Gas tank anti-siphon

meliss · Apr 12, 2017

Hey all,
I've got a 2002. Awhile back I dropped the gas tank to drill some holes into the rear cross member. Before I did that, I siphoned the tank to minimize the weight. I knew there was an anti-siphon installed, and from what I've read on here, it's a cage with a ball inside. In order to try to get through that cage, I used 1/4" john guest tubing, and that seemed to work just fine. When I was pulling the tubing back out of the tank at one point, I encountered a lot of resistance. So I'm pretty sure I bent the cage, or got that floating ball jammed somehow.

Now, when I'm filling up the tank, the pump trips off over and over. This did not happen before I screwed with the gas tank.

I'd like to take a look at that cage and see if i can fix it, if that is the problem. Can I get to it without lowering the tank again? Does anyone know where, exactly, it's located (inside the tank, filler tube, right where the filler tube meets the tank, etc.)

I have looked extensively on the forum and the googles for pictures and haven't really had much luck.

Thanks in advance!

Ironhead Jed · Apr 12, 2017

not sure if its the same as an 06, but in 06 its built in to the tank filler neck attachment thingy.....technical term.

this pic was taken with the tank installed with the filler neck hose removed. it would be tight, but there should be enough room for an inspection and maybe even a fix.

RUBI 4 MY MRS · Apr 12, 2017

It is not an anti siphon valve it is called an inlet check vale (ICV) which is supposedly used to keep fuel from spilling out in case of a roll over.

Like Jed, I’m not sure if yours is the same as the ’05-‘06s (the tanks changed in '05) but it probably is similar. The ’05-‘06s are known to stick, usually open, causing fuel to spit back on fill up but when they happen to stick closed it takes forever to fill up. Most recommend pushing a long screwdriver or similar object against the check valve to get it open. That might cause it to stick open so consider that & don’t get too aggressive. On our later ones we would rather have it stick open than closed & have a mod that fixes the spit back issue but don’t think that will fit your earlier tank due to a different inlet size (not sure about that). I think if you remove the hose & filler neck assembly from the tub you can see & access the ICV like Jed’s photo above.

Here is the mod in case you are interested.

'05-'06 gas overflow fix
http://www.wranglerforum.com/f5/2005-2006-tj-lj-fix-for-gas-overflow-issue-143837.html

Wrangaleer · Apr 12, 2017

If you lower the tank again use tie down straps and it is easy. It is best to run the tank low on fuel first but a few gallons are easy to handle with the straps.

I would drop the tank to fix the overflow check valve.

meliss · Apr 15, 2017

I was able to get the tank back down today and take a look. This spring was out of position, and I pulled it out of the tank. The ball is not flexible enough to pull from this cage, so I'm going to try to put the spring back beneath the ball from here using some old dental tools. If not, then I'll have to pull the fuel pump assembly to get to it from inside the tank. There is absolutely nothing about this part of the tank in the Chrysler service manual.

jpfelix · Apr 15, 2017

Gas tank anti-siphon

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