tune for lean cruse?
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From: Phoenix, AZ USA
tune for lean cruse? How would a person go about making their car run a little leaner when at cruse (say 16.5 A/F vs. the stock 14.7) to get extra fuel economy? Would you have to stay in open loop or can it be done in close loop? 
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From: Birmingham, AL
Could you change the stoich a/f in the PCM? I noticed it's there.... Don't know if it only applies to those lean cruise vehicles overseas or what. Not sure if it'd even make a difference if you changed it. Just a thought.
Just a thought. 
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From: Las Cruces, NM
Originally Posted by WS6 GreeN
Could you change the stoich a/f in the PCM? I noticed it's there.... Don't know if it only applies to those lean cruise vehicles overseas or what. Not sure if it'd even make a difference if you changed it. Just a thought.
Just a thought.Per Ken Kelly the stoich ratio is for alternative fuels only - propane, methanol, etc. According to him the pcm will just learn if you still have gasoline and change the stoich ratio.
As stated to get anything other than 14.7:1 during cruising you would have to be open loop. You would just change the open loop afr table. Of course you probably won't get any better gas mileage and will have troubles with tip-in issues (knock, etc).
Gary
