Advice for draining four year old gas out of my $2010 GTX?

Got the GTX ignition/accessory wiring rerouted last night; initial testing lit up the dash beautifully. We won't be able to test the ignition itself until we drain the 4 year old gas (or lacquer thinner/tar, now). According to the newly powered fuel gauge, I have more the 3/4ths of a tank of petroleum substance in there.

The current plan is to run a hose from the fuel filter to a bucket, power it up to run the fuel pump and hope for the best...

Any advice, "gotchas," or better plans? And once the old gas is out, should I pull the tank (which I'm told on the GTX is a super PITA) to clean it, or just keep flushing fresh gas through?

-doll

Check to see if there's a drain plug in the tank first - Miatas of similar vintage had one. Otherwise, I'm all for your plan.

And before you drain it, make sure you have someplace to dump it. I drained a gas tank (15 year old gas, came out like syrup) and had a heck of a time trying to get rid of it. The local waste management had "hazardous dumping day" every THREE years......

-Rob

And depending on the car make sure you don't run the pump dry as it can kill the pump in some models.

Maybe a stupid question. but would a couple bottles of something like marvel mystery oil, seafoam or even straight acetone break the gas down enough to just burn it out?

mrwillie wrote: Maybe a stupid question. but would a couple bottles of something like marvel mystery oil, seafoam or even straight acetone break the gas down enough to just burn it out?

Gasoline naturally breaks down into its base hydrocarbon chains and whatever additives the oil company tossed in pretty quick without a stabilizer; if I remember correctly, 60-90 days for cheaper/less additive gasses and up to a year for the better stuff. At least, this is what I learned as a chemistry major once upon a time.

My concern is how gummy the base products get over the years. I could be dealing with a thick or sludgy liquid; I could be dealing with tarballs. No clue. Either way, you don't want to pipe it into the engine.

I don't know 323s but making some assumptions, could you access the fuel tank from the top through the pump mounting plate and siphon the old gas out the old fashioned way (get a siphon setup from the local pet store, sold for fish tanks, and extend the lines as needed)? I don't know if there's access under the rear seat or the hatch area but if there is that way you're not running tarballs and crap trough the pump, and as a bonus you might be able to see what's in there.

I have done this a few times in the past in various ways depending on the vehicle, my advice is:

Check twice for a drain plug or top access to the tank, it really is the easiest.

After 4 years, the gas will be have separated but probably will not be thick or gummy yet. I drained 8 year old gas once that was still all very fluid.

I often work on my car alone in a secluded area, which can be less then safe. In my opinion this job requires an assistant on hand with a fire extinguisher ready to go.

good luck.

Really great & helpful info, guys. I'll see about accessing the tank some other way than running through the fuel pump. Thanks!

The other guys covered fuel extraction, for disposal I recommend fire.

Please post pictures/video of the conflagration.

ansonivan wrote: The other guys covered fuel extraction, for disposal I recommend fire. Please post pictures/video of the conflagration.

Paying attention, as I have a GTX to also do this to soon :)

I want to see conflagration pics as well.

About getting into the tank; is there an access cover inside the car? From my daze at the Mazda/VW place, I seem to remember there was an access plate under the rear seat which allowed removal of the pump without dropping the tank.

If the fuel is still reasonably liquid, it shouldn't be a problem to drain/clean the tank. If it's turned into that brownish gold crusty crap at the bottom, that stuff is hell to remove. Best way (and this involves removal of the tank): heat it from the outside with a hot air gun. Takes just a few seconds to break loose a 4-6" diameter chunk, then move to the next spot. I have heard of doing this with a propane torch.

Four year old gas might run. I have bought cars that were sitting for four years and driven them home. They run like crap but will usually run. The nose knows. If there is any "bite" to the smell it will probably run. If it is kind of sweet, probably not.

I know my almost 5yr sitting (started with jumper box and moved randomly around a property) starts and runs... still have to get the darn thing home though.

my first 944 had around half tank of 6 year old gas in it. i started it, drove it to the local shell station, and filled it with 94 octane. it started running better in about 3 minutes, and by the end of the next fillup (again with 94) it ran like it had a fresh tune. if it's good enough for my car, it's better than your POS deserves.

I'm looking at the fuel tank schematic on Mazdaspeed Motorsports right now. There should be a drain plug on the bottom of the fuel tank. Bring Easy-Outs, drill bits, etc. just in case.

AngryCorvair wrote: my first 944 had around half tank of 6 year old gas in it.... *snip* ...if it's good enough for my car, it's better than your POS deserves.

HEY! Just because it's a 20+ year old soulless Japanese appliance doesn't make it a POS!

I prefer to think of it as a coprolite.

-doll

I've seen a Miata clog up its fuel injectors just sitting in our shop for something between 12 and 18 months. Depends on the fuel that was in it.

And competing in the WRC adds soul to any car!

RexSeven wrote: I'm looking at the fuel tank schematic on Mazdaspeed Motorsports right now. There should be a drain plug on the bottom of the fuel tank. Bring Easy-Outs, drill bits, etc. just in case.

Drilling the bottom of 3/4 full gas tank? Please, pretty please film this.

Also, I think the GTX's have a twin sump gas tank (to make room for the driveshaft) so you will need to make sure you drain both sides if using a hose or something. IIRC, there is a crossover pump to move gas from one side to the other.

dollraves wrote: The current plan is to run a hose from the fuel filter to a bucket, power it up to run the fuel pump and hope for the best...

That's about it.

Are you sure the fuel is bad? I've driven on 7 year old fuel before and it worked just fine.

bought one that sat 11 years with 3/4 tank in it. i got a can and dropped in 5 gal of 94 to fill it, and drove it empty. stalled a couple times but then filled up with nice fresh 87 and it was great for me until i sold it a few years later.

Are you sure the fuel is bad? I've driven on 7 year old fuel before and it worked just fine.

No idea, honestly, but it was stored in a very dry, hot climate (Utah) for almost three of those four years. I not willing to take any chances since I have to drive this thing cross-country. I'm willing to sacrifice the fuel pump since I have a spare. :D

HEY! Just because it's a 20+ year old soulless Japanese appliance doesn't make it a POS!

It's a GTX. It most certainly isn't soulless. It has a soul, it's just under contract to Satan, that's all.