You should ask the mail-order tuners if they can tune for E-85 (if its even needed).

 

it is needed to tune for the e-85. you need to add a little more timing and also bump up duty cycle by about 20%

 

I should search for this but since you guys are discussing...

So from what your saying If I fill my empty tank with E85... start it up... will I simply get a lean running motor and therefore lean Lterms? By increasing the duty cycle ~20% will this basically return the Lterms to "normal"? This also should mean the 02's will report Lean with the E85 initially until fuel corrections are made? If this is true Im thinking on production they simply switch to a second (E85) fuel trim table when the 02's report a large amount of lean upon startup/warmup and wouldnt go closed loop until it decidd which table was closer to "normal"?

Im just trying to understand how the PCM knows E85 is in use on the flex fuel carsa and how the 02's react... makes sense if all that is true.

 

Good question.

 

Here is a very good read about the E-85.

http://www.ls1tech.com/forums/showth...e85+conversion

 

That is very useful info to know. i stopped and put 2.2 Gal. of ethanol in the car yesterday and it runs fine. i thought it would throw a check engine light or something but it didn't. Thats without any tuning at all.

 

The problem with that is, if i ever needed to run on gas only i would have to send them the PCM back.

 

yes but generally if you make this conversion you are doing so for the performance side of E-85 b/c it is a less effecient fuel.

therefore you probably wouldn't get in that situation. its just like building a car on race gas.

 

Flex fuel vehicles have a fuel composition sensor that tells the ECU whether and how much ethanol is present.