I apologize for the noob question, but could someone explain how the spark tables work in EFILive? There is a high-octane table, low-octane table, optimal spark table, and base spark table, and maybe more. At highway speed at lowish RPM and moderate TP I am getting some knock retard and I'm confused as to which table I need to be looking at. Also, during normal cruising and fully warm, my spark does not match any of the tables. It's close to the high-octane table but usually 1-2 deg below. Could be due to interpolation I suppose.

When knock retard occurs, how is the new spark calculated?

Feel free to post a link, I couldn't find one

Thanks!

 

Final spark is controlled by a number of factors. Look through all the tables and you will come across them, iat, ect, etc. You can log the spark scalar in the scan tool to see what percentage of the high spark table you are using.

 

Is that the same log that you emailed me?

I just go in and remove timing from the low oct and high oct tables. that usually cures it.

 

Post up your tune and any logs please.

 

You mean subtract from the entire table? I was trying to pinpoint the problem area and got sidetracked by the fact that the actual spark didn't match what was in the tables. Figure I should understand how spark is calculate before I go and change things.

Yes the ones I sent you. I also flashed in a stock tune this morning (with some adjustments for the T56 swap DTC's, idle, and fans), reset the LTFTs before setting off, and still got some knock retard, albeit not as much. I'm running 87 octane though.

Is having the low-octane table 8-10 degees lower than the high-octane table a good rule of thumb?

 

In HPT the final spark is calculated my interpolation (average in this case) of the high and low tables. I find this annoying so I just copy and paste the high table into the low table so they match.

 

Tune and logs from this morning are attached.

0006 is a long drive to work, a couple spots of KR, nothing exciting. I took it easy because its a stock tune.

0007 is a short idle when I got to work to look at my O2 sensors because someone said they were acting funny. As in not switching fast enough, inconsistent switching, lazy, etc. They only have 10k miles on them though.

 

That burst of KR looks false to me. 1700 rpm 30% TPS is putting some load on it, its probably picking up some valvetrain noise. Get a wideband on it to confirm AFR.

That stock tune has your timing in the dumps. It's anywhere from 11-15* at WOT. You're beyond the expected airflow for the stock cam and in the lower part of the timing table. Get a wideband on it, do AutoVE and get the timing around 23-24 degrees. You will see a significant performance increase.

 

Thanks for the tips. I reloaded a mail order tune I got and made minor tweaks to, and logged my drive home. There is a WOT run in there and a bunch more knock on the highway, including some interesting ones towards the end. I also logged GM.ASPARK and interestingly it was 100% the entire time even when in KR. I should add that when I go WOT on the highway I can sometimes faintly here the sound of pebbles in the beer can from the engine.

Could this be burst knock retard? Is burst knock retard unavoidable?

I do have a wideband but it won't be going until until the turbo does.

 

The low and high octane tables are identical at a glance. I would put the low octane table back to stock.

Also, I didn't see anything in that log convincing for real knock. But without an AFR reading I can't say that for sure. Your B6245 table is set up with the knock sensors overly sensitive, in my experience.