Anybody tell me what this is and what it does

[wbski007]

This is off my 92 300CE with a 3.0 you know the one not getting gas to the injectors, I sucked on the vacuum line and it doesn't seem to have any resistance, I still haven't checked the fuel pressure yet, I'm waiting for a gauge, but I thought I'd take this off and see if I could see a filter or screen but no go. Another thing I was thinking of trying is blocking off the return line and see if would run that way??

[porkface]

it is a pressure regulator. the line is not vacuum but a vent line to dump fuel in case the diaphram ruptures. blocking the return won't help but dump MORE fuel. good luck, chuck.

[pawoSD]

They can fail. Solution is new one $$$.

[wbski007]

OK thanks, I'm trying to figure out why I have fuel going to the dizzy but non to the injectors?? they say you have to have, 85-90 lbs pressure but then I have one guy saying he's only getting 60 lbs at the dizzy and his car runs fine, I know I'm getting a good amount at the dizzy because after cranking her over a few time and then cracking the line at the dizzy there is alot of pressure, how much I still don't know but it seems to me to be quite a bit, I'm getting a fuel pressure gauge tomorrow and I'll see just how much I'm getting.