2003 2500hd gas tank pressure

[deltaboy]

Heard a whining when I shut the truck down. Went to put gas in and a lot of pressure blew out when I took fuel cap off. No codes but there is pressure every time I take the cap off. I hear the whining every time I shut off the engine, and I do not remember hearing it before the pressure started. Is there a stopped up vent, and if there is where is it? The whining is not a mechanical sound like the fuel pump. Thanks for any ideas

[j cAT]

Originally Posted by deltaboy

Heard a whining when I shut the truck down. Went to put gas in and a lot of pressure blew out when I took fuel cap off. No codes but there is pressure every time I take the cap off. I hear the whining every time I shut off the engine, and I do not remember hearing it before the pressure started. Is there a stopped up vent, and if there is where is it? The whining is not a mechanical sound like the fuel pump. Thanks for any ideas

first off you should never ever have pressure in the gas tank ....never.....


yes it is very possibly that the vent valve is blocked plugged with debris ...do you drive on dusty off roading type surfaces ? if so this is most likely the problem....this is located at the gas tank cannister area....in the forum there is a very good post giving pictures and also the tsb that explains all....


all gas vapors are sent to cannister to be stored then burned by engine , the computer should have given you a check engine LT then the code should direct you to where the problem lies...the computer monitors gas tank pressures/vacuum....