Long Term Fuel Trim (LTFT) always zero

Any form of normally aspirated power mods.
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chiron
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Long Term Fuel Trim (LTFT) always zero

Post by chiron » Mon Feb 24, 2020 5:43 pm

My LTFT is always zero. It never changes. I first noticed this when Carl at rrp did some MAF scaling and tuning for me with Mazdaedit.

I can see STFT moving a few % during closed loop but LTFT is always zero. It's been like this for over a year with no obvious issues.

Any ideas?
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Re: Long Term Fuel Trim (LTFT) always zero

Post by 13Black » Mon Feb 24, 2020 6:41 pm

Sounds like Carl did what he did correctly then.
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Re: Long Term Fuel Trim (LTFT) always zero

Post by New Duke » Mon Feb 24, 2020 6:41 pm

Doesn't zero just mean that your LTFT is bang on and the car is running well? So the ideal scenario?

Sounds like you have a good (RRP) tune and no fuel problems or vacuum leaks to me. But I'm sure others will chime in and set me straight if not.

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Re: Long Term Fuel Trim (LTFT) always zero

Post by chiron » Mon Feb 24, 2020 8:41 pm

It was zero before we started the mapping process and it is still zero now. The point is that it is ALWAYS zero. Reading around on the cesspit of arguments that is rx8club.com I found the following useful post that suggests there are 3 MAF points at which the LTFT is written.

https://www.rx8club.com/series-i-troubl ... ost4347055
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