capn tibs

The past few days my gas cap hisses when I unscrew it and when I go to put gas in it I can only put a half a gallon at first and then less then that in small increments until I get about maybe 2 gallons in the car (enough to get me to work and back). If I try to fill up faster the gas will actually overflow and spill out. I have had a similar problem before but not with the overflowing and the problem just went away after I read some threads and found out that it was probably caused by topping off.

Now, I don't top off ever, I do typically fill the tank as much as it pumps with the trigger locked tho. I have also been running a CEL Code for the past week P0446 Evaporative emission (EVAP) system, vent control �“ circuit malfunction Wiring, EVAP canister purge valve, ECM.

Any help to figure out my problems would be greatly appreciated!

Bullfrog

You asnswered your own problem, your EVAP is not working correctly, that includes how your gas tank vents when filling up. The air has to go someplace, like back out the filler valve, pushing the fuel out of the way.

capn tibs

I know its something within my EVAP system but why would gas not be going down into my tank?

Bullfrog

same principal as when you turn a 5 gal water jug full over, the air is going up and since the filler valve is so small you have air comming back up pushing fuel out.

capn tibs

i get what your saying bull, i wasn't really thinking about it like that but that should be basic science.

I pulled this diagram off of HMA to better discuss/ diagnos the possible issues.

Since the fuel cap only releases gas to the fuel tank by a 1-5/8" filler hose and a 1/4" Vapor Hose and my fuel is not getting all the way into the fuel tank it should one of those two hoses or the one way valve on the vapor hose could be broke that could be the problem...right?

Bullfrog

That or your canister close valve is not working because your purge control valve is closed at fillup. Thats the only other thing i can think of that could be pressurizing your system. It even says that the vent valve goes out when refueling so if its stuck then you are building pressure.

capn tibs

after a little further research I found this information in HMA

P0446 Evap. emission control system canister close valve permanently closed Evaporative Emission Control System

So it's most likely (99%) just what you said bull. My canister close valve is stuck and not working correctly.

Bullfrog

Sorry to be right. I had a p0441 code that had to get rid of a while back. Good thinking working looking at the diagram though.

javageek

I think it was $15 when I bought one for my first RD.