MAFLESS VE Tuning
09-16-2004, 08:15 PM
#41
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I've messed with the VE table (primary only, don't have the secondary) with both the MAF plugged in and unplugged and it doesn't do anything to the LTFTs. I can tell when I make changes to it by the way the motor runs but it doesn't change the LTFTs. I believe jimmyblue said before that the VE table is used for rapid thottle changes where the MAF is inaccurate, kinda like an accelerator pump. Anybody hear have an 01 or 02 that has had luck tuning the LTFTs with the MAF? Jimmyblue are you? I'm starting to think that not having the secondary VE table is the key to why it doesn't work for me.
Last edited by screamn03; 09-16-2004 at 08:22 PM.
09-16-2004, 10:05 PM
#44
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It looks suspicously like you started out first by scaling your 400, 800, and 1200 rpm rows before you started tuning using your LTFTs. Are you seeing positive trims over there?
It helps to try and adjust the VE cells that are outside what you normally reach to a realistic number, like a lot of the ones at 15 kpa. It's hard to reach all of them, but there is nothing wrong with "fudging" a few to smooth things out. It is pretty safe to say that the VE cells at 15 kpa will not be higher than the cell directly beneath them.
Sometimes if I see a trim that I can't adjust using the secondary VE I will use the cells around it (usually above or beneath) to "nudge" that part of the table where I want it.
It helps to try and adjust the VE cells that are outside what you normally reach to a realistic number, like a lot of the ones at 15 kpa. It's hard to reach all of them, but there is nothing wrong with "fudging" a few to smooth things out. It is pretty safe to say that the VE cells at 15 kpa will not be higher than the cell directly beneath them.
Sometimes if I see a trim that I can't adjust using the secondary VE I will use the cells around it (usually above or beneath) to "nudge" that part of the table where I want it.
09-16-2004, 10:11 PM
#45
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I did do that (scaling) when the maf was plugged up. Then i started using the trims to tune them and now i am not seeing any postive trims. They are all 0--2
I will get around to fudgin the cells I just got them where i wanted them tonight so I havent had time to go any further
I will get around to fudgin the cells I just got them where i wanted them tonight so I havent had time to go any further
09-16-2004, 10:14 PM
#46
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Originally Posted by HumpinSS
I did do that (scaling) when the maf was plugged up. Then i started using the trims to tune them and now i am not seeing any postive trims. They are all 0--2
I will get around to fudgin the cells I just got them where i wanted them tonight so I havent had time to go any further
I will get around to fudgin the cells I just got them where i wanted them tonight so I havent had time to go any further
09-16-2004, 11:27 PM
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HumpinSS, at 800rpm 50kPa you have a value of 31. That does not seem to "fit" that general area.
You can help your idle quality a lot by smoothing those cells out. As the PCM goes over this individual cell, it will vary dramatically in fuel delivery between the surounding cells.
What I do is this:
Set the decimal precision to 1 and reload the table.
Then manual smooth out the table using the 3D graph. When tuning VE I tend to not use the smoothing feature as it changes too many of my VE values. Once you get a nicely smoothed VE table, smoothing it by hand is very easy.
A smooth VE table will help transitions between cells and thus provide smoother engine operating characteristics.
You can help your idle quality a lot by smoothing those cells out. As the PCM goes over this individual cell, it will vary dramatically in fuel delivery between the surounding cells.
What I do is this:
Set the decimal precision to 1 and reload the table.
Then manual smooth out the table using the 3D graph. When tuning VE I tend to not use the smoothing feature as it changes too many of my VE values. Once you get a nicely smoothed VE table, smoothing it by hand is very easy.
A smooth VE table will help transitions between cells and thus provide smoother engine operating characteristics.
I will work on smoothing this thing out tonight and repost another screenie 
09-17-2004, 08:26 PM
#54
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That looks a lot better!
Do you have one of our later versions that allows you to modify decimal precision with the table display? If so, select 1 from the drop down, then reload the table. Now you can hand smooth and save it with much better accuracy.
The smoother the table is, the smoother your throttle transitions will be and the smoother the engine will run overall.
Try to also do a lot of your tuning in very similar weather conditions. If you tune in various weather conditions, be sure to hit as many cells as you can so your adjustmenets are even.
if you tune your entire table on a hot day and then play with the low RPM areas on a cold day, your table will not be very accurate for one of the sections depending on the weather condition you are in.
Do you have one of our later versions that allows you to modify decimal precision with the table display? If so, select 1 from the drop down, then reload the table. Now you can hand smooth and save it with much better accuracy.
The smoother the table is, the smoother your throttle transitions will be and the smoother the engine will run overall.
Try to also do a lot of your tuning in very similar weather conditions. If you tune in various weather conditions, be sure to hit as many cells as you can so your adjustmenets are even.
if you tune your entire table on a hot day and then play with the low RPM areas on a cold day, your table will not be very accurate for one of the sections depending on the weather condition you are in.
09-17-2004, 09:14 PM
#55
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Originally Posted by Magnus
That looks a lot better!
Do you have one of our later versions that allows you to modify decimal precision with the table display? If so, select 1 from the drop down, then reload the table. Now you can hand smooth and save it with much better accuracy.
The smoother the table is, the smoother your throttle transitions will be and the smoother the engine will run overall.
Try to also do a lot of your tuning in very similar weather conditions. If you tune in various weather conditions, be sure to hit as many cells as you can so your adjustmenets are even.
if you tune your entire table on a hot day and then play with the low RPM areas on a cold day, your table will not be very accurate for one of the sections depending on the weather condition you are in.
Do you have one of our later versions that allows you to modify decimal precision with the table display? If so, select 1 from the drop down, then reload the table. Now you can hand smooth and save it with much better accuracy.
The smoother the table is, the smoother your throttle transitions will be and the smoother the engine will run overall.
Try to also do a lot of your tuning in very similar weather conditions. If you tune in various weather conditions, be sure to hit as many cells as you can so your adjustmenets are even.
if you tune your entire table on a hot day and then play with the low RPM areas on a cold day, your table will not be very accurate for one of the sections depending on the weather condition you are in.
This morning when I smoothed the table i took it out 1 decimal place but forgot to copy and paste the number to the secondary table when i reopened the tune and that is why it looks like that.
Does the editor save the preferences you choose when you fool around with the decimal places?
joel
09-18-2004, 06:12 AM
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I have a 00 A4, after reading this post I am confused. To correct my ltrims I am suppost to edit the second ve table and leave the first alone? I do have both tables but the first is in increments of 5 and the secondary table is not as big with increments of 10.
09-18-2004, 02:30 PM
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I've messed with the VE table (primary only, don't have the secondary) with both the MAF plugged in and unplugged and it doesn't do anything to the LTFTs. I can tell when I make changes to it by the way the motor runs but it doesn't change the LTFTs.
My question(s) is this. Can I get my LTFTs squared away without the MAF and then just plug that MAF back in, would that be the best approach? Also, if the MAF is the primary device being used for the airflow calculation from 4000+, then when it's disconnected will the VE table affect PE? Do you look at the PE multiplier and then see if it matchs you a/f ratio, if not then add or subtract to the VE table accordingly?