help with spark map
Last edited by 0rion; Oct 24, 2004 at 08:44 AM.
already in EFILive to pick? Might check that against
your calculated to see how close.
The spark table I expect interpolates between the
values in the table and if you are not dead on (say)
1400RPM you will get something between the 1200
and 1400, and similarly for MAP, values. Then you have
any knock learning driging you between high and low
octane tables, the various ECT, IAT, EGR, ... adders
and multipliers messing you around from that base,
etc.
car with an even higher idle MAP. I found that the
low RPM mixture was uniformly rich, it looked like
the VE table wanted scaling-down all the way up
into the 2000s. This really depends a lot on the
cam and how badly it kills the low end pumping.
I had the guy drive on a special tune that held off
closed loop operation, got a look at the O2s and
took a guess about the indicated AFR (pretty well
pegged high) and made myself a little map of what
the VE table wanted scaled by. Then I applied that
to the table followed by some eyeball smoothing.
Surge in open loop, that goes away closed, is almost
certainly telling you it's mixture. Though there are
also potentially some effects from ECT on spark.
I did also mess around the open loop fuel/air table
because at high MAP, low temp there are some very
high commanded open loop enrichment values which
I suspect were driving some of the richness. I do not
fully understand the open loop mode's enable logic,
however, including whether the OLFA table is able to
mess with idle (but it was ridiculously rich anyway and
the idle / low cruise MAP readings were high enough
to be into 1.3 (11.3:1) commanded AFR territory).
The idle control loop also pushes spark around, if
you are trying to keep idle lower than it likes the
PCM will pull spark out. I also set idle airflow to be
close to what the result, for near-desired-idle-RPM,
logged at, just slightly less, so that they would not
be trying to produce different results or see a big
difference from rolling to stopped idle etc.
What is the maximum IAC step value? I thought it
was much higher than 160. As long as the IAC is
in the "linear" region (not bumping off zero or the
high limit) I don't think the count matters much.
The higher you set the idle the easier it is to get
stable. But 950 is awfully high to be pleasant.

