part throttle mixture

[dian]

i have noticed the mixture at 50% throttle @2800 rpm and 115 mpa is 2% richer than at 100% throttle @ 2800 rpm and 115 mpa. this is more or less steady state accelerating in 3. gear (a4) on a 99 c5. as its exactely on the tuning points there are no interpolation issues. i cant think of anythig that might be causing this. (yes, pe is on in both cases.) any thoughts?

[joecar]

What is ignition timing at both those data points...?

Post log file.

[dian]

timing and iat are the same.

if you please would compare e.g. 2900/3000 rpm at frame 195 and 470 with frames 595/700. ad1 0.85 = 0.755 lambda, ad1 0.94 = 0.782 lambda (ad1 1.00 = 0.800 lambda). thats all 3.gear. second is generally a little leaner than third, i still have to find out why, but thats actually o.k.

[joecar]

Which wideband are you using...?

[joecar]

timing and iat are the same.

if you please would compare e.g. 2900/3000 rpm at frame 195 and 470 with frames 595/700. ad1 0.85 = 0.755 lambda, ad1 0.94 = 0.782 lambda (ad1 1.00 = 0.800 lambda). thats all 3.gear. second is generally a little leaner than third, i still have to find out why, but thats actually o.k.
From your log:
frame 195: MAP = 116 kPa
frame 595/700: MAP = 122 kPa

those are operating from 2 separate cells in the boost VE table (they are adjacent to each other, but their values are different. slightly).

[joecar]

BTW: You have a single huge spike in your B0101 VE table.

[dian]

i see the spike. thanks.

well, i originally made an average from a number of points from several logs and came up with 2-3% richer at part throttle. it would be a lot of work to find the points again and study all the logs.

however if you look at 590 and 693 we are at 118 map as opposed to 115/116 at 470/195. the curves are shifted as a whole. the difference in ambient pressure shows in the logs.

[ProperTuningOG]

Ever think of it in terms of transient. Transients are applied differently for WOT vs part. Part you will always have more applied as air gain is slower. I know you said the TPS is steady state but the fueling is not. Also, I have not looked at the log but if you are that high of KPA you would be forced, which would bring on an entirely different calibration for transient. IAT, timing, valve temp, injector size, fuel pressure/volume gain/loss....... Its all very different for forced induction.

Side note: This is normally where heads with a large intake runner on NA engines see lean spikes in the lower RPM high load cells on WOT/part hits from idle or lug it down pulls. The VE table will want a huge spike but that's not correct. The initial transient needs to be more. This is the reason we filter out TPS movement from while tuning steady state but the problem is the transient duration.

Or am I on some really good crack..... LOL

[dian]

not sure what your saying, team. i dont see any transient fueling input that would change with trottle position. do you? the tp is steady for several seconds in both cases. (cos3)

[dian]

Which wideband are you using...?

http://www.ecotrons.com/products/wideband-controller-alm-gauge/

[ProperTuningOG]

You need a CAX.

[dian]

im not that advanced unfortunately.

[LastCall]

I looked at the points in the log you referenced. There is a difference in map KPA and TPS between the 2 sets of frames. I would suspect that is where the variance is coming from.

2% is not a huge variance. Once you are the close, you need to blend the cells to close the gap, which can be tedious. 185 KPA and 5200 seems like a spike in the VE table as the one cell is pretty rich relative to the others.

A couple of notes, I would log MAP KPA, and not boost KPA. Log both sensor 1 and 2 (sensor 1) narrowband voltages and use that as a sanitary check against your WB along with IPW. Using maps as opposed to the charts will make the changes faster assuming you have good repetitive data, and then use the charts to fine tune.

Can you post a copy of your tune file?

[joecar]

+1 that was my next question, post tune file.

[dian]

thanks for looking. the tune is the same as in the other thread, i just changed the shift points. at 2800 115kpa is 93 and at 125 its 94. here it is.

as mentioned, the shift in the mixture is real. the fact actually doesnt bother me too much, i was rather trying to find out, if i was missing something, but apparently not.

last, not sure where your looking concerning 5200 rpm. i see 170 kpa and ad1 between .95 and 0.98 (lambda 0.785-0.794). frames 990/1260. i consider 11.6 afr ideal, at least at this rpm. i would go to 11.5 higher up. which brings me to another question. as you can see a jump of 2% lambda is not unusual from frame to frame. is that normal?

also, i used to logg both boost and map kpa and decided boost had less fluctuations, although not by much. im a bit irritated by the fluctuation here also, actually all the data is very volatile. the narrowbands are useless, they just show rich, one of them dying, at least i think, its slow. i just passed emission anyway, the cats apparently cant be destroyed.

[LastCall]

Some fluctuation is normal, I don't think 2% is a lot.

There is a lot of fluctuation in your map reading - I don't think it should be moving that much. How is it plumbed in? Could it be coming loose under boost? That would also cause fluctuation in your fueling since you are hitting a wider range of cells.