Hissing injector after AFPR install

[Legendary]

Me and a buddy installed my AFPR this weekend. Now when I turn the key and the fuel pump comes on there is a quick hiss like air is escaping. No gas is found or smelled. Also the fuel pressure is held any more. It goes up and comes right back down unless I start the car. We did remove the fuel line to install the AFPR and think it might be a cracked o-ring. Could this cause the noise and no pressure?

BTW the car still starts and runs but it hesitates a little.

 

[HISSIN50]

oops, i thought i heard my username.

losing pressure instantly suggests a bad check valve at the pump or bad regulator. having been that you just did the regulator, i would start there.

one can carefully crimp the return line to narrow the cause down.

good luck.

 

[Legendary]

Well the regulator was working good when we took it off another car. I did yank on the injectors to pull the fuel rail up. But like I said. There's no gas leak at all. Just the hiss sound, dropping pressure, and car turns over more before firing up.

 

[ratrapp]

you may have an injector cracked or simply going bad.i had the same problem you do.i thought it was a vacuum leak,i looked all over and sprayed carb cleaner everywhere,no results.while my car was running i had rested my hand on the fuel rail and noticed the noise went away,i started pressing down o n injectors until i found the bad one,it wasn't leaking gas either,just hissing.i upgraded to 24s instead of just replacing one injector.