Ethanol Content Sensor - Always at 11%?

[TurboTapin]

Quick question for you fine folks who see more ethanol in your tanks. I installed my ethanol content sensor last year. It reads temperature fine and at the time was reading 11% which I found normal for our E10 fuel over here. Issue is, since last year, I've never once seen it read anything but 11%. 

I always use the same gas, from the same gas station so I was telling myself it was normal... but I'm starting to have doubts. I would have expected to see some sort of variation by now. Unfortunately, it's not as easy as just trying another pump as the 94AKI (~100RON) fuel I run is only offered by one retailer.

[Kinkstaah]

Yes mine will scale from 0.1% to 100%.

It is feasible that the retailer does have a strict adherence to the formula..

[Murray_Calavera]

Makes sense that e10 is e10. 

Sure if it's e85 and winter, drop the e content to aid cold starts but at only 10% ethanol content, there is no reason to change the formula. 

Is there any e85 in your area?

[GTSBoy]

Just do an experiment. Run the tank down to nearly empty. Put 20L of something else in it, with no ethanol. Swish it round with the pump (ie running at idle and/or low load). Then fill it up with the decent stuff and drive sensibly for a half tank then fill it properly. Or suck the crap out and put it in the wife's car. Whatever.

[Duncan]

7 hours ago, GTSBoy said:

Just do an experiment. Run the tank down to nearly empty. Put 20L of something else in it, with no ethanol. Swish it round with the pump (ie running at idle and/or low load). Then fill it up with the decent stuff and drive sensibly for a half tank then fill it properly. Or suck the crap out and put it in the wife's car. Whatever.

I was going to say the wife's lawnmower, but same concept

[Kinkstaah]

I think you'll find that all fuel in some countries has 10% ethanol in it.

[GTSBoy]

The opposite experiment is equally viable. 10L of petrol in the tank + 2L of metho.

[MBS206]

10 hours ago, GTSBoy said:

The opposite experiment is equally viable. 10L of petrol in the tank + 2L of metho.

Couple of litres of moonshine from his southern cousins would do it...

[GTSBoy]

4 hours ago, MBS206 said:

Couple of litres of moonshine from his southern cousins would do it...

You say potato, I say potato?

[joshuaho96]

E10 is pretty tightly regulated in percentage. Too much and engines can't adapt. Every incentive is against them to have too little ethanol though. The more ethanol the higher the octane.

[Dose Pipe Sutututu]

Pour in the highest octane, non-ethanol fuel you can get and see if the readout changes.

If it's dead bang on 11% then I would question the sensor. Another quick test, just take it out and run normal (in an american accent) gas-o-line through it and see if the sampled ethanol or lack of changes.

 

United E85 here in the land of drop bears does vary a bit, I've had as high as E87 (could be water in their tanks too, who knows)

[TurboTapin]

Thanks everyone for the responses. Our fuel in Quebec is all E10 by law. We do not have any other options. I know in the US, E85 has a wide tolerance (~51-85%) and I had presumed E10 would also have a slight tolerance but to some peoples point... if it's regulated by law then more effort must be put in to keep it at 10%.

I'm thinking I'm just going to remove my sensor, cap an end and fill it with different fuels I have in the shed for my lawn tractor, power toys, etc. They are all lower octane and from different vendors. I'm presuming if I still see no variance from 11% after that, then I can conclude the sensor is no bueno. 

 

On 14/07/2025 at 7:34 AM, Kinkstaah said:

Yes mine will scale from 0.1% to 100%.

It is feasible that the retailer does have a strict adherence to the formula..

Your sensor reads down to .1%'s? I recall mine only reading 0-100%. I'll check in my ecu tonight in case I didn't scale it properly.

[Murray_Calavera]

10 minutes ago, TurboTapin said:

Our fuel in Quebec is all E10 by law

I have to ask, if all your fuel is the same, why did you buy and install a flex sensor? 

I'm so confused, what do you use the flex sensor calibration tables for? 

[Dose Pipe Sutututu]

Maybe for when he's feeling rich and buys E85 drums

[TurboTapin]

8 minutes ago, Murray_Calavera said:

I have to ask, if all your fuel is the same, why did you buy and install a flex sensor? 

I'm so confused, what do you use the flex sensor calibration tables for? 

Haha fair question. For two reasons.

1. Once I'm done migrating my water/methanol system over from pre-TB to direct port, I'll be hitting the dyno again. I also plan on trying Ignite E98 race fuel at the same time. I could not be bothered with emptying the tank every time, so anything between E70-E98 I'll be happy with. "Race" fuels are very expensive vs pump E85, so if I grow annoyed of paying, I may also just cross the border to fill a barrel and keep it in the garage. 

2. Quebec is slowly increasing all pump fuels from E10 -> E15 by 2030. My daily fuel is 100RON + Water/Methanol and this will have an impact over the years. 

[Kinkstaah]

36 minutes ago, TurboTapin said:

Thanks everyone for the responses. Our fuel in Quebec is all E10 by law. We do not have any other options. I know in the US, E85 has a wide tolerance (~51-85%) and I had presumed E10 would also have a slight tolerance but to some peoples point... if it's regulated by law then more effort must be put in to keep it at 10%.

I'm thinking I'm just going to remove my sensor, cap an end and fill it with different fuels I have in the shed for my lawn tractor, power toys, etc. They are all lower octane and from different vendors. I'm presuming if I still see no variance from 11% after that, then I can conclude the sensor is no bueno. 

Your sensor reads down to .1%'s? I recall mine only reading 0-100%. I'll check in my ecu tonight in case I didn't scale it properly.

Yea mine does, I assume we all use the same sensor. I'm not sure whether it is exact down to the .1%, but it definitely does have decimal points involved.

[GTSBoy]

Just tip a bottle of metho into a nearly empty tank. You should see that signal.

's'not difficult.

[joshuaho96]

18 hours ago, TurboTapin said:

Thanks everyone for the responses. Our fuel in Quebec is all E10 by law. We do not have any other options. I know in the US, E85 has a wide tolerance (~51-85%) and I had presumed E10 would also have a slight tolerance but to some peoples point... if it's regulated by law then more effort must be put in to keep it at 10%.

I'm thinking I'm just going to remove my sensor, cap an end and fill it with different fuels I have in the shed for my lawn tractor, power toys, etc. They are all lower octane and from different vendors. I'm presuming if I still see no variance from 11% after that, then I can conclude the sensor is no bueno. 

 

Your sensor reads down to .1%'s? I recall mine only reading 0-100%. I'll check in my ecu tonight in case I didn't scale it properly.

In the US almost everything is E10. It can't exceed 10% by much or fuel systems have trouble adapting. At the same time because MTBE, MMT, and TEL are all banned they need as much ethanol in it as possible to boost octane.

[GTSBoy]

And we shall have to presume that Canada is the same?

[Murray_Calavera]

2 hours ago, joshuaho96 said:

In the US almost everything is E10

If I drove to a typical petrol station, what would my choices of fuel be?