1998 mitsubishi challenger noise in fuel tank

"It could be the end of a jiggle syphon hose"

That is exactly what I found inside my tank soon after I bought the car. After removing the tank and getting it out, I couldn't for the life of me work out what it was until my next door neighbour identified it.

Nearly all vehicles built in the last 25 yrs have a valve or restriction in the filler pipe to prevent fuel siphoning (anti-theft protection). Are Mitsy-Bitsy so tight, they don't even provide this basic protection?

I would have thought a clunking noise in the tank would be the filter over the end of the suction pipe had come loose. The length of time the car has been owned is a crucial point.

Nah that restrictor in the filler neck is! ...was! for so you could only get the ULP pump nozzle to fill your car if it was designed to run on ULP.

Super or LRP had a fatter nozzle that would not fit in the ULP tank and the flap insured that the petrol flow would cut off.

Cheers.

Roughasguts - I'm not talking about the restrictor in the filler neck. Nearly all vehicles have a restriction in the lower section of the filler pipe down near the tank, that is an anti-siphoning measure.
Do a Google search on "siphoning fuel" and see how many young blokes on forums are wailing about why they can't suck any fuel out of their car fuel tank with a hose?!

Cheers - Ron.

Oh okay Ron didn't know that! ....But so far I have not had a problem with a 10mm hose pushed down into me tank. I run 10 litres out every so often for the Garden stuff.

Actually 1 Mitsi and 2 x Toyotas from 1994 to 2004.

Cheers.

Yeah, if they haven't got a specific anti-theft, siphon-stopper installed, the filler pipe normally has a one-way valve, that lets fuel in and stops vapours from getting out.
This is part of the vapour-control system that prevents fuel vapours from escaping into the atmosphere, that has been part of pollution controls since the late 1970's.

Cheers - Ron.