hi
today I install my str fuel rail and the car now is backfiring under 3500 rpms the fuel pressure is set to 45 , the car is not boosted yet but it will be in the next few weeks even at idle the thing sound like if someone was shooting a 38 inside the motor
fuel set up
stock injectors
stock fuel lines
walbro 255 lp/hp fuel pump
str fuel rail
bmn fuel pressure ragulator
my fuel pressure gauge reads around 45 to 48 psi

 

your fuel pressssure sounds ok i would just make sur all the injectors are plugged in and also try and find what cylinder it is coming from just where i would start

 

how would I find from wich cylinder is coming

 

How is the idle?

 

disconnect each injector one at at time the injector that you disconnect and doesnt change the miss is the cylinder with the problem

 

all aof them are missfiring , what I did was change back to the stock fel rail and problem solve lol

 

sounds like the rail/seal are leaking vacuum?? try some new seals maybe?? no experience with the situation but thats what it sounds like to me. do you hear any hissing or anything different under the hood with the STR rail installed? i actually had a leaky injector (vacuum) seal in an sr20det swap that we did, but i cant think if the setups are the same...anyone with experience/input??

 

If you bolted the fpr to the oem port on your STR fuel rail, you need to check to make sure that the fuel port was drilled out in the rail. They come undrilled so that they do not need to be plugged when using an independent fuel pressure regulator.
So basically, you were running the car without a fuel pressure regulator

 

owww I know u mean if there ever was a return port that goes trough the fpr back in to the fuel tank if so yes ther is one drilled hole in there