How to Eliminate "Rev-Hang" on the 05+ EVO 8/9s - EvolutionM - Mitsubishi Lancer and Lancer Evolution Community

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How to Eliminate "Rev-Hang" on the 05+ EVO 8/9s

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Old May 1, 2013, 09:31 AM
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How to Eliminate "Rev-Hang" on the 05+ EVO 8/9s

I get a lot of emails about eliminating the rev hang in the 05+ EVOs. So heres how to fix it.

STEP 1 - Change the "Decel Fuel Cut Delay" tables (aka "ISCV Demand TPS Adder, AC off (FFFF6E84) (mattjin fuel cut delay)" & "ISCV Demand TPS Adder, AC on (FFFF6E84) (mattjin fuel cut delay)"). Use the values show below:

NOTE: When using the "ISCV Demand TPS Adder, AC off (FFFF6E84) (mattjin fuel cut delay)" & "ISCV Demand TPS Adder, AC on (FFFF6E84) (mattjin fuel cut delay)" tables, the values will be different, use the bottom values.




STEP 2 - Zero out all the "ISCV Demand RPM adder" tables.



STEP 3 - Enjoy your car without rev hang

Note: Some of these tables may not be in your current .xml file for your ROM and you may have to add them manually.

DEFINITIONS:

88590015

<table name="Decel Fuel Cut Delay #1" category="Global Fuel Settings" address="3d6e" type="2D" level="2" scaling="uint8">
<table name="Load" address="6fc6" type="X Axis" elements="7" scaling="Load"/>
</table>

<table name="Decel Fuel Cut Delay #2" category="Global Fuel Settings" address="3d82" type="2D" level="2" scaling="uint8">
<table name="Load" address="6fc6" type="X Axis" elements="7" scaling="Load"/>
</table>

<table name="ISCV Demand TPS Adder, AC off (FFFF6E84) (mattjin fuel cut delay)" category="ISCV Control" address="3d6e" type="2D" level="1" scaling="ISCV_AX2_8">
<table name="TPS" address="6f9a" type="Y Axis" elements="7" scaling="ThrottlePercentage"/>
</table>

<table name="ISCV Demand TPS Adder, AC on (FFFF6E84) (mattjin fuel cut delay)" category="ISCV Control" address="3d82" type="2D" level="1" scaling="ISCV_AX2_8">
<table name="TPS" address="6f9a" type="Y Axis" elements="7" scaling="ThrottlePercentage"/>
</table>

<table name="ISCV Demand RPM Adder* (sub_1EFC0)" category="ISCV Control" address="41d8" type="2D" level="2" scaling="ISCV_AX2_8">
<table name="RPM" address="6b7a" type="Y Axis" elements="10" scaling="RPM"/>
</table>

<table name="ISCV Demand RPM Adder [rpm 4500, load 170, speed 12 mph] (sub_1EFC0)" category="ISCV Control" address="65de" type="2D" level="2" scaling="ISCV_AX2_8">
<table name="RPM" address="7fb0" type="Y Axis" elements="10" scaling="RPM"/>
</table>

<table name="ISCV Demand RPM Adder (Moderated by Baro, IATS) (FFFF6EA8) (sub_204B6) [sub_1EFC0]" category="ISCV Control" address="672a" type="2D" level="2" scaling="ISCV_AX2_8">
<table name="RPM" address="802a" type="Y Axis" elements="10" scaling="RPM"/>
</table>

96940011

<table name="Decel Fuel Cut Delay #1" category="Fuel" address="3972" type="2D" level="2" scaling="uint8">
<table name="Load" address="5d52" type="X Axis" elements="7" scaling="Load"/>
</table>

<table name="Decel Fuel Cut Delay #3" category="Fuel" address="3986" type="2D" level="2" scaling="uint8">
<table name="Load" address="5d52" type="X Axis" elements="7" scaling="Load"/>
</table>

<table name="ISCV Demand TPS Adder, AC off (FFFF6E84) (mattjin fuel cut delay)" category="ISCV Control" address="3972" type="2D" level="1" scaling="ISCV_AX2_8">
<table name="TPS" address="5d52" type="Y Axis" elements="7" scaling="ThrottlePercentage"/>
</table>

<table name="ISCV Demand TPS Adder, AC on (FFFF6E84) (mattjin fuel cut delay)" category="ISCV Control" address="3986" type="2D" level="1" scaling="ISCV_AX2_8">
<table name="TPS" address="5d52" type="Y Axis" elements="7" scaling="ThrottlePercentage"/>
</table>

