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what's going on here (screenshot)

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Old Feb 25, 2005 | 02:39 PM
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Default what's going on here (screenshot)

This is a log from D3IMOS' car that he wanted me to look at. Besides his fuel trims being very negative, I noticed something weird. Sometimes his o2's will start reading really rich and his stft's and ltft's will stop updating as if he'd gone into PE. But it's not PE because this happens in fuel trim cells 3 and 7, mostly just cruising. Coolant temp is 172 F. Any ideas?
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Old Feb 28, 2005 | 02:00 PM
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TTT, no one knows?
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Old Feb 28, 2005 | 03:16 PM
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That's really weird. It looks like it dropped out of closed loop. When it did that the VE (or MAF table depending on the tune) put him rich. You can see the trims dragging the fueling down until that happens. I have seen weird things happen when EVAP cuts on. Log and see if that is happening.
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Old Feb 28, 2005 | 03:21 PM
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Need to add the fuel air multiplier to the PID list and use
it to track down the bad actor. Could be cat overtemp or
some other thing like that. When you see the FAM value,
you can check through the short list of enrichment adders
and see who matches. For debug purposes you can set
things to "tag values" like the COT table to 1.111, the
PR to 1.222, and so on just to make it obvious (just
remember to put them back when you're done).
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Old Feb 28, 2005 | 03:31 PM
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Originally Posted by jimmyblue
Need to add the fuel air multiplier to the PID list and use
it to track down the bad actor. Could be cat overtemp or
some other thing like that. When you see the FAM value,
you can check through the short list of enrichment adders
and see who matches. For debug purposes you can set
things to "tag values" like the COT table to 1.111, the
PR to 1.222, and so on just to make it obvious (just
remember to put them back when you're done).
Yeah, I was about to add it could be COT...or maybe a bad sensor?
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