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is thsi a good procedure, to Tune MAF transfer? 
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DIP8 - Involved

Joined: Tue Jan 14, 2014 6:05 pm
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hello forum. i have a real problem, finding a MAF with a given transfer function. my ecu is diy from the scratch,and my car , has no MAF (or injection for the time).
i was thinking of buying a bosch MAF model, that can be found here : http://www.auto-consulting.it/DWN/Mass_ ... sensor.pdf for the reason, i have a "starting" transfer function.

so i was thinking, in order to tune that function, i would go something like this :
have the AFR at constant 14.7 . the air which comes in, is given by the MAF transfer function. so if i monitor the Narrowband oxygen sensor, and i dont see stoichometric, it means, that the maf transfer function needs adjustments (and a bunch of other thinks ofc).

so i will be a t iddle (1000rpm), withc constant AFR, and adjust the values of the transfer function, untill the oxygen sensor's outpout cant be improved any more...

does this seem like a fine idea?


Sun Feb 16, 2014 7:03 pm
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Narrowband sensors are all but useless. Get a wideband from Alan: http://14point7.com or DIY one of those first. (though it's not worth it)

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Sun Feb 16, 2014 8:41 pm
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DIP8 - Involved

Joined: Tue Jan 14, 2014 6:05 pm
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well yea. i have seen again that they are useless. but appart from that, if i had a wideband, would the procedure work? :D


Mon Feb 17, 2014 12:59 pm
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Joined: Sun Jul 18, 2010 2:35 pm
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the commanded lambda needs to be 1, than you just adjust the maf transfer function until you get the reported lambda of 1.
With a narrowband sensor, adjust till you get it osilating around .47v
With a wideband controller make sure its reporting around lambda 1

This is also the same way I tune a VE based SD table.


Mon Feb 17, 2014 1:33 pm
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Joined: Tue Jan 14, 2014 6:05 pm
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cool! thanks allot!! :)


Tue Feb 18, 2014 10:59 am
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Im confused... wouldn't he need to go much richer than Stoich when "flow testing" the MAF at higher air flows (thereby higher engine load)??. He won't be able to calibrate the MAF-"scaling/characterization" just free revving in Neutral... will he?


Fri Apr 24, 2015 6:18 pm
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Marek0086 wrote:
Im confused... wouldn't he need to go much richer than Stoich when "flow testing" the MAF at higher air flows (thereby higher engine load)??. He won't be able to calibrate the MAF-"scaling/characterization" just free revving in Neutral... will he?


You can scale a lot of it before you get to the point where you would want to run it richer than stoichmetric. Once you scale a lot of the lower flow area, idle, cruise, mild acceleration, you can extrapolate the rest of the curve fairly easy.

Yes you should be able to scale the the maf by just free reving in neutral, but it won't go but so far. And have the fuel injectors setup properly is critical for proper maf operation.


Wed Mar 16, 2016 1:19 pm
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