Idle tuning - question/advice
I opened up the BIS a ton.(incrementally)..so much that I can hear it hiss at idle. The car now holds an idle in SAS mode and .......ready.....no more AC on stall. WOO HOOO ! !
In doing so I noticed a few things....
idle load decreased slightly
ISCV steps decreased a ton (from mid 60s to mid 40s)
MAF Hz is much more stable
Idle likes to hang about 200 or so RPM higher than settings (It does settle to set values eventually)
Timing is more stable ( I believe I need to increase it a bit more from 8* to 11* or so to gain a bit more vacuum at idle)
AC on will cause the load to jump from 30ish to 50ish
Shifting seems to greatly improved (it is smoother...not so jerky)
In doing so I noticed a few things....
idle load decreased slightly
ISCV steps decreased a ton (from mid 60s to mid 40s)
MAF Hz is much more stable
Idle likes to hang about 200 or so RPM higher than settings (It does settle to set values eventually)
Timing is more stable ( I believe I need to increase it a bit more from 8* to 11* or so to gain a bit more vacuum at idle)
AC on will cause the load to jump from 30ish to 50ish
Shifting seems to greatly improved (it is smoother...not so jerky)
Thread Starter
Evolved Member
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Joined: Apr 2003
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From: Sellersville, PA
Sorry about the delay in responding but, yeah I did the same thing although I didn't open it a ton. I also adjusted the idle sensitivity a bit as well as the ISCV tables and it idles nearly like stock under all conditions.
I have my idle sensitivity set at 146......think it should be higher????
I ask becasue the car still hunts for idle RPM quite a bit.
It could be that I havn't given it enough time to adjust after opening the BIS.
The only ISCV table I played with was the A/C on.....I raised the last 2 values by 10 points each.
I ask becasue the car still hunts for idle RPM quite a bit.
It could be that I havn't given it enough time to adjust after opening the BIS.
The only ISCV table I played with was the A/C on.....I raised the last 2 values by 10 points each.
Thread Starter
Evolved Member
iTrader: (15)
Joined: Apr 2003
Posts: 955
Likes: 1
From: Sellersville, PA
I have my idle sensitivity set at 146......think it should be higher????
I ask becasue the car still hunts for idle RPM quite a bit.
It could be that I havn't given it enough time to adjust after opening the BIS.
The only ISCV table I played with was the A/C on.....I raised the last 2 values by 10 points each.
I ask becasue the car still hunts for idle RPM quite a bit.
It could be that I havn't given it enough time to adjust after opening the BIS.
The only ISCV table I played with was the A/C on.....I raised the last 2 values by 10 points each.
Yeah I played around the the AC on ISCV tables and adjusted them quite about, I think I was over 15 points each.
Originally Posted by Chabada15
sorry maybe im missing something but what is BIS?
The Idle stability control is this.....
<table name="Idle Stability Timing Control" category="Timing" address="174e" type="2D" level="2" scaling="uint16">
<table name="Settings" type="Static X Axis" elements="3">
<data>Sensitivity</data>
<data>Timing Limit</data>
<data>Untested</data>
</table>
</table>
Add this to your 94170015 xml. It will allow you to increase the sensitivity for idle. Helps to keep the car from hunting at idle. Stock value is 128....raise it to about 146.
Second question....I didn't mean raise the Hz values, I meant raise the scaling values. Sorry about that.
Third question.....Yes you should start to see some LTFT adjustments.
<table name="Idle Stability Timing Control" category="Timing" address="174e" type="2D" level="2" scaling="uint16">
<table name="Settings" type="Static X Axis" elements="3">
<data>Sensitivity</data>
<data>Timing Limit</data>
<data>Untested</data>
</table>
</table>
Add this to your 94170015 xml. It will allow you to increase the sensitivity for idle. Helps to keep the car from hunting at idle. Stock value is 128....raise it to about 146.
Second question....I didn't mean raise the Hz values, I meant raise the scaling values. Sorry about that.
Third question.....Yes you should start to see some LTFT adjustments.
