NSeagle78

iTrader: (5)

I have a 1992 SC400 and do not know if this is normal or not. I filled my tank and left the car running when I got home. I was getting ready to add an additive to the tank. I removed the gas cap with the car on and fuel ran down the side of my car. It appeared that the gas was forced out of the opening as long as the cap was off. Also my gas drain line was clogged, I repaired that but I do not think that it had much to do with anything. Is this normal? HELP

Ali SC3

iTrader: (10)

whats a gas drain line and how did you repair it. sounds like theres pressure in the tank. the vent hose that goes to the canister in the front of the car is what relieves the pressure/vapor that builds up in the tank. if you are talking about that being clogged then it would build pressure in the tank which is not a good thing. when you open the cap you are releasing the pressure and fuel will come out with it.

NSeagle78

iTrader: (5)

I am sure that I am useing the wrong terminology but there is a drain hose directly below the gas inlet point. This line runs thru the trunk down pass the amp and out of the car. What do you recommend that I do? How do I find the canister in the front of the car and if it is clogged how do I unglog it?
Thanks in advance

Ali SC3

iTrader: (10)

i don't know much about that drain hose you're talking about or how to fix your problem exactly, I was just giving you an idea of somewhere to start.

good2go

iTrader: (6)

I think he's just referring the the overflow drain that's supposed to redirect any gasoline that overflowed while filling up so that it doesn't run down the side of the car. Regardless, unless you overfilled your gas tank to the point that there was no room for thermal expansion of the gasoline, it sounds like the breather line (as was mentioned already) or check valve to the charcoal canister is clogged. I am sure there is a procedure in the manual for checking the charcoal canister lines (it's located on engine side of the firewall directly behind the glovebox) and the check valve.

here's some relevant info just off the top of a google search:

http://www.justanswer.com/questions/...nes-on-the-car

Photon440

iTrader: (3)

Hello NSeagle78. I'm going to guess that when you say drain hose, you're talking about the opening right at the bottom of the filler pocket when the gas tank fill door is open. That's just there to let out rain and wash water that gets in the door, it has nothing to do with the pressure you're experiencing. Good idea to keep it cleaned out though.

As for the fuel tank pressure, that is normal. Do a search on here and you'll find several threads talking about it, including warnings that you'll have fuel coming out if you open the cap when the tank is full. Treat it as a good sign - you have a proper seal on your cap and its check valve. According to the shop manual, the check valve is there to allow air in when the tank has a vacuum, but close it to prevent vapour loss when there's pressure. This pressure also tells you that the charcoal cannister check valves are doing their job.

In short, nothing to worry about. It's normal. Next time you're putting in additive, pour it in at the gas station while the cap is already off.

-=Photon=-

good2go

iTrader: (6)

Is this true??!!?? I don't see how it can be normal unless there is inadequate expansion room in the tank/filler neck. No manufacturer is going to engineer a fuel system that back flows gasoline if you open the gas cap in between fill-ups. Their liability would be astronomical.

Photon440

iTrader: (3)

Well, as I stated earlier this problem has been discussed in several prior threads. For one, I think Toyota counted on people removing the gas cap when the tank needed fueling, not when already full. Then again, perhaps they made a mistake and we can have a free new gas tank installed with the proper recall mods done to it. Probably not though

We don't know all the details about this particular case. Perhaps the car was not sitting completely level and the filler side was slightly lower. Then again, NSeagle78 did mention that he was taking the cap off of a car with a running engine. I don't think Toyota/Lexus would recommend this, although I haven't gone to look it up in the owner's manual.

My car almost always blows out a lot of pressure when I remove the cap to refuel, but I haven't tried it with a full tank.

-=Photon=-

NSeagle78

iTrader: (5)

Thanks guys for the help and quick response. I did the same thing today but I did not get an overflow of gas. I am hoping something was stuck, however with the paper clip check I threw codes 13 and 31, I disconnected the battery for the rest of the day. I will wait and see if they come back up with the check engine light.