22 replies to this topic

[Steam]

What are the symptoms of stale fuel, do they always manifest in the same way or can different poor running issues occur at different times?

[Spider]

I've had different effects from it. Our fuels are different between Summer & Winter which I suspect in part might explain the varying effects.

In the least, I've had just poor performance, the odd miss perhaps. At the other end of the spectrum, it's been a huge loss of Octane, resulting in pinking at the slightest of throttle openings. In between, just very poor performance combined with a rapid tendency to run hot when some load is applied.

Be aware, at least here in Oz, most of the Fuel Distributors only guarantee fuel specification for 4 weeks from when they deliver it to the retailer. How long they have it before you buy it is the $64,000 question.

[Steam]

Thanks Spider, trying to sort an unexpected hesitation /misfire umder load. The only variable is fuel. Last time I had stale fuel it wouldn't idle.
I topped up with fresh which seemed to improve it somewhat but now its back. I am going to drain it and fill fresh when the shed is more comfortable.

[Spider]

I have found with stale fuel, usually, I need to run every last drop of it out. Just adding fresh fuel doesn't always seem to help.

[Steam]

Yes I can understand that, also where I fuelled up may not have the biggest turnover of 98 so may have compounded the problem.
Previous instances the car just ran poorly and a fresh fill fixed Immediately or I have experienced poor idle which again was fixed with fresh top up. No 2 problems are alike.
But as you say diluting fresh with old is probably not a good idea.

Edited by Steam, 05 January 2024 - 08:34 AM.

[Spider]

I have a theory regarding 98 in recent years, but I stress, it's only speculation.

 

I can't recall the trigger for it, but about 2 or 3 years back, he had a fuel price spike, a big one. 98 of course also went up in price, but it seemed to go up a disproportionately more than the 91 & 95. As a result, I feel in some areas, retailers were turning over their 98 much slower than was previous. I can't help but feel, if there's any truth in this, that you'd be more likely to get stale 98 than any other fuel.

I know with certainty, when traveling through the rural areas, those that had 98 was certainly stale.

I've de-tuned the Moke to run on 95 now days.

[Steam]

What you say makes perfect sense as usual.

Assuming 98 is mostly stale then I see a few options. Hereabouts the choices are 91 or 98, no 95.

The engine is a HC but a late model head so would tuning to 91 be an option ?

Using an octane booster, whether these actually work is another can of worms.

stick as it is and deal with poor fuel quality as it arises.

[Sovereign01]

Sounds like I should have run the old fuel out completely, the needle was on the red when I filled the car up with a fresh tankful. I had hoped to notice some improvement in the car's performance when I did that but it didn't seem to make any difference.

[Spider]

Another experience I've had that just came to mind.

 

I'm not sure how it's happened (without pointing fingers !) but it seems from time to time, I've had normal unleaded or either 95 and 98 that's been contaminated with ethanol fuels. Of course, as that sits in a fuel tank, over a fairly short period of time, it separates. When that happens, that's water on the bottom of the tank, with the fuel above it. It doesn't need much at all to through the spanner in the works.

This too I suspect explains why in some instances just topping up makes little to no difference.

 

 

Sounds like I should have run the old fuel out completely, the needle was on the red when I filled the car up with a fresh tankful. I had hoped to notice some improvement in the car's performance when I did that but it didn't seem to make any difference.

 

[IronmanG]

https://sustainclass..._ajQ_qAwMMEYbRs

Just seen this. 12 month shelf life. Has anyone tried alternative fuels?

[KTS]

an interesting development, but given that prices seems to start at £3.80 a litre and with only 2 stockists in the UK (so far) i can't see me switching just yet

[IronmanG]

an interesting development, but given that prices seems to start at £3.80 a litre and with only 2 stockists in the UK (so far) i can't see me switching just yet

Yep agreed. Might be good to leave a few litres in the tank over winter though.

[Shooter63]

an interesting development, but given that prices seems to start at £3.80 a litre and with only 2 stockists in the UK (so far) i can't see me switching just yet

Just fill your tank with 100LL it will stop the rot and is around £1.80 per litre cheaper, as a bonus when you drive your mini it'll smell like a race car.

Shooter

[Spider]

There are fuel preservers available. They generally extend the life of stored fuel out about 6 - 9 months.

Just be aware, they are a preserver though, so they need to be added to fresh fuel. They won't bring fuel back from the dead !

 

There'd be little point n using it if you are driving your Mini often, but when winter comes and you are likely to park it up, that's the time to add it then.

[IronmanG]

There are fuel preservers available. They generally extend the life of stored fuel out about 6 - 9 months.

Just be aware, they are a preserver though, so they need to be added to fresh fuel. They won't bring fuel back from the dead !

There'd be little point n using it if you are driving your Mini often, but when winter comes and you are likely to park it up, that's the time to add it then.

Any particular make you can recommend