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How do I change the commanded AFR

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Old 03-23-2008, 07:46 PM
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Default How do I change the commanded AFR

I have EFI Live and was just playin around and I see that the stock tunes are set to have an 11.7 AFR at max throttle. I seen a table that says .885 for max enrichment so does that somehow = the 11.7 afr?
Old 03-23-2008, 07:52 PM
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Not that I'm aware of, if thats in lambda .885=13.0:1 afr with a stoich of 14.70:1

If its eq ratio its insanely lean.
Old 03-23-2008, 10:10 PM
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convert your tables to read in AFR might be easier, its in properties. the only Max enrichment table that I can find in a search of a tun file is for hot fuelling mode which is irrelevant in normal driving. B3606 is the one im refering to.
Old 03-23-2008, 10:21 PM
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Originally Posted by macca_779
convert your tables to read in AFR might be easier, its in properties. the only Max enrichment table that I can find in a search of a tun file is for hot fuelling mode which is irrelevant in normal driving. B3606 is the one im refering to.
Thanks man, it;s easier to understand that way. The B3606 table is for wide open throttle isn't it?
Old 03-23-2008, 11:59 PM
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I think you probably want B3618. That is the PE (power enrichment) table. B3616 lets you set the throttle position to enable PE. Once it goes past that throttle point then the pcm switches to the PE table for commanded afr.
Old 03-24-2008, 07:29 AM
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Although EFI Live can display fueling in AFR, be aware that the pcm does not calculate final fueling in AFR.
Old 03-24-2008, 11:37 AM
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The 97-98 PCM's use lambda and 14.63:1 as a calculation; not EQ ratio like the later PCM's. I created an Excel spreadsheet with a graph (for both EQ Ratio and Lambda) so I can input the numbers to visualize the changes and simply copy and paste them into EFILive when finished. Columns include; Lambda, RPM, Stoich and Commanded AFR. It has helped me alot when adjusting this parameter.
Old 03-24-2008, 09:20 PM
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Don't do it w\o a wideband you might be suprised at the afr now.

what he said:
Although EFI Live can display fueling in AFR, be aware that the pcm does not calculate final fueling in AFR.

i am not familar with efi live but.
do not play with PE without a wide band
Old 03-24-2008, 09:59 PM
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Originally Posted by Doc
Although EFI Live can display fueling in AFR, be aware that the pcm does not calculate final fueling in AFR.
There is probably some canned PID or config to log commanded AFR though (even if it's math to convert from EQ behind the scenes) I imagine, right?
Old 03-25-2008, 12:08 AM
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Originally Posted by Frost
There is probably some canned PID or config to log commanded AFR though (even if it's math to convert from EQ behind the scenes) I imagine, right?
Yes you can log commanded afr. It has its own calculated pid.
Old 03-25-2008, 03:58 AM
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With EFI LIVE you can pretty much talk AFR all day long in most areas of the tune tool and all areas of the scan tool. The values in the tune that are AFR modifiers will all be an EQ modifer as the maths doesn't work out if its represented in AFR. This is all in the EFI LIVE Manual page 100 if your interested to know why.
Old 04-08-2008, 11:12 AM
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Manuals.. hmmm, I must read them one day
Old 04-08-2008, 06:22 PM
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I should read the manual also.

From my short time spent tuning so far, you can change it in B3618 as stated above. Then your goal is to make actual match commanded using a wideband. Getting there would make a good thread topic. I've been working on it in SD mode and simply scaling the appropriate area of the VE table by small amounts and keeping one eye glued to the wideband.



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