help with spark map
10-24-2004, 08:35 AM
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help with spark map I made a calculated pid with efilive to show g/cyl vs rpm to map spark. I notice most don't match with what my hi-octane tables show. Any ideas what I did wrong? I'm trying to figure out what table the car is idling on but none of them seem to match. Kinda at a loss right now. Also, does anyone know what increments timing is increased on the tables in the rpm gaps. Say between 1200-1400 rpm ( not that i'm idling there, just an example). Say timing goes from 26 degrees to 30 degrees in those 200 rpm. How does the timing increase across those 200 rpm? Not sure if that makes sense or not. 
Last edited by 0rion; 10-24-2004 at 08:44 AM.
10-24-2004, 09:23 AM
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There should be a Dynamic Cylinder Air (or similar)
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.
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.
10-25-2004, 12:48 AM
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Thanks for the reply. Not much makes sense with the way this car idles. MAP is in the 60kpa range which is normal for a H/C car from what I understand. Idle's in the .18-.19gms/cyl range at 950 rpm and timing is at 16 degrees. The car has a bad surge until it goes to closed loop then it smooths right out. At an 825 idle it was seeing 12.5-13 degrees advance. I'm just trying to determine where it's referencing timing at. Definately not the hi-octane table because timing would be double that. I'm guessing the base spark in park table but even then the timing doesn't add up. I've taken some out of the ve table but I think some of his problem lies in the timing too. He also has an iac problem. His blade has been drilled but his iac steps are at 160 all the time. It's a fly by wire car so no set screw adjustment for iac. I'm having trouble figuring out if this is a tuning issue solely or maybe his iac motor is shot. He also has a descreened MAF which I wish he didn't have so that I knew all the air was being reported correctly to begin with.
10-25-2004, 08:56 AM
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I just went through this kind of thing (by mail) on a
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.
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.
10-25-2004, 10:29 AM
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Wow, thanks for the in depth response. His IAC max value in edit is 160 and from the time you start the car until the time you turn it off it's sitting on 160. The fact that it surged in open loop and didn't in closed made me think it's a fueling problem. He was also getting a rich code when slow cruising. I scaled the VE up to 1600 and the rich code went away but the surge didn't. Overall the car runs really strong, just that first 2-3 minutes of startup until it goes to closed loop. I'll keep plugging at it and I'll stumble across the problem eventually. Thanks for your help.