hey guys;
still working on this '97 ram 1/2 ton 4x4 with a 360 and auto.
while no 'flow' of gas off the tank, the gas tank when full after driving is 'leaking' down the side of it...the tank has a visible stain on it and is 'humid' with fule at the bottom. i pulled the inner wheel box fender today so I could get an eye on the problem. from what appears to be a gold anodized vacuum canister on top of the tank, a small hose comes off it and runs down between the frame rails someplace...anyways, that hose looks like it has 'fluid' on it, ie: gas. perhaps the tank is pressurizing and blowing fuel out that hose?

i am going to lift the box tomorow to get a better view as it looks easier than removing the tank, was just wondering if anyone else has had this problem or knows what the canister is or where else the gas may be coming from.

thanks.

 

No canister on top of tank.
If the line you are refering to runs to the drivers side frame rail then I would say that maybe someone added a external fuel filter to the fuel line.
From what I remember there is another line that comes off the fuel pump assy that goes to the carbon canister under the passenger door and another line that is from the rollover valve, I Think..... But nothing like you are saying.
Any way are you sure it is fuel that you see on the gas tank?
or could it be brake fluid from the "Known to rupture brake line above the gas tank"
This brake line runs with the fuel line under the drivers side along and IN the frame rail.

 

no, definately gas...and its definately a gold anodized diaphram of some sort on top of the tank with a plastic line coming off it.
i had problems last week with the carbon canister setting the check engine light, so i pulled the line off it and it started leaking all its charcoal bb's all over, so i drained it out and reassembled and the evap code went away as well as the pronounced gas smell...until i filled the gas tank yesterday, now a little of the smell is back, not as bad as before, prolly from the leak and so is the film of gas on the tank... seems to go away about 3/4 of a tank of gas and less...wondering if rollover diaphram isn't 'plugged' with charcoal bb's and not allowing normal gas 'swish' pressure to escape...
thats assuming that gold anodized diaphram looking unit is the rollover valve you discussed...

 

The little cannister thing is the fuel pressure regulator..... If it is leaking, the level of fuel in the gas tank shouldn't matter. It should leak everytime you shut the engine off.... and possibly while running. Gas leaks are dangerous. This is something you need to address right soon.

 

appreciate the fuel pressure regulator answer...stain on tank could tell the tale that its been leaking for a while...but wouldn't pressure regulator cause a miss or something when vehicle is running?

 

Sounds like it isn't leaking "too bad" (for certain values thereof...... ANY gas leak is a potential health hazard...... in more than one way), and the truck will actually run fine down to 30-35 lbs of pressure, just not as well as it should. The computer can compensate to some extent for low pressure... but there IS a threshold point, where it can no longer keep the injectors open long enough to feed the engine enough gas. First becomes noticeable as a hard to start when cold, progresses to runs bad at higher rpm, and the starting gets harder, and the max RPM gets lower, until it won't run at all.

Not to mention, the pump is quite capable of keeping up with small leaks. The pump can prolly put out 75-100 PSI, that's what the regulator is for.

How's your gas mileage?

 

i thought fuel mileage was ok for what it is...187,000 miles, 4x4, bigger motor... 11-12mpg around town start and stop. no stumbling or hard starting, plenty of pep.
despite all the dirt and dust under there, regulator looks almost new from what i can see...like i said before gold anodized and bright. i purchased vehicle about 2mths ago with a bad trans for $1G. only been driving it like 3 or so weeks so far after trans was rebuilt.
guess i'm use to gm's for the past few years, their fuel pressure regulators r located under the intake plenum, not above gas tank where not easily accessable...lol.