Help me tune my car
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Joined: Sep 2003
Posts: 98
From: Wylie, Texas
Help me tune my car
I'm getting ready to tune my ECM for the supercharger that I installed myself. I have a 30 minute datalog that I took one night on my way home from work. The log starts from a cold start and covers my cruise home with a few WOT runs near the end of the log file. I have never tuned an ECM before but I have been studying the subject for a while now. I am using tunercat, but so far I have not changed any of the fuel tables or spark tables. I would appreciate any advice from anyone that has tuned an ECM before. Currently I am only interested in tuning the cruise speeds, as I have not had it on the dyno yet to get my real A/F ratio at WOT. Here is my analysis of the data:
csv log file is here
1. The O2's seem a little odd at startup but I attribute this to the fact that they are not heated at that point. But I find it odd that one goes high and the other goes low to begin with. I assuming this isn't a big deal since I am still in open loop at this time.
2. The iginition timing advance seems to average around 38 degrees BTDC during a steady cruise at 70MPH. But what surprised me was how much it jumps around during the cruise. Anywhere from 10 to 45 degrees. Is this normal?
3. The LTFT is still within the limits, but averages around -7 to -8 percent during cruise. I'm thinking I could subtract a little from the VE table in cell blocks 6 through 10. Does that sound about right? How do you know how much to subtract?
4. During cruise the log shows some know retard which I wasn't really expecting. Doesn't seem to be pulling much however.
5. During WOT runs I see knock retard jump up as much as 10 degrees. But the overall timing advance is around 25 degrees BTDC. Any recommendations for the spark advance table for this supercharger application? I've read that a FI application doesn't need as much advance since the air is so dense. Also does my knock count look average, or should I be worried?
6. Another odd thing is that the knock retard seems to occur at times when the knock counter does not increment. Why is that?
csv log file is here
1. The O2's seem a little odd at startup but I attribute this to the fact that they are not heated at that point. But I find it odd that one goes high and the other goes low to begin with. I assuming this isn't a big deal since I am still in open loop at this time.
2. The iginition timing advance seems to average around 38 degrees BTDC during a steady cruise at 70MPH. But what surprised me was how much it jumps around during the cruise. Anywhere from 10 to 45 degrees. Is this normal?
3. The LTFT is still within the limits, but averages around -7 to -8 percent during cruise. I'm thinking I could subtract a little from the VE table in cell blocks 6 through 10. Does that sound about right? How do you know how much to subtract?
4. During cruise the log shows some know retard which I wasn't really expecting. Doesn't seem to be pulling much however.
5. During WOT runs I see knock retard jump up as much as 10 degrees. But the overall timing advance is around 25 degrees BTDC. Any recommendations for the spark advance table for this supercharger application? I've read that a FI application doesn't need as much advance since the air is so dense. Also does my knock count look average, or should I be worried?
6. Another odd thing is that the knock retard seems to occur at times when the knock counter does not increment. Why is that?
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