Ok back for more help.
Got the tune sorted out pretty well except for a low speed bucking issue
that's pretty violent, usually between 1500-2500 RPM light throttle.
Tried increasing timing in that area but no improvement, here's log and tune
any suggestions appreciated, thanks.
Try this out, it looks like the car goes really lean, the datalog you posted was pretty short and hard to get the info from but i did what i could with it.
Do you have an idle issue? looks like your idle is oscillating a bit and is kind of high.
Also need to know if this is a stick or auto??
Excellent results from the latest updated tune, thanks!
The low speed bucking is about 75% gone, only happens briefly under specific conditions but MUCH better overall.
From what I can tell the adjustments you made seemed to lean the tune out in the lower rpm "lugging" range,
which ironically is the opposite of what I was doing..lol still learning.
In an attempt to gain some more tuning knowledge I would like to fine tune that small problem area.
Given the changes you made what area/table do you suggest I look at ? I was thinking of starting by pulling a
little more fuel in the problem zone or increasing target AFR in that area.
To be honest it happens so briefly I still need to pinpoint where in the rpm range.
Thanks again, your knowledge and willingness to give your time are a great asset to this forum !
OK so to give really specific advice i need a datalog to work off of.
now lets talk about some of the things that I changed when i did the tune update.
1.) VE table: i simply smoothed the fuel table above the idle range this was a very minor change and likely affected the tune little
2.) AFR Table: I made large changes in this table but the changes were mainly in the idle and cruise ranges, these have little affect on the acceleration range of the vehicle. I removed the choppiness in this table, you want the AFR table transitions to be smooth and they need to make sense for the load range the engine will see.
3.) AE or acceleration enrichment : this is likely the major factor that fixed your stumble and buck, you may need to add some more to this curve. Like i said above without a datalog to look at it is hard to give you accurate advice.
I need to make a video on how to tune the AE this is a common issue and people have a hard time understanding how it really works and how much it affects the tune....
You can compare the two tunes to see exactly what i changed, hit 'file' then scroll down to 'compare tune' and load the tune you want to compare the current tune to. This will be most effective if you load the old tune then compare it to the tune i sent, you will then be able to really see the small changes i made and how heavily those small changes affected the tune.
Think I got a better datalog of the bucking issue, definitely better but still there under certain conditions.
This was second gear lugging in a parking lot.
It's not the end of the world I can drive around the issue but any help appreciated.
well it looks to me like the fuel table is still in need of some work, and the timing table needs love as well. The timing is most likely going to help the most, you need to adjust the timing up in the lower KPA and RPM areas. You can run as much as 35* at 1400 RPM in the low KPA range.
this lugging [surging] is due to the weak spark you have, and some slightly off settings attempting to turn on CL idle. The CL idle thing is harder to pin down without first addressing the other concerns.
If you like i can send you a picture or a copy of a more suitable timing table I use in My base tunes.
The last time I had it out (before winter hibernation) car ran awesome, bucking was 98% gone.
It happened once briefly but didn't get a log, I will fine tune more when it's out in the spring.
What really made the biggest difference was just working/smoothing the fuel cells.
Thanks again for all your help, I'm sure I'll need more assistance in the spring.