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VE Correction

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I am running lean around 1800 rpms. lambda 1.29/lambda Target .90=1.433333. My ecu does not make the correction. How do I calculate it if the cell I am tuning reads 85?

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Looks like you are about 31% lean.

Are you sure its not interpolating between the 58 and the 85 cell?

That would put the cell at 111, seems a bit high?

Most ecus that i've seen are defaulted to 10% max correction on the EGO side of things. You need to get your cells closer before the

ecu will compensate, thats why its not doing it.

Hope that helped

You are not in 85 cell, as 13bjunkie said ECU interpolating between 58 and 85 cell. You can see output value in lower left corner and it's 78. If your measured AFR when you are exactly in 58 and 85 cells matches your target AFR but between you have a lean spot, then you should add an additional coulumn in your VE table.

Thank you for the help. I really need to steady state the fueling to be exact. So the VE current would tell you if you are in that cell? 13Bjunkie how did you do the math to figure out that it is 31% lean? Thanks 13Bjunkie and Graf. I attached another pic.

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jumping from 59 to 85 is a huge change for neighbouring cells, the chances are that this area of the map isn't linear and therefore need higher resolution, add another column for 1750 and re-tune that area.

I get 43% lean, if you use have/want formula, 1.29/0.9=1.43 or 43%

Yeah so in your current picture there, you are interpolating to the next cell a bit. Your cell shows 50, but your actual shows 52, so its adding a bit from the other cell.

Im a bit confused on the math that andre teaches sometimes, and its probably that i really suck at math, its just something that im not very good at . What i usually do is divide the smaller number by the bigger number and subtract 100 from it

i also used this haha. http://www.marshu.com/articles/calculate-percentage-increase-decrease-percent-calculator.php

Chris, cheers mate. Thanks for the info. I need to steady state the fueling and see if it is still out of whack and see if I need the other column. The tuner that looked over the log did not do a good job. Have/Want YES!! I couldnt find it in the fundamental course, be nice if they had all the formulas listed instead of looking through every module. Correct me if I am wrong. Using the numbers from the pic attached. 1.08/.93= 1.16 16% lean, "I know its mixing with the other cell" So the cell that reads 50, 50+16%=58 that will be my new number for that cell?

13bjunkie, Gotcha!!!! Thanks for the help.

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You need to be in the center of the cell in order to make accurate changes. Are you making steady state tuning on dyno or not? It's quite complicated task to do it without dyno.

At the moment I am not using a dyno. I just wanted to get my head around things before I do get on the dyno.

Just to add to the discussion, if you're seeing a reading of 1.29 lambda then there is a pretty good chance that this would have been the result of a lean misfire. It would be unusual to actually achieve reliable combustion with the lambda this lean - Normally you start seeing a lean misfire when you move leaner than perhaps 1.10.

Can you or someone elaborate on this? Lean misfire? could this happen because of the big cams i have? What do I need to do to fix this problem? I added some fuel.

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Bump for help

Increase resolution of VE table, as already written.

If your AFR is too lean you can get to a point where the engine can't reliably ignite the air fuel mixture and this results in a lean misfire which then causes the mixture to read even leaner. The solution regardless would be to add fuel but my point was that if the engine is suffering from a lean misfire then the actual lambda reading may not be as lean as the sensor indicates.

GRaf I added another column. Coming out of first, it feels a lot better. Before it would fall on its face and pick back up again. I guess that was the lean misfire. low rpms in second it starts to buck. I gotta take another log and see if I need more fuel. I attached a few pics, if you dont mind can you have a look? Should I also add another column for lambda and ign?

Andre thank you for the info.

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You need to tune the new column, you've just copied the lower value across which won't help matters.

There is a massive jump in your ignition between 1500 and 2000, I would add another column between the two, 1750, and it will need tuned.

Cheers Chris, I am going to log next time I drive the car and use the have/what formula to tune it as best as possible. Waiting on a mate to have time so I can put it on the rollers and steady state the fueling. Attached is a GIAC Vr6 chip ign table, Paul from KPtuned got the table as close as possible for 93 octane "US fuel". You think it would be feasible to use his ign map for the mean time, until I put it on the rollers?


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Happy Friday bump

If your ignition map was tuned previously then add a column in at 1750 and interpolate your values from each side until you can tune it properly. This will only visualise what the ECU is doing naturally.

The hesitation that you mentioned previously is likely from you holding your leaner for longer as you didn't tune the new column in the fuel map

Cheers Chris

After adding another ve and ign column around 1700, the motor is behaving a lot better. Thank to all that helped.

Glad we can help

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