Technical Supermarket fuel

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Technical Supermarket fuel

barnettgs

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Surprised that there's no (or little) discussion of supermarket fuel in this forum.

See my other post last month - https://www.fiatforum.com/panda-iii/422549-initial-start-up-ignition-2.html?p=4054048

Also you can read about Branded vs Supermarket fuels - www.simplemotoring.co.uk/supermarket-vs-branded-fuels/

The reason I'm posting this is that I have found my Panda 1.2 Easy quite sluggish with Tesco's unleaded fuel, especially on pulling off. It happened shortly after it had its first fill-up with Tesco fuel and I thought it was due to the engine being new. However, I switched to different brand such as Texaco and Maxol, it has been great since then.

Last week, my car was cutting out unexpectedly when I tried pulling out of the junction and I was a bit puzzled at first but then I remembered that I had my car filled up with Tesco fuel a few days earlier and it continued struggling to pull out of junctions or hill smoothly. Leaving the throttle alone while lifting the clutch didn't work as well as it normally do.

All is well again after I filled it up with Texaco's last Saturday!

From now on, Tesco petrol is no-no! :nono:
 
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One of the reasons I try to fill up when the tank is half full. A habit I got into when running cars that required 4 or 5 star leaded.


Cheers
Bob
 
I've trundled up and down from Notts to Wiltshire/Berkshire every week for 4 years in 3 different cars. A 2 litre diesel, a 1.8 turbo petrol Auto and a 1.6 Mx5. - I have run extended periods on Shell and Shell Premium as well as Asda and Morrisons. I haven't noticed any difference in fuel economy between the brands. I can only assume that traffic variance has a bigger effect than the petrol. What I can say though, is that having swapped worn Michelin Energy tyres for new ones (same brand) i've lost 4 mpg!!
 
Regularly fill up at Tesco, Asda and Shell, tried the premium unleaded too though I was 99.9% certain that the Cross's ECU couldn't make the most of it and sure enough absolutely no difference between any of them that was noticeable in day to day driving. Improved detergents on the Super unleaded may make a long term difference though.

The only car I have ever owned that has "noticed" a difference in fuel grade/quality was an Alfa 156 GTA which seemed to go from very quick to disturbingly so when fed Shell Optimax.
 
I'm seriously regrettng running my 4x4 on Asda unleaded. Feels like it's pulled a muscle as it were. Oh the irony that they have Redex on offer for £2. Texaco unleaded only 1p litre more, but don't want to go past home for fuel then have to turn round again. Super Unleaded has helped pull in 2nd gear at low speed but didn't notice anything beyond that.
 
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...What I can say though, is that having swapped worn Michelin Energy tyres for new ones (same brand) i've lost 4 mpg!!
Remember that the difference in wheel diameter between a worn tire (say 2mm tread) and a new tyre (8mm tread) has an effect on distance covered per wheel rotation... but the mileometer (and speedo) don't know about this. Also, the deeper tread means more grip, or more resistance.
 
Hi.
Well I've used many different fuels in my 1.2 from BP to Morrison's, Shell and Tesco.
Any sluggishness and hesitancy has been due to the rubbish spark plugs fitted as standard and oil contamination of the MAP sensor. Since I fitted Denso iridium plugs and an oil catch tank I've not had any issues no matter where and what grade of petrol I use.
I'd also recommend removing the clutch switch on your 1.2 as well.
A friend of mine is a tanker driver and he has told me on countless times the fuel all comes from the same tanks at the refinery, fuel can on occasions come from foreign refineries even going to the major companies too. The fuel additive package is added to the tanker for the end customer.
 
One factor that's completely outside your control is the percentage of ethanol in the fuel. For stability reasons, ethanol is blended into the fuel just before it leaves the refinery. In the UK, petrol can contain up to 5%, but any particular batch can contain less than this, or even none at all. So the same fuel bought on different days could contain a different percentage.

The greater the percentage of ethanol, the worse your fuel economy will be, as the energy content of fuels blended with ethanol is lower.

If (when?) we go to E10 in the UK, the problem will get worse. Interesting article here.
 
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I have an Esso station at the bottom of the road, usually 5p/l more than 12 miles away, so I fill up when in Swindon whenever possible. Mostly use Sainsbury's, but also often ASDA, occasionally Tesco. Choice based on location mostly. Not had any problems with any of it.

