alright i am done swapping in a different lower millage motor in to my s4 na but it wont start....

first off i was having problems with my injectors leaking due to the top o rings being bad but it would start and run for like 30 seconds then die so replaced those and all the other grommets and pinle caps.

so no more leaking fuel but that due to the fact i cant get fuel to my secondary fuel rail.
i dont know if its just cause the fpr went out on me or if there could be another reason.
but i am getting fuel to the fpr but not threw it.

now question is WTF do i do

 

How are you testing if the secondaries are getting fuel? The secondaries won't come on under 3800 rpm, and should also require a load to be on the engine for that to even happen. So, free reving in neutral should only be using the primaries. Is there some particular drivablity problem you're having?

Also, the path the that fuel takes goes to the FPR last. The order is pulsation damper -> primary rail -> secondary rail -> FPR - > fuel return.

 

depending on how bad the injector leak was, the car shouldn't shut off on you within 30 seconds. after you replaced the orings and etc on your injectors is the car still shutting off? and what rocket said, how do you know you're getting fuel to your secondary rails? have you drove the car on the streets and actually put load on it?

 

well you should get fuel to your secondary rail all the time but your secondarys only turn on after 3800 under a load. i just ended up having a line switched. but now that i get fuel flow in the correct direction it will start but it would hold an idle. you have to keep it above 2200 rpm or it will just die out so.... yeah if its not one thing its another.

 

i need help i have checked all my vacum line and fuel lines like four times over. now i am stumped on what would cause this.

 

Have the injectors even been cleaned? What about the fuel filter, have you ever replaced it? My feeling is that it's probably just a dirty fuel system that's causing your rough idle. If you're still worried there's something wrong with your FPR, pull the vacuum hose while the engine is running. Fuel pressure should increase to ~40 psi, which means the mixture will go very rich & it will probably start to run even worse. But you'll know the FPR is doing its job.

 

Haven't experienced this myself, but it could still be a vac leak through one of your intake manifod gaskets or elsewhere. Can you try the propane test?