Hi,

I am working on tuning my 355 LTR setup.

I need to add some SA during cold coolant temperature conditions to keep the engine running well. At least long enough for the water temperature to approach the 180 °F nominal running condition.

I have finally locked-in the normal operating temperature SA vs. Load vs. RPM table.

Now I am working on the "Cold Temp Start-Up" Spark Advance optimization.

Ignoring the details of the Start-Up Spark Advance Decay-Delay and Spark Advance Decay time properties (working fine), it is my understanding (from reading the HAC) that the total SA is determined as follows.

1.
Look-up the "base" SA based on Load and RPM (2D Table).

This table works great for nominal coolant temperatures (180°F).

2.
Compensate the "base" SA based on Coolant Temp vs Load (2D Table).

3.
Add the Start-Up Spark Advance offset as a function of Coolant Temp
(1D Table). This value is decayed out long before the coolant temperature increases significantly. Just a start-up mode event.

Based on the TunerPro RT data log, it looks like the SA compensation as a function of Coolant Temp vs Load was not included.

???

Is the above reasoning correct?

I dug a little deeper into the HAC and found an interesting parameter.

Address : 0x2B : Disable Cold Spark Advance if Coolant is > Threshold.

The present parameter value is -40 °F.

Does this parameter act as an override to the SA Compensation vs. Coolant Temp vs. Load Table for temperatures below the threshold?

I also found a Hot Spark Retard parameter at address 0X29. It looks like this parameter enables a hot restart SA retard if the Coolant Temperature is > a programmed threshold.

Any help would be much appreciated.

Best Regards,

Bruce