Lund FF tune (Winter Gas)

[Bluemustang]

Lund FF tune and winter blend gasoline question-

I've posted before that my air-fuel ratio still will not go back to 14.0 which I understand is the stoichiometric value of E10 gas. It pretty much hovers between 13.3-13.7. Sometimes it goes back to 13 momentarily, sometimes it hits 14 or 14.2 for a split second partial throttle.

When I did use E85, I had pretty much air fuel ratio of 10. Lund has checked over my tune awhile back and E85 and 93 octane was good. Fuel trims were good.

But I am still slightly concerned that my AFR won't go back up. Now I think that perhaps the winter blend of gas is what is making my AFR less than 14.0

Is there more ethanol or other additives in winter gas that could be causing this? Anyone have knock on regular 93 octane tunes during the winter time?

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[moffetts]

Do you have an ngauge? There is a metric that shows your alcohol content. Right now I am showing about 34% alcohol (still running some E85 through) and my AFR is roughly 12.

 

[Bluemustang]

Do you have an ngauge? There is a metric that shows your alcohol content. Right now I am showing about 34% alcohol (still running some E85 through) and my AFR is roughly 12.

No I'm on SCT X4. I think LiveLink has a parameter for ethanol content but don't know if it works or is accurate.

And when I say AFR, I mean the reading on the dash gauge.

 

[Sasuketr]

I was also tuned by Lund in summer but my AFR is not going that low on idle. Have you tried filling up with 93 octane ( BP or Shell), disconnecting the battery terminals for overnight and then running the car?

 

[Bluemustang]

I was also tuned by Lund in summer but my AFR is not going that low on idle. Have you tried filling up with 93 octane ( BP or Shell), disconnecting the battery terminals for overnight and then running the car?

No, not yet but I fail to see why that is necessary. If the flex fuel logic works and the sensors work, then it should adjust accordingly without any fuss.

It could also be that I have a small amount of E85 still in there but I doubt it. I've filled up with 93 many times now since I was running the E85. So if it has learned to E15 or E20 and the gas is in fact E10 as the pump states, then tune is not working or my sensors are fouled up. And I will know that I am running rich.

I don't want to have to disconnect the battery just to get the fuel correction right. But I may try just to see.

 

[Bluemustang]

I was also tuned by Lund in summer but my AFR is not going that low on idle. Have you tried filling up with 93 octane ( BP or Shell), disconnecting the battery terminals for overnight and then running the car?

I use shell gas almost exclusively or Sunoco.

 

[Jay-rod427]

After two tanks of 91 around here i still show 18% alcohol, and afr of about 13.7-13.9 so winter blends may contain more than the supposed 15% max.

 

[HISSMAN]

I've still not wrapped my head around how the double tanks work on these cars, but it could be that one side still has mostly E85 ( or whatever FF you filled up with). So it could take you running both sides completely dry to get it down to E10.

 

[Bluemustang]

It's funny I started this thread just now because I started the car this morning (didn't change anything) and the AFR went up. I was idling at 14 again. AFR still fluctuating wildly while driving the car still warming up. It would jump from 11 to 15 and back and forth. And it would eventually settle down at about 13.8-14.2 at idle.

I wonder if my MAF readings or my sensors are off, causing the ECU to overcorrect.

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