MLV always wants to lean out my VE table? WHY! - Miata Turbo Forum - Boost cars, acquire cats.

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Old 10-29-2009, 12:07 PM   #1
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Default MLV always wants to lean out my VE table? WHY!

MLV is consistantly always wanting to lean out my VE table by approx 6 points, so much so that I tuned by hand and have got a great drivable car in vacuum and boost so why does it insist on trying to tell me that I need to remove huge amounts of fuel from all cells in order to reach the AFR target?

See below link for screenshot...

http://s218.photobucket.com/albums/c...antsmelean.jpg

As you can see in the above log, my hand tuned VE table is giving a nice AFR of 14.555 @ ~2300rpm and MAP pressure of 40. You'd think that MLV when set to 'hard' would deviate at most probably a VE value of perhaps 1 in that particular cell and the 3 surrounding it? So why is MLV telling me I need to reduce the cells by a value of 6 to reach my AFR target?

The same goes with idle and other areas of the map. For instance my hand-tuned idle is great at ~14:1 and idle cells set to a VE value of 35, yet MLV insists I need to reduce the cells by 5 and makes the car undrivable.

What could be the issue?
FWIW, Im tuning with an LC-1 and Logworks at idle is near identical to TunerStudio.
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Old 10-29-2009, 12:15 PM   #2
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is your MLV setup to view the correct voltage output from the LC-1?

what does the gammae look like? upload the log and msq
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Old 10-29-2009, 12:17 PM   #3
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I rarely get an advance in fuel as well it is always leaning too, I'd like to see where this comes in!!!
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Old 10-29-2009, 01:32 PM   #4
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Log and MSQ are here drop.io Clayson

All WB interpretation is idential. i.e. 'LC-1 default' on LM programmer, TunerStudio and MLV.

Cheers,
Craig

Thinking about it, could it be that Baro being on is funking things up perhaps? It does swing all over the place in MLV.

Last edited by CRAIGO; 10-29-2009 at 01:33 PM. Reason: Baro
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Old 10-29-2009, 01:36 PM   #5
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that's exactly it. you wanna have it set the MAX correction to 100kPa and the MIN to something like 94-90kPa, depends what you see in your area. You're giving it WAY too much range and that screws it up hardcore.
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Old 10-29-2009, 01:58 PM   #6
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Could I just go into engine constants and turn off Baro correction? I drive at the same elevation anyway and it does sample the baro upon start-up so I guess leaving it off would be the simple, most accurate way?

Did you come to that answer after looking at my logs Brain? My map is the 250kpa IIRC and not the 400kpa version that has baro built in.

Cheers,
Craig
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Old 10-29-2009, 02:03 PM   #7
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i opened the MSQ saw Baro on. Which was one of my first thoughts, then looked at the settings for it.
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Old 10-29-2009, 02:13 PM   #8
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Thanks for the confirmation Brain!

The drive home in 10 minutes will be pleasing if all proves well and good.
I'll be sure to report back and expand on what differences are made.

Cheers,
Craig
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Old 10-29-2009, 03:16 PM   #9
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That sucks.............I had he same problem, and just hand tunned it. Wish I would of known how to correct it.
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Old 10-29-2009, 06:40 PM   #10
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damyn, how did I miss that! Sorry Craigo!
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Old 10-29-2009, 09:24 PM   #11
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It worked!

I 'guestimated' a min of 94 and max of 102 barometric correction and the car drove a hell of alot more smoothly, I thought I had it nice already but this was a real eye-opener!
After the 30 minute drive home I ran my log and MSQ through MLV set to 'hard' analysis and the deviations are a whole lot more accurate and believable now. Idle region doesn't really change at all so even without trying out the actual VE table changes that is created, Im now confident in using MLV for fine tuning cruise and boosted regions even further now. Thanks Brain for the confirmation!

Fixing this issue has brought forward other related questions if anyone can help?
I noticed that before changing the baro region, my maximum injector duty cycles were quite high for only 6psi of boost at 109%. Since reducing baro correction, my max injector duty cycle fell by nearly 20% to a more sane figure of 90% at 6psi of boost. Im running stock injectors btw. What's the reason behind this and can I now trust my 90% peak DCs?

I live in Manchester, England and my MS displays baro pressure at 101 when powered up without the engine running. From this base figure, what min and max values would anyone suggest?

Rich, don't worry about missing it mate, all is now well so Im very happy

Last edited by CRAIGO; 10-29-2009 at 09:53 PM.
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