Is there really a purpose for this? I understand, if idle for some reason is over by xxx rpm error it reduces spark. But why keep it? Seems better to zero out the table and re-adjust mini air. ??

It drives me nuts when I look at my logs and question why the numbers are not what they are supposed to be.

-- Joe

 

The IAC provides a course adjustment of engine idle speed and the idle retard/advance provides a finer adjustment. The IAC won't even move on the stock calibration until the rpm is 50 rpm above or below the commanded idle speed. (Idle deadbands park/neutral and drive are 50 rpm). Varying the spark advance causes the engine to do some weird things, if you are not using the stock idle timing amount. You may have to re-work the tables to suit your needs. My engine running vortec heads liked the stock vortec tables and likes more variation at higher loading (a/c on and drive). When the engine loading is lower it takes less timing to get the desired result. If your engine is surging like mad with the stock settings, change the multiplier in the area you are seeing the problem. Stock is 1.00 in all multiplier settings. You have two advance and two retard tables to work with. The first is timing retard/advance against rpm error and the second is a multiplier vs. map.

 

I don't understand why you would want that though. It seems to me it would be most logical to zero everything out and just run static idle timing based on RPM. In my case, 24 degrees total unless in the upper RPM's than 26-32 degrees. The fluxuating timing is only making a slightly lopey cam worse.

-- Joe

 

Anesthes, I zeroed out my idle steps at idle so I also zeroed out my idle speed spark correction tables as well. It seems to work just great like that- rock steady idle even with or without the A/C running.
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Fast, what are the titles of those four spark advance correction tables? The titles are truncated. I believe Tunercat has the bottom two idle speed spark advance and retard tables but not the other two. I'd want to send an e-mail to Tunercat to have the other two added.