How to Eliminate "Rev-Hang" on the 05+ EVO 8/9s - Page 2 - EvolutionM - Mitsubishi Lancer and Lancer Evolution Community



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

Reply
 
 
 
Thread Tools Search this Thread
Old Jun 19, 2013, 10:58 AM   #16
Former Sponsor
Thread Starter
iTrader: (12)
 
Join Date: Jun 2005
Location: Chico, CA (Nor-Cal)
Posts: 2,382
Thanks: 0
Thanked 3 Times in 3 Posts

Drives: WW 04 RS, 330i, AW 04 STI (sold), 2 EVOs (sold)

Quote:
Originally Posted by el.guerrero View Post
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?
Email me your ROM and Ill check it out. Email in sig.
Offline
 
Reply With Quote
Old Jun 19, 2013, 11:19 PM   #17
Evolving Member
 
Join Date: Jan 2010
Location: Italy
Posts: 233
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: Evo IX GSR

thanks a lot sir.

Sent!
Offline
 
Reply With Quote
Old Jun 20, 2013, 04:16 AM   #18
Newbie
 
Join Date: Jan 2012
Location: Belgium
Posts: 6
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: Mitsubishi Evo IX

Boosted , I would appreciate if you could share how you fixed that, I will be looking at that rev hang soon...

Thanks
Offline
 
Reply With Quote
Old Jun 20, 2013, 09:46 AM   #19
Evolved Member
iTrader: (3)
 
fireroasted's Avatar
 
Join Date: Apr 2008
Location: CA
Posts: 860
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: USDM Evo 9 MR

This may be a too obvious comment, but just want to make sure folks remember before they get too complex into tables.....Always check for boost leaks periodically. I forgot who got all on me a few years ago about it, maybe it was Boosted, not sure, but boost leaks exist more than you think. I did have a few, and over time you will get them again. Its sometimes amazing how many little ones you get.

The point is when you do have little ones, you will have momentary lean conditions when you off throttle rapidly, because the vacuum will suck in lots of air not calculated by the maf. Unless you are really solid on your logs to see it happening via AFR you may just feel it as rev hang. The lean condition will give you that acceleration because that brief moment you have more vacuum than normal. This makes little boost leaks have this behavior. I had this scenario, and when I resolved some of those newer leaks I had (pinhole in IC pipe), I resolved the really nasty ref hang.

Another clue is if the rev hang seems to get slightly worse slowly over time.

Checking for books leaks should be a regular maintenance tasks. With a 30 dollar tester its super easy too. Its worth checking or confirming so you aren't chasing a fundamental mechanical issue with modifications to the tables.
Offline
 
Reply With Quote
Old Jun 20, 2013, 10:48 AM   #20
EvoM Moderator
iTrader: (26)
 
kyoo's Avatar
 
Join Date: May 2006
Location: US
Posts: 6,511
Thanked 34 Times in 34 Posts

Drives: IX

is there a reason the hang exists in the first place? i.e., designed that way on purpose?
Offline
 
Reply With Quote
Old Jun 20, 2013, 10:54 AM   #21
Evolved Member
iTrader: (3)
 
fireroasted's Avatar
 
Join Date: Apr 2008
Location: CA
Posts: 860
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: USDM Evo 9 MR

Quote:
Originally Posted by kyoo View Post
is there a reason the hang exists in the first place? i.e., designed that way on purpose?
To a certain degree the information I have read does indicate its intentionally, but only slightly. Once you start changing airflow, modifications, then you also change its behavior. When you have it real bad, you will know, as its clearly not safe for the engine. I had it bad enough at one point that the car could stay at 7k in neutral on track. I still have it a little under certain conditions, but it was due to boost leaks sucking in air under vacuum. Leaks were small enough that regular vacuum didn't cause much of a logable issue.

Mentioned earlier in this thread and in several others is the benefit to keeping revs slightly up during shifts, but stock its subtle.
Offline
 
Reply With Quote
Old Jun 20, 2013, 11:24 AM   #22
Former Sponsor
Thread Starter
iTrader: (12)
 
Join Date: Jun 2005
Location: Chico, CA (Nor-Cal)
Posts: 2,382
Thanks: 0
Thanked 3 Times in 3 Posts

Drives: WW 04 RS, 330i, AW 04 STI (sold), 2 EVOs (sold)

Quote:
Originally Posted by kyoo View Post
is there a reason the hang exists in the first place? i.e., designed that way on purpose?
Its there for emissions purposes, from what I've read.
Offline
 
Reply With Quote
Old Jun 20, 2013, 12:10 PM   #23
EvoM Moderator
iTrader: (26)
 
kyoo's Avatar
 
Join Date: May 2006
Location: US
Posts: 6,511
Thanked 34 Times in 34 Posts

Drives: IX

Quote:
Originally Posted by fireroasted View Post
To a certain degree the information I have read does indicate its intentionally, but only slightly. Once you start changing airflow, modifications, then you also change its behavior. When you have it real bad, you will know, as its clearly not safe for the engine. I had it bad enough at one point that the car could stay at 7k in neutral on track. I still have it a little under certain conditions, but it was due to boost leaks sucking in air under vacuum. Leaks were small enough that regular vacuum didn't cause much of a logable issue.