Than means your controlling idle from the biss and not using the ecu to control idle. I read in a post that the proper way to adjust the SAS according to the manual is to activate SAS mode in evoscan and then adjust the biss to +/- 750 RPM. Then you will use the ecu to raise idle to your preferred setpoint after you deactivate the SAS. Right now you are just bypassing the stepper motor.
Yes that is exactly what i did. The problem is that my car will not idle at 750 with my big cams and ported head. It just won't happen.
So, basically, I opened up the BISS to past the ISCV allowable limit and run the car without the ISCV. It idles a little high...(I can tune it for lower RPM with fuel and timing) but it no longer stalls with the AC on and it transitions better than ever between shifts.
In a nut shell....I am using the throttle body as just a butterfly valve with an idle bleed screw. No need for the fancy electronics.
So, basically, I opened up the BISS to past the ISCV allowable limit and run the car without the ISCV. It idles a little high...(I can tune it for lower RPM with fuel and timing) but it no longer stalls with the AC on and it transitions better than ever between shifts.
In a nut shell....I am using the throttle body as just a butterfly valve with an idle bleed screw. No need for the fancy electronics.
The Idle stability control is this.....
<table name="Idle Stability Timing Control" category="Timing" address="174e" type="2D" level="2" scaling="uint16">
<table name="Settings" type="Static X Axis" elements="3">
<data>Sensitivity</data>
<data>Timing Limit</data>
<data>Untested</data>
</table>
</table>
Add this to your 94170015 xml. It will allow you to increase the sensitivity for idle. Helps to keep the car from hunting at idle. Stock value is 128....raise it to about 146.
<table name="Idle Stability Timing Control" category="Timing" address="174e" type="2D" level="2" scaling="uint16">
<table name="Settings" type="Static X Axis" elements="3">
<data>Sensitivity</data>
<data>Timing Limit</data>
<data>Untested</data>
</table>
</table>
Add this to your 94170015 xml. It will allow you to increase the sensitivity for idle. Helps to keep the car from hunting at idle. Stock value is 128....raise it to about 146.
So I went back and looked at the 94170008 rom and the ISCV tables. It appears that the values are substantially higher than that of the 94170015 rom. So...I adjusted my ISCV tables to nearly match the 0008 roms....and idle has greatly improved.
I did use the SAS mode again but still was unable to get the car to idle on it's own with SAS activated. So....I opened the BISS until I could hear it hiss. Then I turned it back in 1 full turn. VOILA...the car idles like a champ.
I assume that the 0008 allowed for greater ISCV movement because of the potential for us "dumb americans" accidentally putting in low grade fuel; the car would still hold an idle. In addition, we can look at the fuel and timing tables of the stock roms and see that mitsu was very conservative most likely for the purpose of warranties.
Thus, as we mod our cars we have to adjust it specifically to settings that will allow for optimum operation.
Only through studying the stock ROMs can we understand what the car was designed to operate like. Ah the joys of lessons from the past.
I did use the SAS mode again but still was unable to get the car to idle on it's own with SAS activated. So....I opened the BISS until I could hear it hiss. Then I turned it back in 1 full turn. VOILA...the car idles like a champ.
I assume that the 0008 allowed for greater ISCV movement because of the potential for us "dumb americans" accidentally putting in low grade fuel; the car would still hold an idle. In addition, we can look at the fuel and timing tables of the stock roms and see that mitsu was very conservative most likely for the purpose of warranties.
Thus, as we mod our cars we have to adjust it specifically to settings that will allow for optimum operation.
Only through studying the stock ROMs can we understand what the car was designed to operate like. Ah the joys of lessons from the past.
Idle finding.....Increasing timing causes an increase in idle vacuum. I am sure many of you knew this...but it is new to me.
With my Revolver cams at idle at 8* setting I hit about 9 on my vacuum meter. I increased timing to 11 and vacuum jumped to about 11. The increase in vacuum assisted in idle stability and lowered my MAF Hz to about 38ish.
Paul
With my Revolver cams at idle at 8* setting I hit about 9 on my vacuum meter. I increased timing to 11 and vacuum jumped to about 11. The increase in vacuum assisted in idle stability and lowered my MAF Hz to about 38ish.
Paul
