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So I uploaded a test tune a couple weeks ago, and then... Life. SO I've been driving on this tune the entire time, mix of city and highway. At this point I'm assume the stored BLM's are pretty spot on for a tweak and re-test. Is there anyway to read them out of the ECM with an APU1 or should I just find some time and go for a long mixed drive?
See sig for ECM info if that matters.
thx
In most cases these values don't get stored. They are reset with each key on procedure. You'll need to drive and log these values. The good news is you can set up your logger and record each run until you have time to get back to it.
even if you could, and if they were stored, BLM history just isn't like that. the 'long term' part of the trims is only long term in the sense that it's an average from more than a few cycles.
since it's a running average, BLMs in a particular cell don't get better after weeks of driving; and they change constantly when operating conditions do.
you need to log BLMs over a long period of time and filter the data for good results.
If you know the addresses you could use a Mode 2 or Mode 3 command to get the data out.
It would take more mental power to apply the BLM values retrieved to your tune than a good datalog would.
Best to do a new all around drive (be sure PC doesn't go into standby!!!, BTDT) and make the changes that way.
I've done the mode 2/3 route a few times... works, but I'm going to echo the "go record a log" message.
depending on the PCM, some do learn "slowly" and require more than a couple drive cycles to end up with a fairly dialed in BLM grid immediately upon cranking. these PCMs use additional battery-backed RAM bytes to store "SAM" values that are used as a longer-term trim than BLM cells.
Life...
Finally got back to read up. I'll just run a long data log this weekend and adjust my tune. Trying out some new tranny shift points too.
Thanks