Tephra v7 9653 thottle hang
Oct 7, 2009, 02:53 PM
#32
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Don't fiddle with the Idle stepper lookup table.
It just makes the rev hang happen at a lower rpm, but it still persists.
The reason why there is rev hang, is there is a table that adds a LOT to your idle demand (the vertical axis on the idle stepper lookup table) and causes the stepper position to go really high.
The tables I used to completely erradicate throttle hang were under the "ISCV Control" category:
- ISCV Demand RPM Adder [rpm > 4500, load > 170, speed > 12 mph]
- ISCV Demand RPM Adder (Moderated by Baro, IATS) (FFFF6EA8) (sub_204B6) [sub_1EFC0]
These two tables add up to 100% on top of your idle demand percentage and makes the lookup value much higher in the idle stepper lookup table.
Zero these two tables out, and log your iscv steps in evoscan.
You'll notice instead of going up to 120 or so when you accelerate hard, the iscv steps will only go up to around 70 instead, which will not induce rev hang. The iscv steps will also decay very quickly, since it won't reach such a high value like before. I haven't noticed any reduction in idle quality or part throttle driveability.
You may have to play with your Decel Fuel Cut Delay tables as well, but I don't know what the difference is between tables 1, 2, 3, and 4 are. I just made all my tables the same values as the ones in table 2 (this one has the lowest values and is the same as table 4).
Sorry for the long explanation, but it kind of makes it hard without pictures!
This post has a wealth of info on how the idle speed control system works.
https://www.evolutionm.net/forums/ec...sassembly.html
Go MrFred you are a legend!
It just makes the rev hang happen at a lower rpm, but it still persists.
The reason why there is rev hang, is there is a table that adds a LOT to your idle demand (the vertical axis on the idle stepper lookup table) and causes the stepper position to go really high.
The tables I used to completely erradicate throttle hang were under the "ISCV Control" category:
- ISCV Demand RPM Adder [rpm > 4500, load > 170, speed > 12 mph]
- ISCV Demand RPM Adder (Moderated by Baro, IATS) (FFFF6EA8) (sub_204B6) [sub_1EFC0]
These two tables add up to 100% on top of your idle demand percentage and makes the lookup value much higher in the idle stepper lookup table.
Zero these two tables out, and log your iscv steps in evoscan.
You'll notice instead of going up to 120 or so when you accelerate hard, the iscv steps will only go up to around 70 instead, which will not induce rev hang. The iscv steps will also decay very quickly, since it won't reach such a high value like before. I haven't noticed any reduction in idle quality or part throttle driveability.
You may have to play with your Decel Fuel Cut Delay tables as well, but I don't know what the difference is between tables 1, 2, 3, and 4 are. I just made all my tables the same values as the ones in table 2 (this one has the lowest values and is the same as table 4).
Sorry for the long explanation, but it kind of makes it hard without pictures!
This post has a wealth of info on how the idle speed control system works.
https://www.evolutionm.net/forums/ec...sassembly.html
Go MrFred you are a legend!
There's two listed together, then farther down is the other one you're looking for.
Oct 7, 2009, 08:52 PM
#34
Just my little addition... I remember reading something about this when the 05's first came out... of course it was for emmisions reasons
Funny thing is that as soon as I switched from to the 0006 rom, the throttle hang seemed to diminish if not disappear completely?? Maybe I screwed something up ha
Funny thing is that as soon as I switched from to the 0006 rom, the throttle hang seemed to diminish if not disappear completely?? Maybe I screwed something up ha
Oct 7, 2009, 11:21 PM
#35
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Heres one for ya, about 1 out of every 20 flashes my car will completely stop the revhang. COMPLETELY, until I need to change something and have to flash it again.
Oct 8, 2009, 04:56 AM
#36
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If anyone can help I have a customer with the 9860014 and it has horrendus throttle hand, actually causing it to hit the rpm limiter and continue boosting when you take your foot off the throttle when driving hard. Its actually quite dangerous.
Apparently it wasn't too bad until it was reflashed by some other firm.
