98 octane fuel

M3 hacker · 10-04-2021, 08:19 PM

Has anyone experienced idle problems (fluctuation) when using 98 octane fuels? I have tried different fuel brands and all of them are the same.

My car is idling badly and doesn’t have any fault codes. I’ve changed the breather valve, idle control valve and fuel cap with no luck.

I can vaguely remember reading somewhere that in Australia using 95 octane fix their problem and it was actually better?

I’ve got an Alpine stage 2 98 tune and a bit hesitant using 95.

Thanks for any help in advance…

Steve

HiFi · 10-04-2021, 09:32 PM

i believe the Alpine 98 tune is too agressive for our low quality fuel. our 98 isnt the same as US 98(93 RON). You might want to get an alpine tune for 95 instead, and keep running 98 fuel. BP is geernally the best.

ABC99G · 10-04-2021, 11:40 PM

You could try replacing the spark plugs.

Fezza · 10-05-2021, 03:07 AM

Can also get Alex to send you a 95 RON tune. Had issues with 98 as well until I changed over to Mobil branded 98 fuels from 7-11 and Costco.

M3 hacker · 10-05-2021, 04:03 AM

Quote:

Originally Posted by ABC99G

You could try replacing the spark plugs.

Yeah I thought about that, but the plugs are only 1000km old.

Also I don’t have any miss fires and the car runs well except for the idle problem.

M3 hacker · 10-05-2021, 04:13 AM

Quote:

Originally Posted by Fezza

Can also get Alex to send you a 95 RON tune. Had issues with 98 as well until I changed over to Mobil branded 98 fuels from 7-11 and Costco.

Thanks Fezza - I actually haven’t tried Mobil. Do you use Alex’s 95 or 98 RON tune? I haven’t ever heard my car pinging or detonating…

I did notice today when the idle starts fluctuating after idling for 30 seconds the voltage starts fluctuating as well - maybe it’s the voltage regulator?

Fezza · 10-05-2021, 07:47 PM

I use Alex's 98 RON tune. cheapest and easiest thing to try is to fill up with Mobil brand from 7-11 or Costco (if you have their membership) next time. another thing I changed was spark plugs on my car, so can't remember if it was the fuel brand change or spark plugs or both that sorted out my issues. I now plan on changing spark plugs every 3 years or so (I do less than 5k a year).

E90M3_Guy · 10-07-2021, 06:50 AM

Agree that Australia has relatively low quality fuel. Many years ago at the time oil companies released 98 octane fuel in Australia, I had a car with a high compression engine. It ran beautifully on BP or Mobil but the engine would ping and rattle with Shell 98. I concluded Shell was inferior. Ever since, I've used only BP or Mobil (now 7-Eleven).

Never use fuel from anyone other than the major brands.

10-04-2021, 08:19 PM	#1
M3 hacker Private 71 Rep 98 Posts Drives: M3 e92 Join Date: May 2019 Location: Canberra Australia iTrader: (0)	98 octane fuel Has anyone experienced idle problems (fluctuation) when using 98 octane fuels? I have tried different fuel brands and all of them are the same. My car is idling badly and doesn’t have any fault codes. I’ve changed the breather valve, idle control valve and fuel cap with no luck. I can vaguely remember reading somewhere that in Australia using 95 octane fix their problem and it was actually better? I’ve got an Alpine stage 2 98 tune and a bit hesitant using 95. Thanks for any help in advance… Steve Last edited by M3 hacker; 10-04-2021 at 09:11 PM..
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10-04-2021, 09:32 PM	#2
HiFi Lieutenant 418 Rep 505 Posts Drives: 2023 BMW M3 Join Date: Mar 2015 Location: Australia iTrader: (0)	i believe the Alpine 98 tune is too agressive for our low quality fuel. our 98 isnt the same as US 98(93 RON). You might want to get an alpine tune for 95 instead, and keep running 98 fuel. BP is geernally the best. __________________ 2023 G80 M3 www.instagram.com/modern.classica
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10-04-2021, 11:40 PM	#3
ABC99G Private First Class 16 Rep 192 Posts Drives: 2008 E92 M3 Coupe Join Date: Jun 2007 Location: Port Macquarie iTrader: (2)	You could try replacing the spark plugs.
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10-05-2021, 03:07 AM	#4
Fezza Second Lieutenant 149 Rep 254 Posts Drives: '11 Japan Red E92 M3 Join Date: Jan 2019 Location: Perth, Western Australia iTrader: (0)	Can also get Alex to send you a 95 RON tune. Had issues with 98 as well until I changed over to Mobil branded 98 fuels from 7-11 and Costco.
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10-05-2021, 07:47 PM	#7
Fezza Second Lieutenant 149 Rep 254 Posts Drives: '11 Japan Red E92 M3 Join Date: Jan 2019 Location: Perth, Western Australia iTrader: (0)	I use Alex's 98 RON tune. cheapest and easiest thing to try is to fill up with Mobil brand from 7-11 or Costco (if you have their membership) next time. another thing I changed was spark plugs on my car, so can't remember if it was the fuel brand change or spark plugs or both that sorted out my issues. I now plan on changing spark plugs every 3 years or so (I do less than 5k a year).
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10-07-2021, 06:50 AM	#8
E90M3_Guy Private 14 Rep 72 Posts Drives: M3 E90 6MT ZCP LCI 2011 Join Date: Dec 2018 Location: Melbourne, Australia iTrader: (0)	Agree that Australia has relatively low quality fuel. Many years ago at the time oil companies released 98 octane fuel in Australia, I had a car with a high compression engine. It ran beautifully on BP or Mobil but the engine would ping and rattle with Shell 98. I concluded Shell was inferior. Ever since, I've used only BP or Mobil (now 7-Eleven). Never use fuel from anyone other than the major brands.
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