Start-up Fuel and ISCV Tables
#21
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I had PM'd you, i would like your services to help me clean up some roms i have..
#22
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Has anyone found a way to adjust the Post-Cranking IPW adder "decay" time? This would really help with lean hot starts on SD ROMs, as a mask for a heatsoaked IAT. It seems to decay out too quickly for what I need it to do.
#24
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It's located at the edge of the engine bay where the FMIC outlet piping enters the engine bay. I thought this would reduce heatsoak but I still see 120-130F IATs before starting if the car's been sitting hot for 15-30 minutes. Once air starts flowing and IATs come down, it's fine. It's also fine if I lock IAT at 75F as a test.
BTW, awesome writeup/diagrams! I sort of figured this stuff out by trial and error after a while but it's very helpful to have a visual diagram of it, which I had this months ago!
Beau
BTW, awesome writeup/diagrams! I sort of figured this stuff out by trial and error after a while but it's very helpful to have a visual diagram of it, which I had this months ago!
Beau
#25
Thanks Most of the stuff was already found except for the 'Post Cranking ISCV Adder' which I came a cross accidentally while looking for something else. That to me, was the biggest find since its VERY helpful. As far as I know, that table hadn't been found before or at least labeled with what it did. Same with the Post-cranking IPW Adder. It was found but no one had the correct labeling or had figured out the correct scaling. Now we have a good base to build from.
I would like to track down the decay timers too.
-Jamie
I would like to track down the decay timers too.
-Jamie
#26
I have also noticed that the datalogged 'Target Idle' is higher than the 'desired idle' table in ECUflash for the first 15 or so seconds after startup sometimes, then decays back down to the 'desired idle' parameter. I would liketo find that table as well. It's probably an RPM adder.
-Jamie
-Jamie
#27
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You can do a couple of things pretty easily as a band-aid fix:
1. Cap your IAT table, similar to how you said you locked your 75F.
The reasoning for this is because your probably only seeing those higher temperatures because of heat soak while the car has been sitting. If you do happen to see those high temperatures during a run, you'll simply be adding a little more fuel and running richer, which is a little bit of a safety measure anyway.
2. Use the fuel temp as the IAT input. You won't be getting accurate intake temps, but you can tune around it based on your IAT profile and rise through a run. You can tune everything back to how you have it now (AFRs, timing, etc) and not have the heatsoak issue.
#29
Yeah, in the first two posts. Some are already known tables that I just put together as a group and relabeled, though the 'post-cranking ISCV adder' was one that I had never seen posted before, at least not defined. I basically just showed the major settings I found to be the most useful for dialing-in start-ups.
-Jamie
-Jamie
#30
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I asked for an update to the ROM to fix this issue years ago in some other thread. Something like and offset for a period of time at startup to the IAT.
You can do a couple of things pretty easily as a band-aid fix:
1. Cap your IAT table, similar to how you said you locked your 75F.
The reasoning for this is because your probably only seeing those higher temperatures because of heat soak while the car has been sitting. If you do happen to see those high temperatures during a run, you'll simply be adding a little more fuel and running richer, which is a little bit of a safety measure anyway.
2. Use the fuel temp as the IAT input. You won't be getting accurate intake temps, but you can tune around it based on your IAT profile and rise through a run. You can tune everything back to how you have it now (AFRs, timing, etc) and not have the heatsoak issue.
You can do a couple of things pretty easily as a band-aid fix:
1. Cap your IAT table, similar to how you said you locked your 75F.
The reasoning for this is because your probably only seeing those higher temperatures because of heat soak while the car has been sitting. If you do happen to see those high temperatures during a run, you'll simply be adding a little more fuel and running richer, which is a little bit of a safety measure anyway.
2. Use the fuel temp as the IAT input. You won't be getting accurate intake temps, but you can tune around it based on your IAT profile and rise through a run. You can tune everything back to how you have it now (AFRs, timing, etc) and not have the heatsoak issue.
Honestly, I'd most like the ROM to be updated to be more like a true SD system where IAT is a very small factor into the temperature part of the airflow calculation at low airflows (idle). The coolant temp sensor should be used during these conditions anyway. This is why this isn't a problem on most true SD VE based systems.
Beau