ecu fuel trim
11-18-2012, 01:27 AM
Post: #11
ecu fuel trim
It seems strange that the ECU does not have a target AFR table hidden
away somewhere ?? I was under the impression (from reading about the
Freedom ECU on club4AG) that it was capable of self tuning a number of
selectable maps according to driving style e.g. economy, normal and
sports modes. To me this implies having a target AFR table based on
TPS x RPM.

I gathered that once these maps were auto-tuned in closed loop, they
could be locked in, and later used in open loop. Maybe I read too much
into that article ? Or maybe you have a different version ?

My ECU (which is not super-sophisticated) can only store two maps. But
it will auto-tune to redline in closed loop, using the target AFR table. There
is an option to go to open loop above a specific TPS (maybe RPM) and use
whatever values you have setup in the map.

Seems to me you might need to dyno tune your WOT values using a
"safe" AFR. Then manually taper the map back intuitively to your last line
of auto-tuned cells. Fine tune by monitoring from your logs while running
open loop, and then lock it up Smile

Cheers... jondee86
Find all posts by this user
11-18-2012, 05:04 PM
Post: #12
ecu fuel trim
Hey Jondee yeah you are right about some versions of the Freedom
having target AFR values, unfortunately though mine does not have this feature Sad
I guess the sport mode is the "throttle map" mode that uses TPS x RPM
and the economy mode uses the MAP sensor.


"Seems to me you might need to dyno tune your WOT values using a
"safe" AFR. Then manually taper the map back intuitively to your last line
of auto-tuned cells. Fine tune by monitoring from your logs while running
open loop, and then lock it up"

I'm doing this at the moment, the ecu allows a percentage of fuel to be added or subtracted from the whole map so now I have richened the whole map by 5% allowed learning (14.7) for 60% of the map but I'm
still safe at WOT and full load by virtue of the 5% enrichment.

Sending the ecu back to the manufacturer for the full learning modification
is also an option.

An analogue brain in a digital World
Find all posts by this user
11-18-2012, 09:36 PM
Post: #13
ecu fuel trim
By coincidence, last night I read an interesting comment regarding the
Freedom ECU. It seems that when in self-learning mode, instead of the
ECU waiting for the load/rpm combination to place the cross hairs near
enough to the centre of a cell before making a correction, it takes a value
at random, and interpolates proportionately between the four nearest cells.

Adjusting cell by cell takes a lot longer, as the cross hairs have to linger
near the centre of the cell for a few milliseconds, and this does not happen
so often. Interpolating between the four nearest cells can always be done
with no waiting time.

I didn't explain that very well, but it ties back to your original post Smile

Cheers... jondee86
Find all posts by this user


Possibly Related Threads...
Thread Author Replies Views Last Post
  Removing front window trim zenki 7 11,107 09-07-2014 08:36 PM
Last Post: Ivan141
  Trim levels? Serencebey 17 21,508 11-20-2012 09:24 PM
Last Post: banpei
  AE86 Weather Stripping / Window Trim juantonwan 3 5,514 02-27-2010 07:11 PM
Last Post: aussiefan
  Trim Problem Serencebey 5 4,686 03-16-2009 08:07 PM
Last Post: Serencebey
  Removal of front seat belts - side trim ? Ian.G 13 10,345 02-10-2007 05:36 AM
Last Post: domi

Forum Jump:


User(s) browsing this thread: 1 Guest(s)

Contact Us | AEU86 | Return to Top | Return to Content | Lite (Archive) Mode | RSS Syndication