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Zero or light load fueling issue

 
Old 01-31-2019, 01:18 PM
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Default Zero or light load fueling issue

Hi everyone. Getting the Miata back on the road after too many months down due to various excuses. Looking to try to educate myself on tuning the MSPNP.
The motor exhibits a strange momentary fuel cut every three seconds when under light or no load off idle. Itís like clockwork. Video wouldnít upload, but this screen shot shows which fuel cell Iím in (around 2000 rpm), and the green AFR line shows momentary lean events every 2-3 seconds. Any ideas where to start looking?
thank you in advance.
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Old 01-31-2019, 02:31 PM
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If you want answers instead of guesses post your tune and a log.
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Old 01-31-2019, 04:03 PM
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Default Current tune and data log showing event

Thanks again!
Attached Files
File Type: msq
CurrentTune.msq (90.4 KB, 8 views)
File Type: msl
2019-01-31_10.42.27.msl (41.6 KB, 9 views)
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Old 01-31-2019, 04:38 PM
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It's overrun fuel cut, or more generally, poor idle tuning. MAP reading dips under the 25kpa setpoint for overrun fuel cut, and then after a 1sec delay, it cuts fuel. Once MAP rises above 25kpa, the fuel turns back on, and the cycle repeats.
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Old 01-31-2019, 06:09 PM
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Originally Posted by Savington View Post
It's overrun fuel cut, or more generally, poor idle tuning. MAP reading dips under the 25kpa setpoint for overrun fuel cut, and then after a 1sec delay, it cuts fuel. Once MAP rises above 25kpa, the fuel turns back on, and the cycle repeats.
Thanks Sav! Iím going to invest some time in finally learning something about tuning this thing. It runs like **** pretty much everywhere. Cuts out under any real load. Throttle tip-in is miserable, which makes launching and shifting suck. All I can say is that it does run which is a step in the right direction from a couple days ago!
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