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Old 07-22-2010, 05:07 PM   #1
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Default Oscillating AFR

I tried to search for this probably but wasn't having any luck. My car is running fine, but when I'm just cruising at any speed my AFR's are constantly bouncing back and forth between 13.0 and 16.5 (the MS reads leaner than my wideband). I originally suspected the MAP signal, but I've moved it around a few times with the same results. Also any changes in MAP (which look minimal to me) do not seem to have a correlation to the AFR. Any idea what it could be?

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Old 07-22-2010, 05:10 PM   #2
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smooth out your fuel map?
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Old 07-22-2010, 05:11 PM   #3
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Your closed loop settings are too aggressive. Post your MSQ
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Old 07-22-2010, 05:34 PM   #4
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Quote:
Originally Posted by 18psi View Post
smooth out your fuel map?
At cruise it's just sitting in the same cells so there's nothing to smooth, as far as I understand.

Quote:
Originally Posted by Jeff_Ciesielski View Post
Your closed loop settings are too aggressive. Post your MSQ
Uploaded. I feel retarded just admitting this, but I have not been able to find anything relating to closed/open loop in TunerStudio aside from idle settings
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File Type: msq nb.msq (77.1 KB, 86 views)
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Old 07-22-2010, 05:46 PM   #5
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Your EGO is enabled but the step size is 3% so it's adding or subtracting 3% fuel every time it makes an adjustment. It's possible those swings are too big and causing it to oscillate about the target AFR. Drop the step size to 1%, and also increase "ignition events per step" to something more like 60-80, and see if that makes a difference.
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Old 07-22-2010, 06:31 PM   #6
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Quote:
Originally Posted by ScottFW View Post
Your EGO is enabled but the step size is 3% so it's adding or subtracting 3% fuel every time it makes an adjustment. It's possible those swings are too big and causing it to oscillate about the target AFR. Drop the step size to 1%, and also increase "ignition events per step" to something more like 60-80, and see if that makes a difference.
Yeah, I'd say that helped a bit.



Thank you!!!!
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Old 07-22-2010, 07:12 PM   #7
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Glad you got it sorted out. Any time idle/cruise are loopy, check EGO/Close Loop settings first. Then look to see if you have some crazy problem with your fuel table or AE
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