08-10 SS Turbocharged General Discussion Discuss the 2008 - 2009 Chevy Cobalt SS Turbocharged. On sale since the second quarter of 2008.

maf tuning

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Old Jun 12, 2019 | 08:38 PM
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maf tuning

When i disconect the evap my stft go to -30 at idle is this normal ? Im trying to tune my fuel trims...
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Old Jun 13, 2019 | 02:20 PM
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Doesnt sound normal to me. No codes?
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Old Jun 13, 2019 | 02:45 PM
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Not normal at all.

Disconnecting the evap plug under the hood should disable the LTFT, unless you've moved your maf to the lower charge pipe without tweaking the maf tables significantly.

Also do a boost leak test with the plastic line going to the evap solenoid unplugged (one that runs back to the gas tank) and see if the solenoid has failed. I've had mine fail that way before.
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Old Jun 15, 2019 | 06:51 PM
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kk im gonna try again and see what happens . I think i forgot to reset my fuel trims last time before i started ...
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Old Jun 15, 2019 | 07:00 PM
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When you disconnect the evap solenoid it zeros the ltft and then you only have stft
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Old Jun 15, 2019 | 07:15 PM
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kk everything is good i tested it by just tuning my idle and the stfts went from -20 to - 3.1 with a few paste by % . Its raining to much to get a driving log atm . Ill have this thing dialed in tomorrow .

thanks guys
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Old Jun 16, 2019 | 01:41 PM
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Well things are going good for my fuel trims but im getting 14-16 degrees advance at wot and my spark tables are set to 12 degrees , why is the timing higher then what i have set in the tables ?
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Old Jun 16, 2019 | 02:49 PM
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Thumbs up

think i figured it out i set the base correction tables to 0 in the areas it was adding timing
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