Can anyone provide me with a modified XML / Def file to solve this? I tried playing with the ISC Look up table which made a minor improvement but not to any significance, and the changes only caused it to stall when the air conditioning was turned on.
Apparently it wasn't too bad until it was reflashed by some other firm.
Can anyone provide me with a modified XML / Def file to solve this? I tried playing with the ISC Look up table which made a minor improvement but not to any significance, and the changes only caused it to stall when the air conditioning was turned on.
Oct 8, 2009, 07:03 AM
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^ will test this after work tonight as I am down to 2 issues with my car on 015.
Throttle Hang above 3500 when mid to full throttle (then lifting)
A slight "blurb" when very light throttle (think normal highway driving), then lifting the car "stutters" and goes way rich for a second before returning to 14.7 afr.
Will report back.
BTW
Where could I find those decel fuel cut tables for 88590015 ? I only have 1 table listed in my rom. Thanks
I could swear this is true for me as well but I have flashed so many times hard to keep track..
Oct 8, 2009, 07:15 AM
#38
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<table name="Decel Fuel Cut Delay #1" category="Fuel" address="3d6e" type="2D" level="1" scaling="uint8">
<table name="Engine Load" address="6fc6" type="X Axis" elements="7" scaling="Load"/>
</table>
<table name="Decel Fuel Cut Delay #2" category="Fuel" address="3d82" type="2D" level="1" scaling="uint8">
<table name="Engine Load" address="6fc6" type="X Axis" elements="7" scaling="Load"/>
</table>
<table name="Decel Fuel Cut Retard" category="Fuel" address="3da2" type="2D" level="1" scaling="Timing">
<table name="Engine Speed" address="6b7a" type="X Axis" elements="10" scaling="RPM"/>
</table>
<table name="Fuel Limp Table" category="Fuel" address="31ab" type="3D" level="1" swapxy="true" scaling="uint8">
<table name="TPS" address="6fc6" type="X Axis" elements="7" scaling="Volts16"/>
<table name="Engine Speed" address="6fb2" type="Y Axis" elements="5" scaling="RPM"/>
</table>
Oct 8, 2009, 07:18 AM
#39
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<table name="Decel Fuel Cut Delay #1" category="Fuel" address="3d6e" type="2D" level="1" scaling="uint8">
<table name="Engine Load" address="6fc6" type="X Axis" elements="7" scaling="Load"/>
</table>
<table name="Decel Fuel Cut Delay #2" category="Fuel" address="3d82" type="2D" level="1" scaling="uint8">
<table name="Engine Load" address="6fc6" type="X Axis" elements="7" scaling="Load"/>
</table>
<table name="Decel Fuel Cut Retard" category="Fuel" address="3da2" type="2D" level="1" scaling="Timing">
<table name="Engine Speed" address="6b7a" type="X Axis" elements="10" scaling="RPM"/>
</table>
<table name="Fuel Limp Table" category="Fuel" address="31ab" type="3D" level="1" swapxy="true" scaling="uint8">
<table name="TPS" address="6fc6" type="X Axis" elements="7" scaling="Volts16"/>
<table name="Engine Speed" address="6fb2" type="Y Axis" elements="5" scaling="RPM"/>
</table>
<table name="Engine Load" address="6fc6" type="X Axis" elements="7" scaling="Load"/>
</table>
<table name="Decel Fuel Cut Delay #2" category="Fuel" address="3d82" type="2D" level="1" scaling="uint8">
<table name="Engine Load" address="6fc6" type="X Axis" elements="7" scaling="Load"/>
</table>
<table name="Decel Fuel Cut Retard" category="Fuel" address="3da2" type="2D" level="1" scaling="Timing">
<table name="Engine Speed" address="6b7a" type="X Axis" elements="10" scaling="RPM"/>
</table>
<table name="Fuel Limp Table" category="Fuel" address="31ab" type="3D" level="1" swapxy="true" scaling="uint8">
<table name="TPS" address="6fc6" type="X Axis" elements="7" scaling="Volts16"/>
<table name="Engine Speed" address="6fb2" type="Y Axis" elements="5" scaling="RPM"/>
</table>
