I've let my 2004 Z06 sit until I fear the gas in it is old and I'd rather just get it out and put fresh gas in it. It has almost a half tank of gas in it.

I'm an old school guy and somewhat new to fuel injection. Can I just rig a hose to the fuel rail fitting and dump it in a gas can to get the old fuel out?

Thanks

 

Not sure how you're going to be able to "dump" it in a gas can since the FP won't run unless the engine's running. The only exception to that is when you first turn the key on, the pcm triggers the fuel pump "on" for 2 seconds to pressurize the fuel system then shuts off automatically (unless the engine starts), so unless your going to sit there and constantly turn the key on and off it ain't happening.

Since you have an '04 (with the "FFS" fuel system) you have the additional problem of ALL of your fuel tank fittings being on the top of your fuel tanks and inaccessible without dropping/lowering your tank(s) first.

There is a way to manually by-pass the fuel pump relay (using a jumper wire) and kick on the fuel pump and let it do the pumping, but I would caution to NOT try to get every last bit of fuel out for fear of overheating/damaging the fuel pump as the level drops. The fuel itself serves to cool the pump and when the level gets extremely low you run the risk of partially exposing the pump. Although the pump itself sits inside a "bucket" in the tank to help with this, it can still happen if carried to the extreme. At least don't try to do it all-at-once. Pump a little, turn off awhile, pump a little, etc giving the pump a chance to cool off as you go. Besides, you're not going to be able to get every last bit of fuel out anyway. If you use that method, you would remove the Schrader valve on the fuel rail and clamp a fuel hose over the end and run it into a container. Clamp it securely. Do NOT try to just slip a hose on. The system operates at 58psi and will blow that hose right off the fuel rail, or at at a minimum leak like Hell.

This subject has come up before. Try a search to see how others have used the relay-jumper method in more detail.

HTH

P.S. I've never tried to insert a fuel hose directly into the fuel tank at the filler tube before, so I don't know for sure if there is an "anti-siphon" screen, or something similar, inside the filler tube that would block it from going into the tank. The problem is, even if there's not a screen and you can insert a hose into the "tank", you're only going to be able to siphon/pump out the driver's side tank and not touch the passenger side tank at all.

 

How much time are you talking here? Assuming no STA-BIL or similar was used? With a half tank, I'd top it off with fresh fuel.

It's not going to be easy (or safe) as pointed out above. Unless there's evidence that the fuel has deteriorated to "varnish", you should still be able to start and drive. As the level drops, add more fresh fuel or maybe some octane booster. Don't expect the octane booster to add much though unless you can find TORCO or maybe NOS. If you use octane booster, make sure you check your spark plugs after use.

 

It would have to be a year or so before I would consider pumping it out. Otherwise, fill it up with fresh and top it off at 1/2 again.

 

Modern Gasoline doesn't varnish as quickly as it did in the old days. Unless its been longer than a couple of years I'd just top it off and drive it.

 

Like everyone else says, fill it up and drive it! Heck, I keep my boat tank FULL all winter (38 gallons) and it runs great after sitting in the garage for 7-9 months..

 

I too think driving it is the best solution, after maybe putting in a bottle of Techron and then filling with fresh. Truly stale or contaminated gasoline has a very different odor than fresh, so if you could get some of your existing fuel out to smell and it still smells like gasoline you would have less worry. Maybe tap some off the fuel rail at the valve; I don't know if a hose into the filler tube can make it in to pick up any gas via siphoning for sampling--I'm not familiar with the construction.