Mystery Fuel smell

[ken007]

I drive a VS SS commodore and have been experiencing a fuel/vapour smell coming from the fuel tank area. It usually occurs after 10 minutes of driving.

Things I have done to try and fix the problem include;
* Changed ruptured fuel vent lines behind rear drivers side wheel where the charcoal cannister is (done a while ago so doubt this is the issue)
* Changed fuel cap
* Changed fuel filter
* Changed fuel pump cork gasket

Fuel smell is still apparent, most obvious sign is from the cork gasket on the fuel pump. I changed this as my mechanic said that it is moist and there seems to be a minor leak. Unfortunatley the new gasket still gets moist & oily and this minor leak runs all the way underneath the fuel tank. I have ensured the screws on the pump were done tight and don't understand how fuel should still leak through the cork gasket so maybe theres a leak from on top of the tank where there are some other fuel lines ??

Another thing that I think is causing this is excessive pressure build up in the fuel tank. I notice this when running half to empty. I understand that it is normal for pressure to build up in the tank but this feels very excessive and the hiss sound it releases is loud and has a little bit of force.

Please help as this is driving me insane!!

 

[Vee-ard]

check that the vapor lines under the car that lead to that one that you repaired near the charcoal canister arent blocked up. pull one off and see if you can blow through it. sounds like if it has a really forceful pressure release when you unscrew the cap, the vapour is building up and isnt getting to the canister like it's supposed to.

I fixed my fuel smell by repairing these lines, they were cracked and disintegrated, so instead of going to the charcoal canister, it was just venting to the atmosphere and the smell would always come into the cabin.

 

[ken007]

thanks Vee-ard! really hope thats the problem.
When i was experiencing similar symptoms a while ago, i discovered that those fuel vent lines were ruptured and once I changed them the smell went. But now the smells back.... I did use thicker lines and longer lines to replace the ruptured ones, maybe they have blocked up as you have mentioned.
Cheers

 

[Vee-ard]

well, if you've only replaced them recently, im not sure that they would have blocked up so soon, but I would still check everythings properly attached and flowing as it should. I ended up having to take my tank off to find another rupture, as well as a new fuel regulator and surge unit.

Best of luck with this mate, it took me forever to fix all my fuel line issues. I didnt give up though, because the car's only done 60,000kms you dont find them like that anymore..

 

[ken007]

I ended up taking the fuel tank off and changed the fuel lines.
* Changed breather line because the old one looked to be damaged
* Changed overflow hose from neck to tank

Noticed on the nipple the breather line attaches onto, there was carbon/rust/particle build up inside of it. I suspected this was the problem as it required a bit of jigging with a wire to clear it up.

When i put it all back, i made sure I can blow through the new fuel lines and into the tank, making sure there was no kink in the lines (pain in the arse). Managed to put it all back on.

I checked my charcoal canister in the engine bay and it seems operable as I can blow through it.

I had mistaken the charcoal canister with the pressure valve behind the drivers side rear wheel. The pressure valve seems to be stubborn as it requires allot of effort to blow through (is this normal ??).

I am also suspect of this line that the valve connects to which leads towards the engine (does it go into the charcoal canister?)
I can blow into the fuel tank side but struggle to blow through the other side towards the engine (again, is this normal ?)

There still seems a bit of a smell and excessive pressure builds up in the tank (when I was running on low)... this is becoming major pain in the backside.

My theory is that the pressure relief valve is either not working as it should, or the vapors or whatever it is meant to bypass the pressure relief valve and into the engine via the charcoal canister, does not get through. Sensing there is a blockage along the way hence the pressure build up in the tank as it cannot vent properly.
Makes sense ?

 

[delcowizzid]

theres a purge solinoid on the rear of the engine that opens under certian circamstances its controlled by the ecu if its not opening it wont have anywhere to vent the fumes and will build up pressure

 

[CalaisJohn]

was doing some research a while back on a new fuel pump for my Calais, I recall that the screws/bolts retaining it to the tank had to be replaced, ie: "NEW". I can't r'memba why tho.. hope it may help some