Flex tune issue

[Dustind6327]

Ok bare with me while I try to explain my issue, I have an 18 5.0 with flex fuel tune, while I’m on 93 I drive all the way until I’m 20-30 miles to empty. Fill it all the way up with e85 (tested 88 just to make sure it wasn’t junk) afr on 93 is around 14. I drove 2-300 miles to meet up to race and still shows 12.5-13 afr. Why is it taking so long to relearn it’s full of Ethanol?? I remember on my 14 model it would drop to 10 in 5 mins or so, anyone have same issue??

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[AZ18yote]

Ok bare with me while I try to explain my issue, I have an 18 5.0 with flex fuel tune, while I’m on 93 I drive all the way until I’m 20-30 miles to empty. Fill it all the way up with e85 (tested 88 just to make sure it wasn’t junk) afr on 93 is around 14. I drove 2-300 miles to meet up to race and still shows 12.5-13 afr. Why is it taking so long to relearn it’s full of Ethanol?? I remember on my 14 model it would drop to 10 in 5 mins or so, anyone have same issue??

There can be multiple factors other than e content but if you want it to be effective immediately use your handheld to do a KAM reset and it should detect pretty damn quick. Would be surprised if it got anywhere near 5 min.

 

[Bluemustang]

I wonder if your tune is dialed in right for the MAF curve. You should've been 10-11 in AFR. On my 15 if the MAF curve isnt dialed in it won't infer the correct ethanol %. I would presume the 18 cars work in a similar fashion. Assuming an otherwise stock car this would be confusing. Still I would contact your tuner and ask.

 

[Joe 5.0]

I'm having similar issues, except my car isn't learning the proper AFR / Alch % when on 93 octane. For example, when I'm running pure 93 octane, my nGuage shows that I have 23% alcohol in my fuel, even though I've been through multiple tanks of 93. This in turn throws off my AFR, and makes the car run rich. However, I recently filled up with E85, and it seems like everything is OK.

As @Bluemustang said, it may be an issue with our MAF curves. I'm not a tuner so I have no idea what that means. I've mentioned this issue to my tuner, and got nowhere with him.

 

[NastyPumpkin]

Not a fan of flex tunes. It’s best to keep it on one tune E85 or 93.

 

[Bluemustang]

Who's the tuner? The MAF curve is basically the airflow model. If the airflow is miscalculated this will throw off fuel trims and make the computer unable to infer the right ethanol content.

 

[Bluemustang]

I'm having similar issues, except my car isn't learning the proper AFR / Alch % when on 93 octane. For example, when I'm running pure 93 octane, my nGuage shows that I have 23% alcohol in my fuel, even though I've been through multiple tanks of 93. This in turn throws off my AFR, and makes the car run rich. However, I recently filled up with E85, and it seems like everything is OK.

As @Bluemustang said, it may be an issue with our MAF curves. I'm not a tuner so I have no idea what that means. I've mentioned this issue to my tuner, and got nowhere with him.

Sometimes it also takes awhile to relearn when switching back to 93. Likely there was still some E at the bottom of the tank. Sometimes it would take me 3 or 4 full fill ups before all of the E was out of there.

Flex tunes are great, as long as the STFT are within 1-3%. Mine is pretty much spot on.

 

[craigsix]

i would run mine down to 2 or 3 miles to empty and it would go down closer to 10-11 afr faster. usually the second tank would get close to 10.0

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