Scanner Code definitions and relationships

[Bamba]

After pulling some "Live Data" yesterday, it sure would be good to have some information on the relationship between things like

SHRTFT %, LONGFT %, ... SHRTFTB1 % etc

I know that these are "Short\Long Term Fuel Trim designations but what I don't know is ...what the relationship is between these and the other values pulled by my scanner.

Thx in advance

 

[steamroller]

The STFT (short term fuel trims) are what the O2 sensor is reading as far as being rich or lean, this info is relayed to the PCM and it comes up with an average which is what your LTFT (long term fuel trims) are. The LTFT are stored in the PCM and this figure is applied everytime the engine is running. Ideally you want the STFT to be near zero, but usually they're never perfect

 

[Bamba]

Thx Steamroller.... I've found some decent sounding data for STFT and LTFT... Let me know what you think...

http://www.youtube.com/watch?v=Ay63dWxnr7U&feature=channel

 

[steamroller]

That explained it better than i did, and that voice sounds like my cell phone when it reads text messages lol