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Accidentally Purchased an E85 Vehicle

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Wow, that is a big handicap for flex vehicle with virtual gas sensor. Every good software design should reset upon losing power and have ability to reprogram correctly.  The acronym LT FT = long term fuel trim and ST LT = short term, right? The software logic as you describe will sooner or later wind down ethanol mpg. The real world events would eventually punish the operator for using ethanol blended fuel. The logic of the controller is biased to eventually make ethanol fuel a problem. I can’t understand how our modern technology would allow such? It can’t be that difficult to learn proper ethanol content, even from reset.

 

So, when you need to change flex cars battery…..better fuel up several times on regular fuel. Maybe high test with no ethanol? And completely warm up car, change battery, then operate the car so as the engine controller can reprogram with pure unleaded as the system has no built in logic to determine ethanol from the reset. 

 

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I have never seen more than a minor stumble for a few secs when removing my conversion so the ecu saw a drastic change in e%. Short term trim can quickly adapt. I think this was a bigger problem for older, narrow band engines.

 

Exactly you don't have a FFV and here we are talking about a factory FFV, in particular one that uses a VFCS algorithm.

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Wow, that is a big handicap for flex vehicle with virtual gas sensor. Every good software design should reset upon losing power and have ability to reprogram correctly.  The acronym LT FT = long term fuel trim and ST LT = short term, right? The software logic as you describe will sooner or later wind down ethanol mpg. The real world events would eventually punish the operator for using ethanol blended fuel. The logic of the controller is biased to eventually make ethanol fuel a problem. I can’t understand how our modern technology would allow such? It can’t be that difficult to learn proper ethanol content, even from reset.

 

So, when you need to change flex cars battery…..better fuel up several times on regular fuel. Maybe high test with no ethanol? And completely warm up car, change battery, then operate the car so as the engine controller can reprogram with pure unleaded as the system has no built in logic to determine ethanol from the reset. 

 

 

Unfortunately that is the way it is now. W/o a actual FCS present there is no way for the computer to know if the deviation from the base program is from E%, dirty injectors, how the tolerances stacked up on that particular engine, or a combo of all three. So they have it set to reset to a learned E% of E0. There really just isn't any way around it.

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:rstar: This is a really good discussion, folks. 

 

I don't want you all to think I'm laying out on it, I'm just learning what questions to ask my 100 yr old Service Adviser in a few thousand miles.

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My son's 2001 S10 FFV just had a battery fail after 9 years ;D (good Delco battery eh?) and I will know tomorrow how that goes because it had E85 in it. However- this truck has the real FCS sensor in it so I do not anticipate any problems. My scan tool cannot feed back into the ECU and since it has the FCS I did not even bother.

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