99 Silverado, 4.8L, fuel return restriction causing fuel pressure to j

bowtiebandit6319 · February 22, 2015

Hello everyone, i'm new to this forum thing. I'm an ASE certified master technician, GM vehicles and computer/electrical problems are my specialty. I've got what seems to be a restricted fuel return line. With the engine idling, i'm at about 64-65psi at the test port on the fuel rail. When I remove the vacuum line from the regulator, the pressure jumps to about 76-78psi, which told me to put a new regulator on it, so I got a GM one from the dealership. After replacing the regulator, I primed the fuel system and started the engine. As soon as the engine idled down to its normal idle, I heard what sounded like aerated fuel violently bubbling its way thru the return line back into the tank. The vibration can be felt throughout the entire truck, the return line being the source. Also, this truck has had to have a fuel pump replaced every two years, done by the dealership and ACDelco pumps put in every time, fuel filter changed 2 or 3 times a year and all electrical is good. The truck runs great, i'm just trying to figure out what is burning up these pumps. It's funny how the dealership never mentioned anything about this two year interval being a problem, but why would they try and fix something thats making them money? Anyway, that's a whole different story and I could on and on. Has anyone ever run into anything similar to this? Thanks for taking time to read this and thanks in advance for any replies.