Twenty Thousand Degrees Advanced

[JeepsAndGuns]

I remember something like this happening to me once. If I remember correctly, I changed a spark advance setting, maybe a bias setting, and did not reset the ecm before I installed the chip and run it.
I just remember the spark advance number on my ADX jumping to some crazy stupid number and it running like doo-doo.
I have no idea if this has anything to do with your issue, but just figured I would share.

[RobertISaar]

i get the feeling that the spark is being reported as a 16-bit value but someone never set the box for signing.

23,000/.35 = 65,714, which is right around the 16-bit limit, indicating spark is happening negative to reference(or TDC, i don't know the late TBI code too well).

[ericburgundy]

I think Robertlsaar is on to something.
It makes sense that the ecu would try to retard the timing, but then mis-interperet the negative data.
It also makes sense that super-retarded timing wound backfire the intake.
Would a ADX make difference here?
Could you guys suggest/link one for my $OE bin?

[steveo]

lets see the adx you're using it can probably just be fixed

also i really dont see why the calibration shouldn't be set up to clamp timing to 0 degrees minimum anyway. since when has a car engine actually wanted spark after top dead center?

[RobertISaar]

lowish RPM, WOT with a quick throttle transition to get there(triggering burst knock protection or torque management in the process)?

i could see it going ATDC from that.

[ericburgundy]

how do i upload my ADX to this thread?

[1project2many]

If you click "go advanced" you'll be able to attach it as a file. Or send it to me and I can attach it.