Short Term / Long Term

I am trying to understand how an ECU uses the sensor inputs. When you have two O2 sensors, it is necessary to tell the ECU which bank has which sensor. I can imagine how the algorithm could be modified so each bank gets the appropriate compensation.

Where I get confused is how is this interpreted to the long-term table which is only one entry per cell. If the short-term comp on one bank averages .5% increase and the compensation on the other bank is 4% decrease, how is that reconciled into the longterm table?

This is all ECU dependent.

Many times short term trims are bank-based to match the sensor, and when short term are transferred to long term, then it could average the two short term readings. In your example this would be (+1.75% trim). Eventually, I would expect the short term trim to be the same absolute amount but opposite polarity on each bank.

If you had a bank trim table, you could probably even that out.

Paul,

As David mentioned you'd have to ask the ECU manufacturer since you're working with a standalone ECU we aren't familiar with.

Can you view the long term trims in a table to get a feel for how they are stored and applied in terms of engine speed or load based zones?

Still waiting to discuss this with the manufacturer.

Looking at the long-term table, I see changes in fueling but can't determine any pattern based on what the short term has been doing.

Will report back

Sounds good!