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Far out idea that fred is likely to shoot down immediately 
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LQFP144 - On Top Of The Game
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Joined: Mon Feb 11, 2008 10:52 pm
Posts: 549
Location: Arizona
just an idea
"The Block Learn Multiplier (BLM) is used as a long-term adjustment to keep the air/fuel ratio in check. The Integrator (Int) is used as a short term correction. Now, long-term is about 5 seconds and short-term about 20 times a second so they aren't any real length time. The BLM attempts to keep itself at 128, this is the midway point between 0-255. Any lower than 128 and it removes fuel, above 128, it adds fuel. The O2 sensor readings is what the ECM uses to change the Int. This allows the ECM to respond quickly to fuel needs. The ECM uses RPM and MAP/MAF to determine what BLM cell to use. If the Int. can't make a suitable correction, the ECM switches BLM cells. There are 16 BLM cells, each with a different fuel curve. On a properly tuned car, the BLM and Int will bounce around some but if you are idling at temp then they will begin to stabilize at 128. "

You snooze, you lose!

Wed May 25, 2011 8:38 pm
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QFP80 - Contributor

Joined: Mon Aug 29, 2011 12:59 pm
Posts: 46
IMO, self tuning, ie, finding and saving trim values for future use, is an important aspect of engine control. You shouldn't have to re-tune your engine because injectors are getting a little worn and the air flow sensor is drifting a little with age.


Tue Aug 30, 2011 5:56 pm
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