1995 Celica GT Fuel Smell - Toyota Nation Forum : Toyota Car and Truck Forums

wiley_the_coyote · 08-17-2010, 10:54 AM

My Celica is having some fuel ventilation problems. When I remove the gas cap there is an excessive amount of positive pressure in the tank, as well a a disconcerting amount of heat. I haven't done anything work wise or damage to the car. Not sure what to do.

93celicaconv · 08-17-2010, 05:45 PM

How long have you had the car? If for a long time, is this the first time you've noticed this issue?

Your vintage of Celica will develop pressure, especially if hot outside and if the tank is quite low on fuel. This should be considered normal, in fact good, in that you are not venting fuel vapor to the atmosphere.

You do have an EVAP canister that is made to collect the fuel vapors from the tank, and when called upon by the ECU, will pull those vapors into the intake manifold to burn them off. However, under certain conditions, the ECU does not activate the EVAP system, and when this happens when the fuel tank is near empty and the outside temperature is very warm or hot, you will get a lot of pressure coming out when you remove the fuel cap just prior to filling the fuel tank up.

***MR2Jedi*** · 08-17-2010, 07:52 PM

Agreed. Sounds normal, but you might want to check the hoses to and from the charcoal canister.

wiley_the_coyote · 08-17-2010, 08:00 PM

Thanks for the responses guys. I have had the car a few years and am pretty familiar with it. I think this is different, when I pulled the cap off it took almost 10 minutes to finish venting. the gasoline fumes were almost scalding....

***MR2Jedi*** · 08-17-2010, 08:31 PM

10 minutes!?

93celicaconv · 08-17-2010, 09:33 PM

Where was the last place you bought fuel to fill up your tank? What exactly was the fuel you used (pure no lead, 10% ethanol blend, 20% ethanol blend, 85% ethanol blend)?

Reason for asking is that summer blends of no lead gasoline, considering vapor pressure, can get the tank pressure up towards 12-15 psi. The emptier the tank, the more vapor there is in the space not occupied by liquid. 15-20 gallons of 15 psi vapor will take some time to vent out.

Winter blended gasoline is more volatile, meaning it has a higher vapor pressure at a given temperature. This is used to help fuel ignite better when cooler out. Is it possible the place you last purchased fuel had a winter fuel blend still being sold yet?

And, when you filled up, if it was very hot out, and if you had the engine idling without driving for quite some time, the temperature of the fuel in the tank increases, and the fuel vapor pressure goes up along with it.

So I'm still just wondering if you got in some high volatility fuel and got it hot just before you went to fill your tank. Not sure what else could cause this pressure, because there is nothing in the fuel system that would cause an increase in tank pressure above the normal fuel vapor pressure.

wiley_the_coyote · 08-24-2010, 05:20 PM

I checked with Costco where I bought the gas, they had no idea what blend it is. I wasn't super hot when I filled up either. I found a vacuum line on the manifold broken, I think that may be my problem.

93celicaconv · 08-24-2010, 08:03 PM

Quote:

Originally Posted by wiley_the_coyote

I found a vacuum line on the manifold broken, I think that may be my problem.

I wonder if that vacuum line is from your EVAP charcoal canister. That could explain the fuel vapor smell. Instead of being drawn into the intake manifold, the fuel vapor from the EVAP canister was being vented into your engine compartment as the fuel tank fuel vapor pressure increased.

Might be worth a look to see where that vacuum line goes.