XFI FEC timing ?

[NY Twin Turbo]

This doesn't make sense to me.

I do not have a flex fuel sensor, and I have flex fuel enable unchecked, and I have my FEC set to 1.

Yet, if my Timing vs FEC graph is set to increase timing as FEC goes down then the full timing is applied to my tune on top of base timing as if it was reading minimum FEC.

This is dangerous if you play with this graph and forget to zero it out. Even with flex fuel unchecked. That graph should be inactive when flex fuel mode is unchecked especially if there isn't a sensor present to even read!

Anyone notice this on a log? Or was it just me. Good thing I have a safe tune and didn't have a lot of timming on the graph.

Iv'e tested this.

 

[NY Twin Turbo]

Also, after looking through the index, I noticed it said if you don't want any FEC timing applied then zero out the graph. OK, that makes sense to me. What doesn't make sense is that if the map is set to change timing based on FEC but there is no way it can tell (no sensor present) then why does it change?

I can't be the only one who noticed this. Am I? Or do I have something set wrong.

 

[turbo2nr]

ttt

Cal?

 

[NY Twin Turbo]

ttt

Cal?

Oh, finally? Did you notice this too? I posted this question 5 months ago. I thought I was the only person in the country this has happened to.

 

[Lance]

Not sure I understand the issue completely.. If a fuel composition sensor is not present (flex fuel mode unchecked), you can still manually change the FEC to compensate for your fuel type. If you always have a '0' timing offset in the spark vs. FEC table, there should be no unintended consequences.

 

[NY Twin Turbo]

Not sure I understand the issue completely.. If a fuel composition sensor is not present (flex fuel mode unchecked), you can still manually change the FEC to compensate for your fuel type. If you always have a '0' timing offset in the spark vs. FEC table, there should be no unintended consequences.

This was how it was set up.

-In Fuel Calculation Parameters". I had flex fuel mode unchecked.
-In Fuel Calculation Parameters. I had Fuel Energy Constant at 1.000.
-There is no Fuel Compensation Sensor present. (I don't have one!)
-On the Spark Offset vs. Fuel Energy Constant table. I had the line pulled up on a slope from 0 to 3 degrees as FEC numbers dropped from 1.00 to maximum 0.65.

This is what happened. The FAST added 3 degrees to the entire Base Spark Table.

This was in addition to timing also being added for dropping air temps. But this I knew about. Because I add timing when temps drop to take advantage of the alky injection.

However, I could not account for the other 3 degrees. Until I found it on the Spark Offset vs. FEC graph. When I zero'd it out, it went away.

I'll be sure not to play with graphs I'm not using anymore. Even when the option is checked off.

 

[Lance]

Let me ask you this... Did you set up your table so the FEC indices go from left to right as low to high? ..or left to right is high to low? I suspect you have the latter and this is screwing with the lookup which is trying to bracket the vector by scanning left to right. It's only seeing the highest value and using that. Try this: Paste the "Spark Offset vs. FEC Table.ict" into your map then adjust the spark offset to your liking. Leave the indices alone. Let me know. Thanks.

 

[NY Twin Turbo]

Let me ask you this... Did you set up your table so the FEC indices go from left to right as low to high? ..or left to right is high to low? I suspect you have the latter and this is screwing with the lookup which is trying to bracket the vector by scanning left to right. It's only seeing the highest value and using that. Try this: Paste the "Spark Offset vs. FEC Table.ict" into your map then adjust the spark offset to your liking. Leave the indices alone. Let me know. Thanks.

Lance,

My Spark Offset vs. Fuel energy Constant graph is set up from high on the left to low on the right. As follows.......

1.00, 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65

At FEC=1.00 I had no timing increase. Then on a continuous slope to FEC=0.65 I had 3 degrees added. The XFI added 3 degrees to the entire base map even though all other settings were as in my previous post.

I have no intentions to use this map. I was just playing around with a possible scenario and figured it wouldn't take effect anyway due to the other settings not supporting its use. I was wrong. It was applied anyway. This is why I was concerned for others.

 

[Lance]

Lance,

My Spark Offset vs. Fuel energy Constant graph is set up from high on the left to low on the right. As follows.......

1.00, 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65

At FEC=1.00 I had no timing increase. Then on a continuous slope to FEC=0.65 I had 3 degrees added. The XFI added 3 degrees to the entire base map even though all other settings were as in my previous post.

I have no intentions to use this map. I was just playing around with a possible scenario and figured it wouldn't take effect anyway due to the other settings not supporting its use. I was wrong. It was applied anyway. This is why I was concerned for others.

So yeah.... Your indices are backwards. If you change to 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.0, it will work fine. We'll have to get the manual updated to avoid this confusion in the future.

 

[NY Twin Turbo]

Let me ask you this... Did you set up your table so the FEC indices go from left to right as low to high? ..or left to right is high to low? I suspect you have the latter and this is screwing with the lookup which is trying to bracket the vector by scanning left to right. It's only seeing the highest value and using that. Try this: Paste the "Spark Offset vs. FEC Table.ict" into your map then adjust the spark offset to your liking. Leave the indices alone. Let me know. Thanks.

OK. I see it now. This table is set up from left to right as follows.......

0.44, 0.61, 0.68, 0.75, 0.80, 1.00, 1.07, 1.17.
------------------------------------------------------------
So, Let's say I tune for no off-set at 1.00 FEC and then add timing for lower FEC numbers.( As if I was planning to use E-85 but then decided not to.)

1) But I don't have a fuel composition sensor.

2) And I have Flex Fuel Mode unchecked.

3) And I have my Fuel Energy Constant set to 1.000.
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Then the timing won't be modified from the base settings?

If not, Good! But why then did it happen before? Does not having the map set-up properly make the XFI ignore the other 3 things that tell it not to modify my base timing?

I'll try it this weekend. I'm now beginning to question my accuracy recalling what my settings were 6 months ago when this happened. But now the suspense is killing me.

 

[NY Twin Turbo]

No time to try it yet. Maybe tomorrow if it doesn't rain. Anyone else try it?