Christov Member 16 Member For: 15y 23d Posted 31/07/18 08:55 AM Posted 31/07/18 08:55 AM Howdy, Lately I've been getting into data logging and live monitoring of various things, using an OBDLink MX and CarScanner or DashCommand. One thing I've noticed is that my short term fuel trims are coming up very high (ahead of boost) under WOT, up to around +20%. I understand what fuel trims are and their purpose, haven't checked my long term fuel trims but will do so tomorrow. Is this normal for a tuned car? I can see it making sense that it's pumping in fuel ahead of the air it's about to take in. Any thoughts?
demon1300 Member 435 Member For: 14y 7m 21d Gender: Male Posted 31/07/18 01:00 PM Posted 31/07/18 01:00 PM STFT and LTFT are only used in closed loop (think light load & cruise secnarios) and not in WOT conditions where fuelling in open loop is calculated straight from the base fuelling map plus some additional modifiers.
Puffwagon Legacy Donating Member 16,348 Member For: 11y 8m 1d Gender: Not Telling Posted 31/07/18 01:03 PM Posted 31/07/18 01:03 PM I have a log that shows the stft going to max under wot. It always has. I dunno what the go is.
DarrylC Member 51 Member For: 13y 8m 18d Posted 08/08/18 01:20 PM Posted 08/08/18 01:20 PM On the Fords the STFT under Open Loop Fuel conditions will be based on the commanded lambda. So it you have a commanded lambda of 0.79 in Open Loop then your fuel trim will be 21%.
Puffwagon Legacy Donating Member 16,348 Member For: 11y 8m 1d Gender: Not Telling Posted 08/08/18 01:27 PM Posted 08/08/18 01:27 PM Interesting. So the trim values we see in the log could be from either source?
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