Gas pressure engine off
Thread Starter
Cruising
Joined: Jun 2015
Posts: 10
Likes: 0
Gas pressure engine off
The other day I took the fuel line off the carb on my 74 350 corvette, I noticed that the fuel would not stop no matter what. Not just a splash from removing the line but a total flow vertically from the fuel pump with the engine. I have a sealed gas cap. when I un did it got i got a swoosh and the flow stopped. Wondering if this is normal? Brand new gas tank, sender, roll-over valve, and rubber line. Also charcoal canister is not hooked up how important is that?
Thanks!
Thanks!
Burning Brakes
Joined: Dec 2008
Posts: 971
Likes: 45
From: Middlesex NJ
My 69 has a vented cap (69 did NOT have the EVAP system). Not sure which year started with the NON vented cap but you defeated the EVAP system on your car blocking that off so you now have no vent. That charcoal (emissions) system is to trap the fuel vapors from going to atmosphere and be burned up via the hose that goes to the carb from the canister.
As BASH said ... you need one of them. Simplest at this point is to get a vented cap if blocked the EVAP stuff off at the tank.
I had to defeat the seal/spring in my NEW vented cap (I dont think it was made properly) as it was not venting like it should...I pulled the cap apart and removed the rubber seal (look at my pic... there was no way that cap would vent a reasonable pressure with the way that rubber was being smashed by the spring and valve seat). I would come back from a ride and hear hissing... pulled the cap and it almost blew outa my hand. The tank gets warm from the engine and exhaust heat and the sloshing around builds up vapors.
I have no issues with gas smell or cap leaking. These old vented cars always have some slight gas smell to them but mostly on hot days or right after a ride as the heat bleeds off.
Last edited by mysixtynine; Jun 24, 2015 at 08:46 AM.
