Bucking or stutter at low load/rpm
OK I've made a few changes as per tscomp's suggestions in the v7 cold start thread. Basically all I've done is:
- Put a block of 12's back in the idle areas of the ign map rather than the higher values I had.
- Set "Desired ISCV intial step position with AC off-Neutral" to these settings https://www.evolutionm.net/forums/9129618-post30.html
- Set "Desired IDLE Rpm - neutral" all to 1000
Cold start is good and moves down to 1000rpm fairly quickly. It used to rev a bit higher, but my cold starts were generally OK anyway.
I've only driven to work on these settings this morning, but I could not reproduce the stutter/hopping at 1900rpm. Need more time to ensure it's not there. Note that I think the A/C idle might still need some work as it did dip below 1000rpm a couple of times when I switched the A/C on and let the revs drop from high rpm. Still it didn't stall which is a good sign
- Put a block of 12's back in the idle areas of the ign map rather than the higher values I had.
- Set "Desired ISCV intial step position with AC off-Neutral" to these settings https://www.evolutionm.net/forums/9129618-post30.html
- Set "Desired IDLE Rpm - neutral" all to 1000
Cold start is good and moves down to 1000rpm fairly quickly. It used to rev a bit higher, but my cold starts were generally OK anyway.
I've only driven to work on these settings this morning, but I could not reproduce the stutter/hopping at 1900rpm. Need more time to ensure it's not there. Note that I think the A/C idle might still need some work as it did dip below 1000rpm a couple of times when I switched the A/C on and let the revs drop from high rpm. Still it didn't stall which is a good sign
Evolving Member
Joined: Apr 2011
Posts: 125
Likes: 0
From: West Seneca NY
Athanasios
Thread Starter
Evolving Member
Joined: Jul 2007
Posts: 172
Likes: 1
From: Australia
I've made a couple more tweaks to my settings and the stalling has improved. So far haven't been able to reproduce the stutter at 1900 ~30-40 load either, so that's good
My setup did not like these numbers in the ISCV with AC off table. It kept stalling on clutch in when rolling to a stop. The numbers at the lower temps did help drop the higher rpm at cold start, so I've left them there.
145
128
122
113
95
53
13
7
My new settings look like this:
145
128
122
113
95
75
35
25
I've also upped the idle timing areas to 14's. Im still not really sure how all of this can cure a part throttle stutter at 1900rpm though... But if it works, I'm happy
My setup did not like these numbers in the ISCV with AC off table. It kept stalling on clutch in when rolling to a stop. The numbers at the lower temps did help drop the higher rpm at cold start, so I've left them there.
145
128
122
113
95
53
13
7
My new settings look like this:
145
128
122
113
95
75
35
25
I've also upped the idle timing areas to 14's. Im still not really sure how all of this can cure a part throttle stutter at 1900rpm though... But if it works, I'm happy
the part throttle was more to do with the timing map i believe then anything else. keep it smooth as you possibly can. the clutch in stall is 100% iscv which you're fixing.
dont forget to tweak desired idle rpm also if need be.
dont forget to tweak desired idle rpm also if need be.
Evolving Member
Joined: Jul 2010
Posts: 133
Likes: 1
From: Overland Park, KS
I'm really confused as to why you keep going back to your timing map to fix your A/C idle dip. Most of that can be fixed through the ISCV tables and Desired Idle RPM tables as long as your BISS screw is properly adjusted, TPS reads normal and you don't have any vacuum leaks.
Thread Starter
Evolving Member
Joined: Jul 2007
Posts: 172
Likes: 1
From: Australia
I am using the ISCV tables to chase the idle dip. The timing map changes is just to get the idle a bit more 'solid' as I have 272 cams. I think it's fairly common practise to bump the idle timing up a bit on cars with cams.
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