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EQ Err sd graph not reading

Practical Reflash Tuning

Discussion and questions related to the course Reflashing

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09 Silverado 6.0L 1500/E38 ECM

After getting my afr dialed in using just the maf sensor while following along with the course step by step. I'm now working to get the ve tables set and I'm not getting any data readings on the EQ Err sd graph you set up. I set mine up the same as you did in the course and I think I have the same channels set in my log file. I noticed your long term and short term fuel trims are disabled but you didn't mention to disable them while changing the file after the maf calibration step. Do I need to disable the LTFT and STFT? Are the numbers in the EQ Err graph generated from the wideband and that's why I'm not getting a reading with the EQ Err graph? I'm stumped on why it not working as I followed along every step multiple times. My combined fuel trim were working and was reading around -40/-20 at idle with check engine light illuminated on the dash. Does the check engine light actually illuminate on the dash while tuning in this step or Am I doing wrong??

Hey Peter, are you actually getting data from the EQ Error PID in the channel list? That's the first thing to focus on and this can be due to you logging the mixture in AFR units rather than lambda - There's a separate math channel for the error for each and this can trip you up. The EQ error parameter is a math channel and requires a valid wideband input to the scanner in order to generate the channel. This may be your problem I think.

If you're using the EQ Error math channel then the fuel trims need to be disabled otherwise they will drive the AFR to target and it will look like your error is essentially zero. If your combined trims are beyond +/-255 for sufficient time you will end up getting a CEL for bank 1/2 too rich/lean. you can check the reason for the DTC in the scanner and rest it. Under normal circumstances you shouldn't have a DTC on at all.