so, about that slight smell of gas...

[EfiniX]

when I first got my car about... well, whenever ago, I had a pretty heavy smell of gas coming from under the hood on hot days. Turns out that as part of the ongoing hack-job the PO was subjecting the car to, some of the enviro stuff got pulled and I had a line for the fuel tank just sort of... well open. If I had to guess, this was some sort of tank breather line (can't let those hydrocarbons go). EHMotorsports (Evan) plugged it and I've been fine (it didn't run funny or anything, and that's on the old and now new motor).

That being said, i still caught a whiff of gas from time to time. Yesterday, I made a discovery, and I'm wondering if maybe sealing up the system wasn't the best idea (no where for the pressure in the tank to go?).

Here's my observations:

- smells a bit on hot days (just fine this cool morning)
- if I park on a steep slant, with the fuel filler side of the car leaning down the hill (visitor parking spot at my condo) on a medium to full tank on a warm day, I drip gas from somewhere around the tank/fill tube
- my gas cap seals and when I take it off, it can hiss for between 5-10 seconds while the pressure is released

These things seem to point to either a leaking tank and/or an overpressure issue. So is the tank supposed to be 100% sealed, or should I slap a charcoal catch-can on that return line under the hood?

Thoughts? Like I said, the car is running like a top, and I'm the only one noticing the smell. I'm not going to park on that hill anymore, and I've never seen it drip anywhere else (and you can be sure I've looked).

 

[prove_it]

The tank should never be sealed. The carcoal canister (which is commonly removed) is what absorbs the vapors from the tank. During temparture changes the fuel in the tank will emit vapor, as the temp rises, pressure does so too. The canister traps these vapors then while cruising the ecm allows the canister to vent into the intake to burn off the vapors. Allowing the tank to pressurize could result in an explosion (very rare worst case scenerio) or more likely a fuel leak as an old seal fails and then leaks. I don't have a canister, and I left my line open. It's risky, but thousands do it daily without issues. You will be polluting the earth though. Nature will hate you, and probably rain down large hail on your car... /ubbthreads/images/graemlins/smirk.gif

You should at least unplug the line running to the tank to allow it to depressureize. Also the hissing you hear is air running INTO the tank. When you drive the car and fuel is consumed the tank will then become under a vaccum do the the loss of fluid. Not a big issue there, but can cause a tank collape(again worst case scenario).

 

[EHmotorsports]

sounds like you have issues other then just the plugged vapor hose. the inspection cover needs to be removed to see if its leaking around the Fuel pump. then the flex hose needs to be checked from pump to hard metal supply line. also the filler tube hose to tank needs to be inspected.

 

[EfiniX]

EH

I'm getting excited about your enthusiasm to do this! /ubbthreads/images/graemlins/smile.gif

j/k

How about I take a look at it when it's back at your shop to get the broken bolt hold helicoiled?

 

[EHmotorsports]

Yes we can take a look when I fix the valve cover threads.