.

Can someone shed some light on this, i've already ordered my 4an lines from earls. Should i return them and get 6an, or is this just an isolated incident.

I thought it was send changing to 6an wouldnt make a difference because the test port on the fuel rail is 4an.

*98 eclipse rs
*2005 srt4 (screw the warranty let the modifications begin)