Leaving the throttle alone while lifting the clutch didn't work as well as it normally do.

This is poor driving practice. With any engine you should always raise the engine speed before finding the clutch bite point. Sadly, as this requires more skill and dexterity, most instructors teach the lazy way of clutch bite first. Some engines will not tolerate clutch first.

The engine ECU holds tickover. If the engine speed decreases due to a load, such as aircon, or clutch bite, the ECU increases the fuel input.
As soon as you move the accelerator, it sends a signal to the ECU that you will now determine how much fuel goes into the engine, so this overrides the current ECU auto-input. The first movement of the accelerator will ask for more fuel than the base tickover, but likely less than the increased amount to maintain tickover, so the ECU momentarily reduces the fuel input, as you are trying to accelerate into a junction. This often gives a little dip in the engine power, depending on how quickly the accelerator is being pressed. With a hesitant learner that hesitation is often a little frightening! It can often cause a stall. Quite an issue with the latest 1.2 as seen on another thread.

Pulling away without the accelerator first also increases piston/bore wear due to the heavier load.
 
Bill makes some very good points, especially on moving off and how to use the bite point. The snag though with the Euro 6 1.2 is the additional effect of the clutch switch. Even for drivers like myself with IAM & ROSPA it is a PITA, so an inexperienced driver would begin to not only dislike the car but also could get into trouble.

It though would seem that a lot of the running issues with the Euro 6 Fire unit could be down to head design, although the engine is brilliant the constraints of the original design doesn't lend itself to Euro 6 emissions control without lack of low speed torque and hesitation that many complained about. Perhaps its now run its course and the new firefly will be the solution.

All 1.2 owners should remove the clutch switch.
 
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I've put Shell Fuelsave in today. Seems to have negligible ethanol in if that issue with Asda's. Why Shell still allowed to call it that when their claimed extra 21 miles per average tank got pulled as apparently made no difference. Last tankful 31.9 mpg with calculator. Thirsty but am used to it. :cry:
 
Fuelly to me is handy although a spreadsheet could do the same. As it records every fill up and miles travelled it eventually will give a very accurate average consumption. I'm pleased with my figure but in real terms my running is around 80% town and short runs.
I can't complain one little bit as my previous Rover 75 2.5V6 did an average of 19mpg on the trip over a year so it would be less as these are always optimistic.
 
Advice appreciated. While I know Super Unleaded has cleaning properties and does react with the knock sensor that I believe the Twin Air has, am considering going back to 95 octane supermarket fuel with ethanol content just because easier to get hold of. Is it worth travelling especially for branded fuel as car going to run like a complete dog otherwise. Then have to add Super Unleaded for couple of tanks again to clean it out. :bang:
 
Certainly the FIRE engine seems rather untroubled with supermarket petrol. It doesn't like Tesco momentum though as it coughs and splutters. I've used Morrison's petrol just the 95 stuff and its fine.
 
Settled for Asda 95 and compared to Shell V Power saved around £4. Won't go as well but will need more fuel in under a week anyway. There's Texaco near where buy my lunch for work, doubt fuel will last until a Saturday, will see. :eek:
 
Just a thought, as an Euro 6 4x4 m-jet driver, has anyone compared using the more expensive diesel over the standard stuff?
 
Used to use BP Ultimate Diesel in 2010. Little cleaner and perkier. Paid for itself in couple of mpg more. Though as fuel station on dual carriageway could average good mpg instantly due to instant average speed of 65 mph. Nowadays the fuel would burn more completely so not fill dpf as often. At least that's the theory. You'd get nearer to 2 years before needing an oil change maybe. Though I'd have changed every year, or twice a year on the Twin Air.
 
Our TA 4x4 dislikes the BP regular petrol - stutters and fluffs far more than on any other brand (including supermarket fuels). Unfortunately BP is our local garage, so if we’re running low and need to use the local garage, it gets a tank of Super Unleaded, on which it flies (and seems to produce better mpg too). For a couple of extra quid on a tank, it’s not worth suffering the rougher running of ‘regular’. Appreciate that logic would suggest this shouldn’t be the case, but the TwinAir engine definitely seems more susceptible to fuel quality than most.
 
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