Disabling MAF and defaulting to Spark Low Octane table only?

[guyomatic]

My MAF is disabled as I'm running a boosted set up, is it true then, with a disable MAF that the VCM defaults to Low Octane table only for spark?

the FAQ states;

'Main Spark Tables
The VCM constantly looks up both High Octane and Low Octane spark tables and interpolates a value between the two tables based on the current Knock Learn factor. If the engine has been operating for a moderate time without any Knock Retard then Knock Learn is zero and the interpolation favors the High Octane table, if Knock has been detected then the interpolation will move towards the Low Octane table. During MAF failure the Knock Learn is set to maximum and the Low Octane table is used (HP Tuners speed density enhancements allow both spark tables to function).'

So the last part 'enhancements' using both??

Just a confused newbie. thanks,

[1BadSlug]

That is actually a very good question. I believe it's always running off the high octane table.
Unless the engine lights on and or knock detection is active then Low octane is introduced.
I man be wrong, but I'm certain this is right.

People run SD all the time.

[Matt Vardaman]

Log the Knock learn factor. Mine is using the High Octane main spark when it's at a value of 1.0. When I was working out the timing and getting very mild spark knock, the value would move to .98. If no knock occured in the next few minutes of the log, it would move back to 1.0. So on my 2001 truck 0 is low and 1.0 is high octane. I've verified with spark advance log.

[Carlfromkerikeri]

If you have failed the MAF properly it will be running on the low octane spark table, which is why when tuning SD VE table you need to copy the high octane to the low octane table, if you complete a 2 bar OS enhancement it then allows to operate the high octane spark table with the low octane spark table as the safety measure. Check out goat rope garage videos on you tube as he has some really good gen3 tuning information

[guyomatic]

I'm running;
Operating System 12587811 -> 1250062
Speed Density - 2 Bar
Security Key (OS Mod Locked)
on my P59 ECM GM Gen 3
Is there another thing called 'OS Enhancement' or am I good to go with both tables with a failed MAP?

[kevin87turbot]

Your OS should allow for use of both tables. It'll be a simple check...does your Knock Learn vary...or does it stay at 1?

[guyomatic]

Your OS should allow for use of both tables. It'll be a simple check...does your Knock Learn vary...or does it stay at 1?

Right now, it stays at 1, but I'm just idle tuning right now, waiting for the 'pro link' cable to connect my AFR. I just installed my Injector Dynamics ID1300x2 and got it started and running, but obviously it needs some serious tuning!! thanks for the help!