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Old Feb 24, 2020 | 06:03 PM
  #1  
andym's Avatar
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Default Startup Idle Issues

Hi guys, I've been tuning my car for about a year now. For some reason I can't consistently get my car to start. I've tried messing with damn near every parameter I can think that would affect startup and my overall conclusion is that nothing i've tried has had a substantial impact. On my datalog taken seconds apart from each other on the same tune I have conflicting starting problems. In datalog 1 the car starts fine and slowly settles down to target rpm. On datalog 2 the car starts then has a sudden dropoff on IACV % to almost my minimum value range then it shoots back up then tries to drop again then settles back down. I can't figure out what would cause this to happen on 2 back to back attempts.

Attached is my tune and both datalogs.

.
Attached Files
File Type: mlg
idle stumbling.mlg (152.2 KB, 58 views)
File Type: mlg
idle stumbling 2.mlg (126.8 KB, 97 views)
File Type: msq
Andy 4.96.msq (275.4 KB, 53 views)
Old Feb 24, 2020 | 08:53 PM
  #2  
DNMakinson's Avatar
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Default

I don't have the high $$$ Megalog viewer, thus I cannot open the mlg files.

If you are willing, go into TunerStudio and go to Options / Data Logging Preferences / Data Log Format / ASCII
Then take new logs in .msl format, which I can open.

DNM
Old Feb 24, 2020 | 09:05 PM
  #3  
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Attached are the same logs just converted to the file format you requested.
Attached Files
File Type: msl
idle stumbling_modified.msl (282.9 KB, 57 views)
File Type: msl
idle stumbling 2_modified.msl (233.2 KB, 59 views)
Old Feb 24, 2020 | 09:39 PM
  #4  
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I guess I just needed to update my MLV? Both kinds of files open now.
What is happening on the bad one, is that you are falling out of CLI. Turn on Status 2 (or look at it in the bottom section) and you can see it. S2 = 132 is CLI engaged.
1st thing I'd try is to change CLI PID Delay from 1 to 3. Even though this should not be involved, being less than 3 does indeed cause seemingly random CLI engagement issues. It is a pain to have to wait every time you stop, but it is more repeatable.

I don't see anything else causing you to go out of CLI.
Old Feb 24, 2020 | 10:31 PM
  #5  
andym's Avatar
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I tried what you suggested and that seemed to help in addition to some other tuning efforts I made. Stalling right after startup is no longer an issue. I did however come to find out that my pid tuning needs some attention. Everything I thought I knew about pid tuning seems to be not entirely right with respect to my tune. So I will be re researching how to tune pid again.

For reference this is the current state of my tune now.

Attached Files
File Type: msq
Andy 4.9616.msq (275.8 KB, 53 views)
Old Feb 29, 2020 | 11:09 AM
  #6  
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Woah, that's a crazy amount of D. What are you trying to solve?
Old Feb 29, 2020 | 07:57 PM
  #7  
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To be honest, I am not sure. PID tuning is not my forte. I was changing the values arbitrarily until overall car idle stability felt improved.
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