Problem trying to enter negative timing values

User topics relating to software that provides a tuning UI to alter ECU code and data

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Problem trying to enter negative timing values

Postby thejean » Thu Sep 14, 2006 6:48 pm

When I try to enter negative timing values in ecuedit, they will not save as negative but automatically turn into some positive number. Anyone know why or to fix this? The allowable value ranges are WELL outside the values I am looking at using. Enginuity will allow negative timing up to -20 degrees but the tables I need are not available in enginuity but rather, are in ecuedit so I need to be able to do it there. Can anyone help?
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Postby Tea cups » Thu Sep 14, 2006 7:47 pm

When you hit a minimum or maximum, that is because you have reached the minimum or maximum value as represented on the ecu. So, for example, a 1-byte data size, that would be 0x00(min) 0xFF(max) and a 2-byte it would be 0x0000(min) and 0xFFFF(max). Whether you can represent a negative number depends on the conversion formula which is based on the original range intended by Subaru (assuming the conversion is correct). So, it is very possible that the table in question may not allow you enter negative timing numbers, but other tables would.
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Postby thejean » Thu Sep 14, 2006 10:25 pm

Yeah, but the same table in Enginuity (the main ign map) allows -20 degrees and that exact same table in ecuedit will only allow 0. I'm confused as to why? :?
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Postby swifty » Fri Sep 15, 2006 2:03 am

I'm confused as to why you would want to enter a negative value in the ignition table.
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Postby Tea cups » Fri Sep 15, 2006 5:24 am

thejean wrote:Yeah, but the same table in Enginuity (the main ign map) allows -20 degrees and that exact same table in ecuedit will only allow 0. I'm confused as to why? :?

I just tried editing a main ign map on a 16bit rom with Ecuedit and it did allow for negative values. What ecu revision are you working with? Try xmlwrite for your definitions when working with Ecuedit.
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Postby thejean » Fri Sep 15, 2006 6:12 am

It will allow you to enter but try close the rom and opening it back up. The program sticks in some positive value that it decides.
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Postby Tea cups » Fri Sep 15, 2006 6:35 am

Just tried it (main ign map). The negative value I entered remains. Are you saving the rom before opening it back up again?
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Postby thejean » Fri Sep 15, 2006 8:49 am

Tea cups wrote:Just tried it (main ign map). The negative value I entered remains. Are you saving the rom before opening it back up again?


Yep, tried that as well. Must be an issue with my XML... Can you show me a portion of your XML that controls this so I can see if mine matches?

Coule it be an issue with the ecuedit version?

Also see for a sample of my XML: http://www.epifansoft.com/phpBB2/viewtopic.php?t=31
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Postby Freon » Fri Sep 15, 2006 1:14 pm

Post your ROM, XML, and tell us exactly what map(s) are having the problem.

I tried opening a few ROMs and putting negative timing numbers in. Seems to work in the latest Ecuedit. Tried both older 16bit and new 32bit roms.

16bit and 32bit ecus both store timing in 8bit. That's -20 to +69.65 BTDC from raw values of 0 to 255, respectively.

Probably an XML screwup. Where did you get your XML? Maybe regenerate it for your ECU by either reinstalling the app or rerunning xmlwrite?
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Postby thejean » Fri Sep 15, 2006 1:36 pm

AHA! It was because I was trying to go to -30... it will in fact accept -20. Although I would prefer -30, -20 will suffice. Thanks fellas!
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Postby Hobbes » Fri Sep 15, 2006 1:50 pm

swifty wrote:I'm confused as to why you would want to enter a negative value in the ignition table.


I would like to understand this too.

Hobbes
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Postby Freon » Fri Sep 15, 2006 2:18 pm

I suppose if you had enough load at low enough RPM you could need negative numbers. From the EVO maps I've seen they have negative numbers. Whether or not they actually hit the cells in the map is another question.
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Postby thejean » Fri Sep 15, 2006 2:27 pm

Hobbes wrote:
swifty wrote:I'm confused as to why you would want to enter a negative value in the ignition table.


I would like to understand this too.

Hobbes


Anti-lag. ;)
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Postby UpPweez » Tue Sep 19, 2006 12:40 pm

Hobbes wrote:
swifty wrote:I'm confused as to why you would want to enter a negative value in the ignition table.


I would like to understand this too.

Hobbes


Many people like to set their dynamic advance table to all one value. The best value is 10 because then when you are looking at your primary ignition it is conceptually very easy and almost intuitive to determine your total ignition advance. Thus, to put 10d in your advance map you must subtract some large amounts from low rpm points. I have -5 in some locations on my map.

Why would you want to make the dynamic advance all the same? Well, I wouldn't say that you would make ALL the dynamic advance the same. However, from 2.0 load and up (STI) it makes sense. You can then review a log file and if you don't see 10d in the Dynamic Advance then you know the ECU wasn't happy. This totally beats trying to remember that you have X degrees at this rpm/load, y degrees at that rpm/load, etc, etc. This makes things very easy. It also adds more protection because you have more dynamic advance and less base advance.
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