<table name="ISCV Demand RPM Adder* (sub_1EFC0)" category="ISCV Control" type="2D" address="3de4" level="2" scaling="ISCV_AX2_8">
<table name="RPM" type="Y Axis" address="594e" elements="10" scaling="RPM"/>
</table>

<table name="ISCV Demand RPM Adder [rpm 4500, load 170, speed 12 mph] (sub_1EFC0)" category="ISCV Control" type="2D" address="56e0" level="2" scaling="ISCV_AX2_8">
<table name="RPM" type="Y Axis" address="6e92" elements="10" scaling="RPM"/>
</table>

<table name="ISCV Demand RPM Adder (Moderated by Baro, IATS) (FFFF6EA8) (sub_204B6) [sub_1EFC0]" category="ISCV Control" type="2D" address="57f0" level="2" scaling="ISCV_AX2_8">
<table name="RPM" type="Y Axis" address="6ef0" elements="10" scaling="RPM"/>
</table>
Attached Thumbnails How to Eliminate &quot;Rev-Hang&quot; on the 05+ EVO 8/9s-rev-hang-fix2.png   How to Eliminate &quot;Rev-Hang&quot; on the 05+ EVO 8/9s-rev-hang-fix.png  

Last edited by Boosted Tuning; Oct 29, 2015 at 11:07 PM.
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Old May 1, 2013, 10:02 AM
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Old May 1, 2013, 01:59 PM
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for the decel fuel cut delay, which values are we supposed to be switching to? the top or the bottom?

Last edited by JD Ashley; May 1, 2013 at 02:09 PM. Reason: Rephrased question
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Old May 1, 2013, 03:07 PM
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Originally Posted by JD Ashley View Post
for the decel fuel cut delay, which values are we supposed to be switching to? the top or the bottom?
Bottom.
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Old May 1, 2013, 03:27 PM
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That's what I figured, do I need to modify decel fuel cut 3 &4?
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Old May 1, 2013, 03:35 PM
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Originally Posted by JD Ashley View Post
That's what I figured, do I need to modify decel fuel cut 3 &4?
Yeah, just do them the same way. The ones that a lil lower stock, will be the lil lower modified one.
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Old May 2, 2013, 04:26 AM
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just want to point out that :

1) fuel cut delay do not exist, those were wrong definitions, the label is wrong, the load is wrong the units are wrong, why keep using something that has nothing labeled right and with values that represent nothing ?
2) the ISCV demand tables shown in those pictures are also wrong, it should be TPS % on the left not RPM and mrfred who found the real table only attributed 7 elements to it so I'm wondering what are really doing the 3 more shown in the above pictures ?!

Decel fuel cut has originally been guessed by mattjin but has since then been corrected by mrfred
see there in the 1st post : https://www.evolutionm.net/forums/ec...sassembly.html
The address used should be the same as decel fuel cut (double check before changin anything), update the table definition from mrfred thread and you're good.
Code:
<table name="ISCV Demand TPS Adder, AC off (FFFF6E84) (mattjin fuel cut delay)" category="Idle" address="3d6e" type="2D" level="1" scaling="ISCV_AX2_8">
 <table name="TPS" address="6f9a" type="Y Axis" elements="7" scaling="ThrottlePercentage"/>
 </table>

 <table name="ISCV Demand TPS Adder, AC on (FFFF6E84) (mattjin fuel cut delay)" category="Idle" address="3d82" type="2D" level="1" scaling="ISCV_AX2_8">
 <table name="TPS" address="6f9a" type="Y Axis" elements="7" scaling="ThrottlePercentage"/>
 </table>


for your information :

- I also zeroed them because I appreciate the instant engine-braking this change provides
- know that doing that can hide the real problem, if everything was ok you shouldn't have more than a "livable" 1sec of hang
- stock has a small amount of it, it's meant to make gear changes smoother, zeroing those tables can make the car buck every time you lift-off (depends in great part on your recirc/bov)
- ISCV control is very complicated and takes lots of things into account : a/c , power steering, braking, acceleration, temperature etc... a good 100 parameters are taken into account so your throttle hang can come from a lots of things (turn out mine was coming from the steering pump, it blew up one day and after the change my hang was gone and I could drive normally without zeroing those tables)
- log your ISC steps at idle (warm engine) you should have something between 20-40 steps if you have 50+ you have a real problem somewhere

I battled with throttle hang problems for 2 years on my car, I hope you'll fix yours faster than that, good luck !

