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Discussion Starter #1
Hello,

I'm starting this thread hoping to learn more about reading data logs. I have found it very difficult to diagnose issues, yet alone recognize if there are any issues to start with. There seems to be a huge gap between tuner and customer knowledge. With tunes, we have access to all the same data as the tuners, however it seems almost impossible to interpret. It would be very beneficial to learn from other's data, issues and solutions. It's really difficult to learn how to use all the data available 🤷‍♂️

Muz :geek:
 

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Discussion Starter #2
The main issue I'm having at the moment is short term fuel trim (autocal). It spikes to +99% often since I got the car 35k kms ago. Long term is from -48% to 0%. I know I'm running rich as there is carbon build up on the plugs. I briefly got a P0172 yesterday but went away shortly after. I have fixed all PCV issues but still a few minor vacuum leaks. It takes 30 sec to drop from 20-10psi after PCV fixes (complies with standard boost leak test). Still have to check further but it doesn't seem anything major atm. Boost leak would make it lean though, yeah? Not really sure where to start looking for problems 🤷‍♂️

EDIT: I guess as it's losing air, it would run rich, but why the huge positive SHRTFT1?

Muz...
 

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Discussion Starter #4
What tune do you have? Trifecta, BNR, ZZP etc.?
BNR tuned. I think I have found the problem after learning more about fuel trims and sensors.
Both oxygen sensors drop to 0V sometimes, very briefly. This causes the computer to add heaps of fuel as it thinks it's extremely lean, which is the short term spike. Then the sensor voltage goes back to normal and long term drops to lean it out again, and gradually goes back to normal. This cycle just repeats itself.
So I need to figure out why the sensor voltages drop to 0V. Both of them do at the same time. I'm guessing a short circuit or bad voltage supply to them both, they must be wired together somewhere.
Well that's all assuming I'm correct, lol...
 

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I have been trying to contact them for quite some time. No answers from anyone via the forum or the website. If you are able to get through to them, ask them as they should be able to help you.
 

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Discussion Starter #8
Oh, ok. The last I heard from customer support was ten days ago. Been waiting two weeks for a response from datalogs. Jerry has been active on Facebook. I emailed customer support this evening with all this info to add to my ticket...
 

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Discussion Starter #9 (Edited)
Anyone know the O2 sensor PIDs? I'm assuming O2S11 is the pre-cat one (bank 1, sensor 1. There is HO2S11 which looks like the post-cat sensor. But I'm uncertain because O2S12 should be bank 1, sensor 2, however there are no values in the computer. Also O2S11 and HO2S11 are almost identical. I'm running a catless downpipe so this makes sense that they're so similar...

EDIT: just found out O2S11 is the SAE standard PID and HO2S11 is the GM PID. They are both measurements of the same O2 sensor...
 
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