What determines which timing table is being used in a tune?

I've been tuning for many years and can't help but wonder if another platform is responsible for this because that's the only time I've seen something like this happen. I'm specifically aware that there are tables that LS1 edit provided access to that this platform does not. In this case, it was a Diablo hand-held that had been plugged into it before. What's happening here is that the calibration file is not referencing timing from the main spark table while driving, rather the Idle Spark Advance>In Drive table. I know this because of the values that I have in each table and when changing the ones in that table, it affects the result while nothing in the main spark table affects anything. I'm aware of the "Main Spark Table Select" values and left them stock as well as tried changing them to no avail. I'm not aware of anything in the file that will cause this. Anybody else ever experience this and discover what's going on? Maybe one of you guys experienced with hex editing these platforms? File attached for your review.

Does the computer know that it's in gear or does it always say park??

Also you need to set the MAF dtc's to fail on first error for speed density tuning.

I forgot to mention that I did confirm the PRNDL switch is reading and the Trans Current Gear reflects the gear it's in. I even see the idle advance populate at a stop and then disappear once the car begins moving. As far as setting DTC's, I mean no disrespect when I say the following: I've literally tuned at least a couple hundred Gen III's in SD without any known issues so my question is: as long as the car will start, the MAF fails and the engine acts as it should, what's the difference? I've had better luck with setting the DTC's one way versus another, depending on the OS and so I do it accordingly. I'm not saying I'm right. I'm simply sharing my experience. Thanks for the reply.

Well, as you know, its only the "intake manifold changeover" values that cause it to switch away from or to the idle tables... But, if its really in the idle tables then (since its apparently blown?) some nasty things might happen... are you sure its not in the low octane table? Thats where it'll be initially after being force-failed to SD, and if the KR parameters are off it might take a long time to drag itself up to the high table.

My own ECU was previously tweaked with a Diablo HH but it didn't cause any effect like that...

EDIT: BTW, why is the high rpm disable in airflow >> dynamic set to 8k? That would be more or less saying don't use the MAF?

Quote:

---

Originally Posted by dermotw

Well, as you know, its only the "intake manifold changeover" values that cause it to switch away from or to the idle tables... But, if its really in the idle tables then (since its apparently blown?) some nasty things might happen... are you sure its not in the low octane table? Thats where it'll be initially after being force-failed to SD, and if the KR parameters are off it might take a long time to drag itself up to the high table.

My own ECU was previously tweaked with a Diablo HH but it didn't cause any effect like that...

EDIT: BTW, why is the high rpm disable in airflow >> dynamic set to 8k? That would be more or less saying don't use the MAF?

---

When you say "as you know, its only the "intake manifold changeover" values that cause it to switch away from or to the idle tables", I have never heard or read that anywhere and so you've got me quite curious. What is it that you're talking about here?

High RPM disable 8K? Correct, don't use the MAF. This vehicle stays SD. In my experience, vehicle speed thresholds for idle airflow vs throttle cracker have enabled/disabled the idle routine. I've paid specific attention to this, logging STIT's and they won't ever work before the Follower and Cracker have decayed fully. High and low tables are the same. I'm logging everything that should affect timing. Torque management in both the engine and transmission are not in play, Burst Knock is disabled, COT, and Cat Lightoff are disabled. The IAT and ECT corrections are not involved, nor is any knock. All should be apparent within the logs attached.

I mean this, in spark >> advance, which HPT have helpfully just changed the name of in release 3.6 to another non-relevant inaccurate name (the heading name hasn't made sense as long as I can remember);

Attachment 70097

These settings decide the point at which it switches between idle tables and main spark tables (or if it switches at all, depending whats there)... Hover over the entries, you'll see...

Why in the hell a factory calibration would have the main spark table disabled full time is beyond me. I appreciate the input.