Flex Fuel: How to Guide - Who wants to see it?

[TunedByNishan]

Hello all,

I've worked on enough Copperhead PCM equipped vehicles implementing the inferred Flex Fuel Logic on several of them with great success and I've helped other tuners set up their tunes appropriately for Flex Fuel.

This community and it's members have helped me quite a few times when I was in a pickle and needed assistance tackling unexpected tuning issues and I'd like to give it back somehow so that others can also be helped.

How many people would like to see a walk through guide (with images) on how to properly set up the Ford Inferred Flex Fuel Logic?

This would take me some time to write up as well as sort out a multitude of table screenshots but I am happy to do it if there are many people who are completely lost on the topic.

This would be rather generalized explaining how each control table works but with the addition of showing my own examples of table structures.

It will be up to you to make the appropriate changes to your tune file as YOUR specific vehicle setup requires.

[AKDMB]

I wouldn't mind seeing this, I am kinda confused on the High/Low AFR endpoints and High/Low AFR Range. Eric posted a 2014 F150 Flex Fuel Tune (a factory Flex Fuel vehicle), seeing how it was populated helped out quite a bit. I'm not tuning for Flex Fuel, I am just curious and would like to better know how it worked. It would interesting to see too if the cold enrich decay, base flex fuel or the cranking fuel needed any adjustment. Your call, I don't NEED to see it by any means, thanks for even considering doing this.

[TunedByNishan]

I wouldn't mind seeing this, I am kinda confused on the High/Low AFR endpoints and High/Low AFR Range. Eric posted a 2014 F150 Flex Fuel Tune (a factory Flex Fuel vehicle), seeing how it was populated helped out quite a bit. I'm not tuning for Flex Fuel, I am just curious and would like to better know how it worked. It would interesting to see too if the cold enrich decay, base flex fuel or the cranking fuel needed any adjustment. Your call, I don't NEED to see it by any means, thanks for even considering doing this.

In my opinion, the way Ford structured the Flex Fuel tables for Flex Fuel Equipped vehicles isn't 100% ideal.

It works, but not as "effectively" as I would want a vehicle that I tuned to.

I can explain the end points as well.

[rhinogt]

That would be pretty nifty. I'm currently running flex but I'm always curious to see how others do things.

[Higgs Boson]

Everything seems self explanatory except the Spark blend table since there is no Ethanol Spark Modifier table so what is it blending.

[Jn2]

I'd be interested to see it. I copied the Flex fuel stuff from the 2014 F150 and adjusted some of the WOT tables but am curious to see what else can be done.

[esacteksab]

Definitely interested!

[tramotorsports]

I'd give it a read for sure. Love reading.

[thegraystang]

Nishan helped me out the other night and i implemented it and it works on the money. it really is simple. the 15+ i believe are short a table so i think its even easier. the endpoint/range is the only somewhat confusing part. Pretty cool turning not he logic and filling up with X amount of eth and watching the AFR go to what it should be per the blend.

[LavaRed50]

that would definitely be nice to have in the forums

[SultanHassanMasTuning]

wish we could take advantage of Ethanol, but its never gonna happen

[kris5597]

The issue I keep running into with my flex fuel tune is that every time I fill up with e85, if percentage is 70% or higher, the car will read it at 100% ethanol. But then if I reflash the ECU, it compensates correctly and reads the correct amount of ethanol content.

Kris

[Jn2]

The issue I keep running into with my flex fuel tune is that every time I fill up with e85, if percentage is 70% or higher, the car will read it at 100% ethanol. But then if I reflash the ECU, it compensates correctly and reads the correct amount of ethanol content.

Kris

That is weird. What do you under

Engine>Fuel>Open and Closed Loop>"Flex Fuel Ethanol % vs AFR"

That is the table where you can set the Ethanol percentage. Here is how mine is set up, I havent tried adding more values on the x axis yet though, but I would assume it's scaled based on this table. So if you wanted it to be more accurate you could change the X values and set the appropriate AF's for it.

[kris5597]

That is weird. What do you under

Engine>Fuel>Open and Closed Loop>"Flex Fuel Ethanol % vs AFR"

That is the table where you can set the Ethanol percentage. Here is how mine is set up, I havent tried adding more values on the x axis yet though, but I would assume it's scaled based on this table. So if you wanted it to be more accurate you could change the X values and set the appropriate AF's for it.

That's how its setup on the f150 and the way mine originally was. I scaled mine this way, wouldn't think it would make it cause a problem, figured it would make it more accurate. But I could definitely be wrong.

[Higgs Boson]

You probably arent going to have over E85 or under E10 (unless you know for a fact you have E0 at your pump)

set my axis to 9.85 at the top and 14.08 at the bottom and interpolate
set the table to 85 at the top and 10 at the bottom and interpolate
set my Max and Min and lock values to the same 9.85 for both and 14.1 for both
initial stoich is 14.08

my flex stuff works perfectly, just not sure if we aren't missing a spark table.

[thegraystang]

I'm fairly confident my fuel side is working. Pretty sure the station is still on shitty winter blend. Spark seems not to be doing its thing. It should be adding 2 degrees extra and I'm not seeing it. I've compared logs when I did an initial 5 gallon mix and then 12 gallons and timing is the same on both. Fuel adjusted but spark doesn't seem to be.

[Higgs Boson]

How have you set up your retard tab?

[thegraystang]

not sure what youre asking but ill just post the file. site wont let me load the x4 log.

[Higgs Boson]

when and where do you think it should be "adding two degrees?"

[Witt]

I'm fairly confident my fuel side is working. Pretty sure the station is still on shitty winter blend. Spark seems not to be doing its thing. It should be adding 2 degrees extra and I'm not seeing it. I've compared logs when I did an initial 5 gallon mix and then 12 gallons and timing is the same on both. Fuel adjusted but spark doesn't seem to be.

One of the bigger name SCT tuners mentioned on a forum somewhere that the spark side of the flex fuel logic isn't complete in a lot of the Copperhead Mustang PCMs.