im using 8859 and havent experienced any of the jitter or what i would consider hesitation going into boost. it seems to be a little weak on large throttle transitions, but I think thats more to do with the transient fuel tuning than anything.

kpa to load and map volts to load are all 1:1/same on both sides, which is annoying since map to load is far from 1:1 in practice. I use the built in kavlico 5 bar scaling with the aem 5 bar map i have installed. i havent verified its right across all pressure ranges, but it shows 105kpa with engine off and the rest of the values all seem reasonable.
i also added a custom 2 byte map volt logging variable because i wanted to make sure i was logging the correct map variable that was actually used in the table lookup.

side note: changing the maf comp table at 1000hz and up seems to have affected my entire map? that single change seems to have really messed up my tune and ive been having all kinds of issues the past couple days. cruise went from perfect 15.0-15.4 afr to 13.8ish. i have closed loop completely disabled in periphery bits.

 

Well, 1:1 for map volts 2 kpa and kpa to load never worked out for me. Since i am tuning with 2150s . Omni 4 bar. anything under 100 kpa is 1:0.8 and above 100 kpa 1:1.1 ....

Currently suffering mechanical issue, full boost is very late. Perhaps a leaking waste gate diaphram or too much back pressure causing the waste gate to open.

 

why do you have your kpa to load like that? what did it accomplish that leaving it 1:1 couldnt?
I have never tuned a maf dsm/evo I have always gone straight to sd.

 

There are alot of ways to tune, i dont want to reduce/increase VE table values drastically instead i choose this method. For e.g with 2150s and 1:1 map volts2kpa my car idles solid at 11.3 AFR. Make it 1:0.8 afrs get better how they should be. In any case, VE table needs to be adjusted.

Alot of people might not agree with this but this worked for me.

 

anybody getting jitter when your not in boost or vacuum....cruising along around 2700-3k like i said not in boost but just barely on the throttle.

i know there was discussions about injector latency/scaling settings possible the culprit. or could it be maf scaling even though we're on sd i know those scalings still affect tune.
i read the mrfred posts on all that. anyone know if there is a definitive answer or even know the cause. if we know why its doing it maybe we can all put our knowledge together to get it tuned out.

mines5 is right theres alot of different ways to approach tuning. but i'd def look at mechanical stuff 1st before and after making an adjustment in maps just to keep things consistent!

 

Yes Sandman, i have tuned 3 different SD roms with different injector combo and all of them had that jitter. In 9653 you feel it the most.

Please read , Last page , post 227 and onwards.
https://www.evolutionm.net/forums/pr...-build-12.html

Same Sd jitter issue as we all are experiencing. This solution was also discussed and implemented in one of Mfred's thread.

 

Guys. At 1.3 bar I am logging load of 210. Which should be some where around 230. Do I need to increase last value in kpa to load table?

 

At this point, i think that is a matter of opinion. If you are aware of the discrepancy between load and kpa i think its simple to tune around it. or you can try to keep load and kpa equal.

 

​​​​​​i have also tried the fixes in mrfreds threads addressing it. Just seemed like it was never solved or at least debunked. I'm on a 9653 SD 2.0 ROM as I mentioned. Maybe after I smooth out my tune I'll copy maps and try a different version. Thanks for the reply!!!

 

Hi Guys..
anyone had used this rom and solve the jitter issues at RPM 2000 ?
need help here..tried all advised written but still on solve..monitored the AFR at RPM2000...the gauge shown sudden 9.0 afr at the RPM2000 andd made my car jitter...please helps...

 

You have mentioned 2 different problems.
Jitter - 9 AFR @ 2000 rpm.

1- Some people have resolved this issue using fuel pulsation damper. Some still experience it.

2- 9 AFR @ 2k rpm is a tuning issue.

 

hi mate,
can you help me to check and comment my tuning ? I might be not expert and willing to learn from the expert. Can we communicate through email ?..I shall email my rom to you.
Hope you can help me by your expertise.
awaiting your email address.
or you can reach me at nurulazlan.sahat@yahoo.com.my

 

Sure.

 

I just started using the 941 version, currently tweaking ve table in order to hit afr values in fuel table, so far everything is fine. I am not experiencing any jitters, if there is a jitter it is so minor that I haven't noticed anything yet. I have about 20-30 miles on this rom, a good amount of those miles are wot logging. Car is an 05 evo 8 that has basic bolt ons for now. I am experiencing some intermittent misfire/breakup ever since I turned up the boost but it has nothing to with this rom because it did the same thing on the oem maf rom that I was tuning earlier.

 

Well I figured out my break up issue, car runs really solid on this rom so far, i'm happy! Thanks to the people that developed these roms!