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The mkiv Supra Owners Club

Fuel changes after a few weeks sitting in your tank


rider

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Topic came up on a classic car forum but seeing more and more owners are parking their Supras up for extended periods this might be interesting information, or it might not be, on how the fuel composition changes on sitting in a vented tank over time and what impact that can have on air/fuel ratios. I was surprised at the data but there is no information around storage conditions of delta around the ambient temperature so its a limited in its scope.

 

The shelf life of fuel in sealed solid (not transparent) containers is reckoned at around a year.

 

BP fuel - Petrol life in vehicle tanks

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I had a full tank of fuel which sat for just over two years as I didn't want the tank to rust inside

 

Due to the age of the fuel I didn't boot it due to old fuel... just drove it normal until I had to fill up which didn't take long lol

 

Weather it would of caused any damage or not I don't know but didn't want to risk it

Edited by mplavery (see edit history)
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I had a full tank of fuel which sat for just over two years as I didn't want the tank to rust inside

 

Due to the age of the fuel I didn't boot it due to old fuel... just drove it gently until I had to fill up which didn't take long lol

 

Weather it would of caused any damage or not I don't know but didn't want to risk it

 

The tank is plastic!

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It is the addition of Ethanol content or if you are running E85 might be an issue

 

I was reading up on Fuel the other day , considering a few of us have the Charcoal Canister removed , vented to air as opposed the OEM sealed system

Cars are sitting up during the week , the exposure to the air from what I read caused the fuel to loose its potency quicker , not too sure if it is negligible, maybe the vent line has a not return check valve on it , unless vacuum is applied it remains shut

Edited by Jellybean (see edit history)
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I was having a similar debate with my Dad at the start of winter because of my Supra being sat for a while during the build...

 

If leaving it off the road for a good 6 months if not even slightly longer which of the 2 options would be better...

 

A) Filling the tank up to full so that it has a greater volume of fuel to turn bad so potentially take longer to go bad because of the consistency

 

or

 

B) Leaving the volume of fuel down to a minimum so that you can fill up with fresh fuel sooner and use bad fuel for less time (although potentially being worse fuel for that time because of less volume to attack and go bad)

 

Assuming this is how it works of course as im not up on science and chemical reactions etc... lol

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If planning on storing the car for a couple of years you could just leave a small amount of fuel in the tank, then before starting it top up, pull the fuel feed and bridge the pump to drain the first litre or 2. I'd also crank it a few times without the EFI fuse to circulate the oil before staring, but that's a whole other topic! This is of course playing it safe, plenty I know would just hook up the battery, start it up and drive, probably be fine too 90% of the time

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BP fuel is crap, Esso isn't much better. Supermarkets are crap aside from Tesco 99 but mines fussy! Spits it's toys out and starts pulling the timing on boost unless it's Vpower or E85 so that's what she gets. Stick any old fuel in the run around though!

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I think you lot are thinking too much into this as stated the fuel tank is plastic as is the filler upto the cap so rust I wouldn't worry about.

 

With regards to fuel quality degrading over time I spend allot of time around Marine Engines some more advanced than the 2JZ running higher compression and boost levels and more sensitive to bad fuel (water contamination etc) some not so advanced (Yank V8 crap).

 

some owners stick dry fuel in to counter condensation some don't the end result is generally the same no problems with starting or running under load on generic petrol most leisure boats can go well over 12 months without being started aswell.

 

 

I always leave the Supra for 6 months at a time with barely any fuel in over winter and its fine I am more concerned with keeping salt away from it TBH haha.

 

Always used Tesco 99 if anybody cares but V power performs exactly the same hell I ran all my older Jap scrap on normal 95 and never had any problems actually that's a lie I had a Rev 2 MR2 Turbo that didn't like 95 and ran lumpy until I filled it up with 99.

Edited by MattP (see edit history)
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When I bought my car it was stood for over 5 years in Essex out in the elements, fired up after two chugga duggas on a fully charged battery. Ran perfectly fine but I did toodle to the petrol station to put £30 worth of fresh fuel in it before it's mot.

 

are you the guy who bought that UK spec and welded a new radiator support in?

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