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Old 06-21-2013, 02:15 PM   #1
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Default Hot start issues with MS3

Hi guys,
I've been having this issue randomly, but more often then I think I should.

If I start the car 5-10 minutes after driving for a while (like getting gas, or stopping at a local store), I get high rev idle that goes up and down between 2300 -1800 RPM and just keeps doing that until I turn the car back off and restart. Sometimes have to restart 2-3 times before it corrects.

Attached is a datalog of the issue.

Anyone have any ideas?
Attached Files
File Type: msl 2013-06-20_19.14.18.msl (72.8 KB, 64 views)
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Old 06-21-2013, 02:21 PM   #2
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your oscillation seems to be caused by acceleration enrichments. it looks like you are using mapdot instead of tpsdot for enrichment.
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Old 06-21-2013, 02:27 PM   #3
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Here are my settings.
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Hot start issues with MS3-accel.jpg  
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Old 06-21-2013, 02:56 PM   #4
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use the accel pump, but those settings dont like that would cause oscillation...I'd have to look at the log later.
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Old 06-21-2013, 03:13 PM   #5
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Sounds like you have high cranking PWM duty, which gets you high enough RPMs to get stuck in overrun fuel cut - no cut - cut - no cut. Reduce your cranking PWM duty values when warm.
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Old 06-21-2013, 03:34 PM   #6
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Quote:
Originally Posted by Reverant View Post
Sounds like you have high cranking PWM duty, which gets you high enough RPMs to get stuck in overrun fuel cut - no cut - cut - no cut. Reduce your cranking PWM duty values when warm.
Thank you, That makes sense. I see the fuel cut light in tunerstudio when this is happening.

Before and after attached. Look correct? I'll test it this weekend and check back.
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Hot start issues with MS3-crank.jpg  
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Old 06-21-2013, 03:39 PM   #7
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what idle duty do you normally idle at after the car is warmed up?
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Old 06-21-2013, 04:28 PM   #8
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Quote:
Originally Posted by Braineack View Post
what idle duty do you normally idle at after the car is warmed up?
I'm using closed loop idle, "Idle Open Duty(%) = 80"
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Old 06-21-2013, 04:31 PM   #9
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that's not what I asked. That's the maximum duty cycle that closed loop will be able to drive the valve. What I want to know is what duty cycle does the MS typically demand from the idle valve to maintain your target idle speed once the car is warmed. hint: you have to log it or look at the idle pwn% gauge.
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Old 06-21-2013, 04:35 PM   #10
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Rev,
Which did you want me to change:

Cranking Pulse

OR

PWM idle cranking duty
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Old 06-21-2013, 04:40 PM   #11
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Quote:
Originally Posted by Braineack View Post
that's not what I asked. That's the maximum duty cycle that closed loop will be able to drive the valve. What I want to know is what duty cycle does the MS typically demand from the idle valve to maintain your target idle speed once the car is warmed. hint: you have to log it or look at the idle pwn% gauge.
I have a log available to view. What "value/code" do I need to select form the graph choices to get you the info you are asking about?

PWM Idle duty?
Duty Cycle1?
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Old 06-21-2013, 04:53 PM   #12
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Reduce the PWM idle cranking duty.
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Old 07-05-2013, 12:19 PM   #13
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This has helped a tremendous amount. Now just to fix the cold start timing issues.
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