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MAF flow rate vs MAF frequency

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Old Mar 29, 2002 | 10:40 AM
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Default MAF flow rate vs MAF frequency

So has anybody created a table or excel document to help convert the MAF flow rate vs MAF frequency so we can tune more accurately? I am trying to tune my LTRIMS more evenly but don't know what MAF frequency's to change at which points.
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Old Mar 29, 2002 | 11:29 AM
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Default Re: MAF flow rate vs MAF frequency

Autotap allows you to log raw MAF input frequency (under fuel, scroll a ways down) - that would probably be easier and more precise.

Chris
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Old Mar 29, 2002 | 11:31 AM
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Default Re: MAF flow rate vs MAF frequency

Yea, somebody else just told me that too. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" /> I swear I looked all over for that and didn't see it. I thought I only saw a gal/sec or something like that. I will look for it in autotap again.
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Old Mar 29, 2002 | 02:05 PM
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Default Re: MAF flow rate vs MAF frequency

OK, I found it. Now I guess i have another question...

If I avg out my LTRIMS, would I multiply through the whole table by that number? For example, my avg LTRIMS are +10. I would multiply through the whole MAF table by 110%. Is this correct? This is essentially what the base setting on a MAF translator does right? I know I will go in afterwards and fix any valleys and peaks though in the table to make it more accurate after the avg correction factor is put in. I am aiming for around -4 all over so the computer won't screw me up by adding fuel when I am trying to tune for WOT.

<small>[ March 29, 2002, 02:05 PM: Message edited by: Nic00Z28M6 ]</small>
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Old Mar 29, 2002 | 03:11 PM
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Default Re: MAF flow rate vs MAF frequency

Yes, you would multiply the entire MAF table thru by 110%. The base setting on the MAFT shifts the frequency, either up or down, depending on what you dial in.

After you have uploaded your new PCM program, you should drive the car around for 15 or so minutes in order for the PCM to learn your new MAF table values. Then see if the Lterm fuel trims are being reduced.

You could do a PCM reset after uploading the new program, but you will always have to drive the car fir awhile for the re-learn process.

NOTE: When you multiply thru by 110%, you may run into the max value limit in the MAF table. I think it is 512, but I'm not sure. If you run into this problem, then multiply thru by 110% from 1500Hz to 10500Hz and then for the upper frequencies, mulitiple through by 109% for one block, then 108% and so forth.
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