Mentioned earlier in this thread and in several others is the benefit to keeping revs slightly up during shifts, but stock its subtle.
Quote:
Originally Posted by Boosted Tuning View Post
Its there for emissions purposes, from what I've read.
interesting, good to know. maybe keeps the spool going up top? it's pretty damn annoying for regular driving
Offline
 
Reply With Quote
Old Jun 20, 2013, 12:15 PM   #24
Evolving Member
iTrader: (25)
 
evobros's Avatar
 
Join Date: Sep 2008
Location: CA, 90303
Posts: 455
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: 05 RR RS

Subscribe!!!
Offline
 
Reply With Quote
Old Jun 20, 2013, 03:06 PM   #25
Evolved Member
iTrader: (4)
 
Jersey Dino's Avatar
 
Join Date: Apr 2006
Location: North Jersey
Posts: 572
Thanks: 0
Thanked 1 Time in 1 Post

Drives: 2006 GG EVO IX, NA6(8)C Miata, 2014 Audi Q5 2.0, 2006 Triumph Speed Triple

In
Offline
 
Reply With Quote
Old Jul 17, 2013, 01:48 PM   #26
Evolved Member
iTrader: (11)
 
Blitz's Avatar
 
Join Date: Jan 2007
Location: Earth
Posts: 1,202
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: CT9A

Thanks for this. Rev hang is the very annoying. Really hoping this fixes it on my car. Two questions.

Question 1 - Updated the definitions (ROM 88590015). Opened ECUFlash and when I click on any of the new tables, I can only see the left column. Any idea how to see the right column so I can change the values? Sorry if noob question. Looks like this when I click on a table. Can't figure out how to expand the window.



Question 2 - For Step 1, are we supposed to change all 4 tables as you pictured, or just 2 tables? The wording is kinda confusing.

Quote:
Originally Posted by Boosted Tuning View Post
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 totally different:
So are we supposed to change Decel Fuel Cut Delay #1 & Decel Fuel Cut Delay #2, AND ISCV Demand TPS Adder, AC off (FFFF6E84) (mattjin fuel cut delay) & ISCV Demand TPS Adder, AC on (FFFF6E84) (mattjin fuel cut delay)? Or just change one of the pairs?
Offline
 
Reply With Quote
Old Jul 17, 2013, 02:02 PM   #27
Evolved Member
iTrader: (10)
 
Raptord's Avatar
 
Join Date: Mar 2009
Location: Gatineau, Quebec, Canada
Posts: 3,481
Thanks: 0
Thanked 8 Times in 8 Posts

Drives: AS Evo IX SE

Blitz, in regard to your question #1: Looks like there's a problem with the table definition. Double-check that there aren't any mistakes in the xml file.
Offline
 
Reply With Quote
Old Jul 17, 2013, 03:51 PM   #28
Evolved Member
 
Join Date: Jun 2008
Location: Sydney
Posts: 793
Thanks: 0
Thanked 14 Times in 13 Posts

Drives: AUDM_EVO IX

Add this to the Idle Control section of your xml.
The tables simulate the old throttle dash-pot device which slows throttle closing.
Its there to make decel smoother but Mitsu make it a bit to soft and you get rev hang.


<scaling name="ISCVSteps8" units="Steps" toexpr="x" frexpr="x" format="%.0f" min="0" max="255" inc="1" storagetype="uint8" endian="big"/>
<scaling name="ISCVSteps16" units="Steps" toexpr="x" frexpr="x" format="%.0f" min="0" max="255" inc="1" storagetype="uint16" endian="big"/>
<scaling name="Throttle%16" units="TPS %" toexpr="x*100/255" frexpr="x*255/100" format="%.1f" min="0" max="100" inc="0.392" storagetype="uint16" endian="big"/>


<table name="ISCV Dashpot Throttle Adder, AC OFF" category="Idle Control" address="3d6e" type="2D" scaling="ISCVSteps8">
<table name="THROTTLE" address="6f9a" type="Y Axis" elements="7" scaling="Throttle%16"/>
</table>

<table name="ISCV Dashpot Throttle Adder, AC ON" category="Idle Control" address="3d82" type="2D" scaling="ISCVSteps8">
<table name="THROTTLE" address="6f9a" type="Y Axis" elements="7" scaling="Throttle%16"/>
</table>
Offline
 
Reply With Quote
Old Jul 17, 2013, 04:11 PM   #29
Evolved Member
iTrader: (11)
 
Blitz's Avatar
 
Join Date: Jan 2007
Location: Earth
Posts: 1,202
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: CT9A

Quote:
Originally Posted by Raptord View Post
Blitz, in regard to your question #1: Looks like there's a problem with the table definition. Double-check that there aren't any mistakes in the xml file.
Thanks but I copied/pasted them exactly from the Boosted's post. Didn't miss any signs or anything. All of my other tables display just fine.
Offline
 
Reply With Quote
Old Jul 17, 2013, 06:18 PM   #30
Evolving Member
iTrader: (25)
 
evobros's Avatar
 
Join Date: Sep 2008
Location: CA, 90303
Posts: 455
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: 05 RR RS

I'm having this same problem but my car is stock with stock tune. Any ideas?
Offline
 
Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Stop your Car Stalling from Clutch in! simple_lancer EcuFlash 73 Aug 12, 2017 05:26 PM
psi based boost control tephra Evo X Engine Management / Tuning Forums 151 Jun 18, 2017 03:22 PM
Start-up Fuel and ISCV Tables Dynotech Tuning EcuFlash 80 Sep 20, 2016 01:30 PM
ISCV control system disassembly mrfred EcuFlash 399 Jul 29, 2016 07:02 PM
*Better* fix for P0300 tephra Evo X Engine Management / Tuning Forums 8 May 16, 2016 09:24 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -7. The time now is 03:54 AM.


 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: