assistance with VE table for Jeep

[skala308]

I am seeking advice on the GM section, since it is very difficult to get advice/comments on the Dodge section. It could be that there are more participants on the GM section, so I may get some help here. Thanks in advance, any assistance will be appreciated.

Attached is a printout of the LTFT + STFT of my Jeep 5.7 hemi. Should I increase the VE numbers on the cells in red, so doing making the mixture richer? The vehicles runs nice and smooth with the present settings in the tune file.

[Leva]

Are you running any filters? The red cells look reminiscent of transients on gear changes etc. Your fueling looks pretty good in the areas that matter on the graph.

[skala308]

Thanks Leva. Not sure what you mean by filters, but dont think so. These red cell (lean condition) is during deceleration with close to 0 throttle%. The timing on WOT has been set using a wideband sensor and running at 12.5 stoic. I have increased the PT timing and running just under the MBT values in closed loop.
I dont want to get into such a lean condition at deceleration to create detonation, unless I understand it all wrong.

Also, trying to run max closed loop at stoic of 14.7 and timing at MBT to get max power and fuel efficiency using PT and not WOT. This thing is like a rocket at WOT, up to 5800rpm.

[blindsquirrel]

Your Dodge PIDs are different than what GM uses so my standard filters don't work on your logfile, but if you set up something really basic like
[your EQ Ratio PID]=1&[your Throttle Position PID]>13
and Cell Hits Required: 25
and it will remove anything that's not commanding stoich, and anything that's not with the throttle open (I used '13' as it looks like your idle is at 12.5%, adjust if needed to whatever removes data when the throttle is closed). Some folks get really fancy with filtering by EVAP status and other stuff but just those 2 PIDs will get rid of most of the non-relevant junk you don't want.

[blindsquirrel]

You will never get detonation at closed-throttle coastdown. At such high vacuum there's not enough air to support the kind of cylinder pressures that could cause problems.

[skala308]

Thanks blindsquirrel. Being still new to this game, must first digest and figure out your advice. I have learnt much and the tuner who did the first basic tune before I got my own HPT and did further tuning, taught me a lot and is willing to assist when I ask for help. So, I will follow up on what seems a very good suggestion from you and also give feedback here, even if it is the GM section and not Chrysler/Dodge.

[blindsquirrel]

Another tip for when you're still figuring out which filters to use: Make a copy (or multiple copies if you want to try multiple filter versions) of your current non-filtered graph/chart thing, apply your filter string(s) only to the copy(copies), leaving your original graph unfiltered. That way you can open a logfile and switch between the charts and see what effect the filters have with a single click.

[skala308]

Thanks, much appreciated

[skala308]

Made some changes to good effect. Comments welcome

[Lakegoat]

Nice! I didn't look at the first scan, but this one looks about as close as you can get. If you scan tomorrow, it will be a little different, so don't go chasing your tail trying to get to 0.

[skala308]

Nice! I didn't look at the first scan, but this one looks about as close as you can get. If you scan tomorrow, it will be a little different, so don't go chasing your tail trying to get to 0.

Thanks, yes because other factors change, the results can vary slightly.
However, I just did a run staying in closed loop with a file where the VE table was bumped up with 25%, to see effect on STFT log. As I suspected, no real change, which confirms to me that making changes to the VE table for the Chrysler/Jeep will not influence rich/lean while in closed loop. The initial stoich numbers and O2 sensors will control the fuelling condition, plus the voltage at which going into WOT and thus open loop.

Been chasing my tail with this damn VE table.

[Lakegoat]

Maybe its because you have your MAP disabled? I don't know anything about Dodge tuning--

[skala308]

Maybe its because you have your MAP disabled? I don't know anything about Dodge tuning--

MAP disabled is factory standard for these 5.7 hemis. They use aircharge for Spark and Pressure Ratio for fuel trims, which is a math calculation of the MAP and Barometric pressure, coming from the MAP sensor.