tici

iTrader: (1)

As in the title: how does the PCM decide the actual timing?
After a very long scan I put the average timing in a G/Cyl vs. RPM pivot table and compared the result with the high octane spark advance table.
My expectation was to see measured values lower than the table in the PCM, something between the high and the low table…
In general the values are lower than the high octane table, but in certain spots they are up to 6* higher.
And guess where I have the most KR? Exactly there!! Between 1200 and 2200 RPM and 032 and 052 G/Cyl.

Hope someone can explain this

Thanks - Stefano

jimmyblue

iTrader: (11)

Quite likely the EGR adder table is throwing down some
extra advance when active. If the EGR is still in place
this is proper (but if it's causing you ping, you might
want to take out some of that table's advance).

tici

iTrader: (1)

EGR is still there, where can I find this table?
I'm using Edit version 1.5 for my 98 PCM

jimmyblue

iTrader: (11)

I don't know about Edit. In HPTuners it's in the Engine>
Spark Advance section, EGR Correction - Add

tici

iTrader: (1)

I only see "Base Spark Table, Closed Throttle in Drive". ???
Nothing about EGR and timing
I guess I'll have to work with the high and low spark advance tables.
I reduced them once and the KR almost disappeared, I was just pissed to see the PCM adding timing and then having KR exactly there.