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Long Term Fuel Trim at -21,1%


Topic starter

I have a Nissan March(Micra in Europe) 2014 1.6L (4 cylinder naturally aspirated FlexFuel engine), i bought a Creater 3001 Scan Tool and upon checking the data i noticed that LONGFT1 is -21.1% SHRTFT is ok, it does not go above +-10% and after warm up at steady speeds is 0.0%. Car runs fine should i worried about it?

4 Answers

Air related....Mass Air Flow....spray clean it  

o2 on scanner

Warn engine, do compression test

Exhaust restriction, Cat converter P420


Fuel Related:

leaking injectors

bad fuel pressure reg

Fault in Evap 

high fuel pressure




LTFT indicates the car is running rich, check for leaking injectors or possible bad fuel pressure regulator. You say the car is running fine, I would drive the car and watch the data. Compare the data when the car is cold vs hot.....

Already did that, the data that i'm talking about is when engine is hot for some weird reason is stuck at -21.1% some times while driving goes to -20%, what can happen if i don't fix that?



If it’s running that rich and you do nothing, you’ll ruin the converter.