Odd spark behavior in SD

I have concurrently developed the same tune to run CL with MAF and OLSD (DTC confirmed) and have noticed significant erratic spark behavior in SD not present with the MAF-enabled version. It is very apparent in the logs and while driving. I first noticed under high load, the SD tune selecting lower spark values as if pulling from the low-octane table but ASPARK is 100% for BOTH in the logs under the same conditions. Now, I see it is happening in all conditions. As a result, the CL tune feels smoother, especially under load and pulls harder because the spark is consistently following the high-octane table.

The photo shows a short SD log and just after frame 1150 you can see where the anomaly starts. This is the first time I’ve seen it change from smooth to erratic. It is so significant in light load situations like the one just after frame 1610 that it feels like a misfire.

Try to copy Hi octane table to low octane table.

I really didn't want to do that so, I thought, what if I switched the MAF DTC's from Non Emissions to Not Reported? It seems to have worked.

2nd SD log with no spark issues... Looks like it's fixed.

Quote:

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Originally Posted by robof16

I really didn't want to do that so, I thought, what if I switched the MAF DTC's from Non Emissions to Not Reported? It seems to have worked.

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It was just a test.

oh... Cpy.
Thanks for the replies.

Since it changed during the posted log, as the truck warmed up, I thought it could be ECT related but apparently not.

I dont see a log that was posted.

I meant the photo attached to the original post

Its hard to look at a picture of a log. Uploading it helps a bunch.

I never considered setting "Not Report" for MAF fail, I always just mod the low octane table. That's a tip I'm going to have to try.

I was just experimenting trying to keep the low/high octane table functionality you get with COS3/5. The COS upgrade tutorial and all the recommendations I've seen say you have to have a DTC with the failed MAF but I have confirmed everything working correctly with "not reported", even the log showing "CL" mode while in semi-closed loop, and the transition to "OL" when tripping PE. The tutorial also says you have to go MAFless when running a 2 or 3-bar MAP sensor and I've confirmed that is not the case.

Fixed, smooth, as-commanded spark
Two things:
1. Burst Knock Retard was the culprit. Zeros in B6212, and maximum value in B6208 to disable. Somehow, running in SD triggered Burst Knock.
2. I was incorrect about being able to set P0101-P0103 to "Not Reported" and run SD, you cannot, just like the instructions say