EFIDynoTuning Forum

Ok ... dipping into the realm of ignition timing and spark.

Of course, Perload = 0 and I have FN035 99% dialed in. Did a few WOT runs last night with the supercharger bypassed and saw some spark figures showing up under SAFTOT in the logs that were a bit confusing. For reference, i set up FN2200 pretty conservative to start, knowing that for the last 6-7 years I've been running timing locked out at 19 degrees (at the distributor, spout removed) so I know that Max Timing is safe with the fuel I use and the supercharger pushing 9-10psi.
Here is a screenshot of a section of my exported log from last night's WOT run ... Where I expected to see nothing greater than 19 degrees of advance ... I'm seeing between 20 and 26 degrees of advance. My understanding from reading was that the ECU uses the lowest calculated spark at any given time so something is not making sense. The SPK_Source Payload is telling me that Spark is coming from IDLE FBS and Borderline (9 & 2). I could understand IDLE FBS spark coming in higher as I had not dialed that table down. But the lowest calculated spark should be FN2200 ... what am I missing?
As always, thanks in advance!

perload is for fuel has nothing to do with spark

spark comes from load

26 degrees means your at .65 load up top

also the exported column view is pretty useless, its best to post a screen shot of the dash at the area/time of concern so you can see everything

Ah ... Should have caught that. Thanks!

Following on my Spark related questions ... reviewing logs and doing my best to understand the way in which CBAZA and T4M2 manage timing advance. I think I've got a handle on MBT/FN2300 and Borderline/FN2200. I can see in the logs where each is being activated and have interpolated to confirm the spark values that SAFTOT is showing me. My question is around FN2600/Spark Sea Level ... or what I am coming to understand is or has been converted into a table for Decel Spark. I've noticed that in Decel, where throttle is in the closed position ... the SPK_SOURCE flips over to 1, which from the payloads writeup is the Base Spark Tables.

Now seeing as FN2110 is maxxed out at 60 across the board, my inference is that FN2600 is the table being used when SPK_SOURCE = 1. Is that correct?

Now I am also seeing examples where when cruising at very light throttle, basically just covering the accelerator pedal there are also instances where SPK_SOURCE = 1 and SAFTOT is usually 1-1.5 degrees above the value it should be in the FN2600 table. From what I've been able to find and read ... this seems to be some sort of 'anticipation' of spark required for acceleration about to happen and is possibly connected to FN1036A/Inferred Load. Is that right?

If so ... using the N_TP_TOTLDSTErr histogram to dial in FN1036A should address any misalignment between Load, Inferred Load and PERLOAD, yes?

Finally, and may or may not be related ... AEFUEL/SP_AEFUEL ... are these connected to Inferred Load/FN1036A? Acceleration enrichment or anticipating Lambse for a potential tip-in or tip-out?

no such thing as spark anticipation, if it doesn't match 100% then your skipping over some modifier somewhere

not sure what spk source i have for the decel spark table but its only active at closed throttle

fn1036 is where inferred load comes from TOTLDST as logged just under load on the dash. Perload has nothing to do with any of that it comes from FN035.

AE fuel does not exist in cbaza that's older strategies such as GUFX, speed density and the like.

Manifold volume replaced accel / tip in enrichment in all newer strategies from 1993 to 2025.

No such thing as anticipated lambse.