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Old 12-05-2007, 02:49 PM   #1
dynamix
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Default Strange 24 deg of advance on deceleration

I have been using Enginuity to modify my ecu rom on my 2.5 EDM STi 2006

When logging deceleration it shows up a base ignition timing value of 24 degrees. This is when load is around 0.22 and running down through the revs to about 3500rpm.

There is a table in the ECUflash software / xml defs that open this as Base Ignition Timing A but is only a 2 x 2 table.

For 1200 rpm and 0.25 load this shows as 21 ish deg
There is a flat 3.16 deg value in the Enginuity table Timing Compensation B (intake Temp)

Would this be where this value is coming from?

I am wanting to reduce timing in these loads cells right down to a low value - but wanted to know why it is adding it in there to start with.

Any ideas?

update:

I have amended the ml to include that table in enginuity and reflashed it back on but still giving the 24 deg min advance on deceleration.

Any idea where this base level is set ?

I am wanting 5 deg of advance in the .25 load column ....
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Old 12-05-2007, 04:01 PM   #2
Tea cups
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The timing compensation tables (such as IAT B) will not appear in base timing, if you are logging 'ignition base timing*' the extended parameter in Enginuity's logger and not the standard 'ignition timing' which is total timing. I seriously doubt that the 2x2 base timing table is used. I removed these types of tables from the definitions a while back as I began to notice that this is generally Subaru/Denso's method of indicating that a table has been removed from consideration - meaning that some other model or year may use switching logic (say the non-USDM LGTs that have the old school SI-drive). So, rather than recode the entire routine for model that doesn't use it, they simply leave it the same but manipulate the map ratio multiplier to always be one value (so only one of the tables is used for example) and resize the "appendix" map. Anyway, there are quite a few elements to timing that still need to investigated. Likely this is one of them. If you want to figure this out, I can send you some custom logger defs to try to isolate the issue (and rule in or out the 2x2 table as well). Just PM me your rom id on the OpenECU site.
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Old 12-05-2007, 05:41 PM   #3
dynamix
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pm sent - I presume you are Tea Cups there too ... else someone will have a rather random pm
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Old 12-06-2007, 01:07 AM   #4
mickeyd2005
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2005 LGT Wagon
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If your foot is off the accelerator and the car is overruning (such as decelerating), the timing appears to come from another table. On my LGT, it is 19 degrees.

The Timing Compensation Intake B table on the 2005 LGT is a constant 3.16 degrees as well. It seems odd that this is considered a temperature compensation since it is constant relative to temperature. One of the problems with this table is that on the 2005 LGT, it cuts off rather suddenly between 3000 and 3500 rpm depending upon load. I changed it to 0 and then tuned base timing without it.

BTW, for anyone who hasn't figured it out, Tea Cups is merchgod on enginuity.
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Old 12-06-2007, 06:59 AM   #5
Tea cups
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Quote:
Originally Posted by mickeyd2005 View Post
The Timing Compensation Intake B table on the 2005 LGT is a constant 3.16 degrees as well. It seems odd that this is considered a temperature compensation since it is constant relative to temperature.
It isn't the same with all ROMs.
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Old 12-06-2007, 12:00 PM   #6
mickeyd2005
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Quote:
Originally Posted by Tea cups View Post
It isn't the same with all ROMs.
Yeah, I can only speak for my own rom.

In other roms, does it still cut out rapidly? On the LGT, regardless of whether it is 3.16 or 1.05 or even if it is not constant vs temperature, it cuts out in 1 time step. It makes it very difficult to tune the timing.

I'ld like to understand the logic more, but (IIRC) the STi doesn't have this step in their timing curves at 3000-3500 rpm so I went ahead and got rid of it for my LGT. Not sure if that was the right thing to do, but it seems to work for me.
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Old 12-06-2007, 12:15 PM   #7
dynamix
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I am trying to put a base 5 degree of advance in the 0.25 load column for above 3200 rpm.

This is for two reasons:

1) to provide some sound effects on deceleration
2) to retard the ignition in a sort of ghetto anti-lag system to help spool up between gear changes

It will drop down to the 5 degrees if the throttle is pressed ever so slightly. But if on a full trailing throttle, is throws in this 24 degree of timing as a flat figure.

This seems to be independent of coolant or air intake temperatures.

This 24 degrees must be in a table somewhere within the rom.

I am wondering whether putting in a small value in the requested torque table for 0% throttle will get around this ... as a make shift solution ??
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Old 12-06-2007, 12:57 PM   #8
Tea cups
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Quote:
Originally Posted by mickeyd2005 View Post
Yeah, I can only speak for my own rom.

In other roms, does it still cut out rapidly? On the LGT, regardless of whether it is 3.16 or 1.05 or even if it is not constant vs temperature, it cuts out in 1 time step. It makes it very difficult to tune the timing.

I'ld like to understand the logic more, but (IIRC) the STi doesn't have this step in their timing curves at 3000-3500 rpm so I went ahead and got rid of it for my LGT. Not sure if that was the right thing to do, but it seems to work for me.
Here's some more details about how the table works for the 06 WRX (I didn't check the LGTs to see if the thresholds were different):
http://forums.nasioc.com/forums/show...0&postcount=36

I would go ahead and eliminate the compensation. I'm guessing it is strictly an emissions thing.
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