Last edited by Kakihara; May 2, 2013 at 04:59 AM.
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Old May 2, 2013, 06:33 AM
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Originally Posted by Boosted Tuning View Post
STEP 2 - Zero out all the "ISCV Demand RPM adder" tables.

I'd be careful with zeroing out everything in the low rpm range. This can lead to the car dying while coming off throttle after cruising.

Dan
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Old May 2, 2013, 06:40 AM
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I'm subbing in!!!
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Old May 2, 2013, 11:25 AM
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Originally Posted by Kakihara View Post
just want to point out that :

1) fuel cut delay do not exist, those were wrong definitions, the label is wrong, the load is wrong the units are wrong, why keep using something that has nothing labeled right and with values that represent nothing ?
2) the ISCV demand tables shown in those pictures are also wrong, it should be TPS % on the left not RPM and mrfred who found the real table only attributed 7 elements to it so I'm wondering what are really doing the 3 more shown in the above pictures ?!
All that doesnt matter. Yes the decel fuel tables were defined "wrong" but that doesnt matter. All that matters is that doing this works.

Originally Posted by Kakihara View Post
1 - know that doing that can hide the real problem, if everything was ok you shouldn't have more than a "livable" 1sec of hang
2 - stock has a small amount of it, it's meant to make gear changes smoother, zeroing those tables can make the car buck every time you lift-off (depends in great part on your recirc/bov)
3 - ISCV control is very complicated and takes lots of things into account : a/c , power steering, braking, acceleration, temperature etc... a good 100 parameters are taken into account so your throttle hang can come from a lots of things (turn out mine was coming from the steering pump, it blew up one day and after the change my hang was gone and I could drive normally without zeroing those tables)
1 - Wrong, doing this will not "hide" any problems. And if you let off throttle at redline, the rev hang can last for many seconds, not just 1 second
2 - Incorrect. Zeroing the tables will NOT make the car buck on lift off
3 - Wrong. This is the cause of rev hang and this is the correct fix.

Originally Posted by rawkus View Post
I'd be careful with zeroing out everything in the low rpm range. This can lead to the car dying while coming off throttle after cruising.

Dan
Umm those stock are already zero'd out in the low range.

Last edited by Boosted Tuning; May 2, 2013 at 12:02 PM.
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Old May 2, 2013, 03:34 PM
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Originally Posted by Boosted Tuning View Post
All that doesnt matter. Yes the decel fuel tables were defined "wrong" but that doesnt matter. All that matters is that doing this works.



1 - Wrong, doing this will not "hide" any problems. And if you let off throttle at redline, the rev hang can last for many seconds, not just 1 second
2 - Incorrect. Zeroing the tables will NOT make the car buck on lift off
3 - Wrong. This is the cause of rev hang and this is the correct fix.



Umm those stock are already zero'd out in the low range.
Depends on the rom... I have found that Tephra V7 cars (as they are all zero'd) with stalling from high rpm issues can be fixed with adding some percentage there.

Dan
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Old May 2, 2013, 04:57 PM
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Originally Posted by rawkus View Post
Depends on the rom... I have found that Tephra V7 cars (as they are all zero'd) with stalling from high rpm issues can be fixed with adding some percentage there.

Dan
No, it doesnt depend on the ROM. They all have the first couple boxes zero'd when stock. Also its not zero'd out on V7 ROMs either (the stock tables I posted are from an unmodifed V7 ROM).

Its true though, that adding some demand there can help get rid of stalling when dropping from high RPM.

Last edited by Boosted Tuning; May 2, 2013 at 05:01 PM.
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Old May 2, 2013, 10:02 PM
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I'm loving the cat fight... I wish i had enough knowledge to slap someone in the face with some tuning bs i pulled out of my *** to try and discredit a legitimate tuner to make me look better... I would sooooo be on this... But i dont. So i am waiting for my car to finish to impliment this and see how she likes it...
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Old May 3, 2013, 07:56 AM
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I have a ton of respect for Boosted and I am not trying to make myself look better. I am speaking from experiences I've had and trying to help the community as a whole. I don't tune for a living. I will investigate and report back. From my experience taking cars from a stock rom to V7 has caused issues with stalling coming down from high rpm. I have found differences in these tables and revised them and solved the stalling issues, that is all.

Dan
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Old Jun 19, 2013, 01:39 AM
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i do this on my 88580714 rom. hang still there.. i notice my afr stay at 13/13.5 during throttle release and brake engine moment..

Anyone?
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