Fueling & Injection - Bad pump? Removed filter, all gas leaked out

Anyone have gas in tank leak or get siphoned out just by removing fuel filter? I assumed only gas in the line would drain out? The entire tank drained out when i removed the filter. I'm guessing all the pump components dissolved or corrosive damage.

Some history. Car sat idle for almost six years with about 5 gallons of fuel. I added a fuel additive and filled with new fuel without draining tank. Replaced battery and car started right up. Funny smokes and smell for 10-15 minutes; eveything cleared up after that.

Car even drove fine for approximately five miles. Now no fuel at the rail. This is when i removed fuel filter to replace and all gas drained from tank. New filter is on and a gallon of fuel was added to tank. I can hear the pump, but still no gas at rail.

Bad pump? Replace pump only or entire assembly(expensive)?

Thanks,

was the gas cap on the entire time?

Yes. Only prep was disconnect battery.

there was probably some pressure built up in the tank and when the filter was removed the gas had to go somewhere..

best way to diagnose the pump is with a fuel pressure gauge and a lab scope to get a wave form

Finally pulled the pump. The assembly broke at the cap/top of tank; which snapped the intake line at the pump. So once i pulled the filter, gravity did it's thing.

Now I'm trying to find after market assembly. Looks like everyone just uses stock assembly (modified) with after market pumps. These assemblies are expensive for cheap ass plastic; $350-500 depending on brand.

I have new buckets/senders for the 99-02 f-bodies.

I can also fit one with a new Racetronx pump if interested.

Please call for more info.