Flex Fuel Spark Not Following Commanded....

[edmundu]

Hi,

I just recently installed and started tuning for flex fuel on my c6Z06. I thought I understood the multiplier settings within the Mult vs Comp table. But apparently I must be doing something wrong...as from what I have set I was expecting only 20% or so of the values in the spark adder table, not the near 50%! The alcohol % read by the sensor was 45%. I have attached pics of my MultvsComp,Flex Spark, and my flex spark log. Was hoping someone here may help me see what is happening. Or maybe there is another table that is influencing?

MultvsComp.pngFlexSpark.pngFlexSparkLog.png

[Higgs Boson]

There are other multiplier tables, you should create a Spark Config file and log everything you can for spark.

Also, you might want to pull timing rather than add it at cruise/low load values and add it in high load/wot values....look at other flex fuel oem tunes. E85 requires less timing at low load but can handle more at high load.

[edmundu]

Thanks for the suggestion....What other tables multiply FlexSpark? I understand timing advance having multiple tables, but not the flex spark...

I had removed a bunch of timing out of the HO table, so figured I could add a little back in with the E85 mix. I will not tune for max power until I put it on the dyno, as I realize that I will likely not encounter knock before hitting MBT. This was more for being able to see that the flex fuel tables were adjusting as expected.

[DSteck]

That multiplier table is for the PE adder. It's not for flex fuel spark.

[edmundu]

Do you know what the right table is? The description on the table from HPTuners stated it was for PE/COT and Flex Spark...

[edmundu]

The only other table I saw that looked like it might be it was named Alcohol Mult?

[rio95]

Did u figure this out? Everything I'm reading says that multiplier table IS for flex spark. Seems that's what most people are using.

[GHuggins]

multiplier vs composition is what your after... it will multiply out for flex spark before it will the pe table depending on controller... really need to have all tables populated instead of just one for best all around flex tune...

[rio95]

After testing today I did find that the mult table controls flex spark just fine so I don't know why Dave said that.

[LSxpwrdZ]

Iirc the alcohol percent axis isn't correct for that table. I want to say it's more like 0, 10, 20, 50, 80

[rio95]

Iirc the alcohol percent axis isn't correct for that table. I want to say it's more like 0, 10, 20, 50, 80

So you're saying if you have a multipler of 1 in the last two cells the multiplier gets multiplied by 50% and 80% respectively? I have 1 in the last two cells and it's adding all the timing in my flex spark table at 75% content, which is what I think it should do.

[LSxpwrdZ]

So you're saying if you have a multipler of 1 in the last two cells the multiplier gets multiplied by 50% and 80% respectively? I have 1 in the last two cells and it's adding all the timing in my flex spark table at 75% content, which is what I think it should do.

Yes that is correct. Instead of it being 0, 25, 50, 75, 100 it is 0, 10, 20, 50, 80. At least the other software has this table labeled that way. Makes sense to me too because I've seen similar occurrences tuning flex equipped cars.

[GHuggins]

Yes that is correct. Instead of it being 0, 25, 50, 75, 100 it is 0, 10, 20, 50, 80. At least the other software has this table labeled that way. Makes sense to me too because I've seen similar occurrences tuning flex equipped cars.

I wonder if it's just not right for all the different operating systems out there? I only say this because for the most part the 0, 25, 50, 75 and 100 percents seem to be spot on for the majority of the one's I've done...

[sevinn]

The corrected column headings make much more sense to me. I always just assumed it wasn't a linear interpolation between the columns, but 0,10,20.50,80 labels are more in line with what my car does. Thanks for pointing that out.