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?

your oscillation seems to be caused by acceleration enrichments. it looks like you are using mapdot instead of tpsdot for enrichment.

Here are my settings.

use the accel pump, but those settings dont like that would cause oscillation...I'd have to look at the log later.

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.

what idle duty do you normally idle at after the car is warmed up?

I'm using closed loop idle, "Idle Open Duty(%) = 80"

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.

Rev,
Which did you want me to change:

Cranking Pulse

OR

PWM idle cranking duty

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?

Reduce the PWM idle cranking duty.

This has helped a tremendous amount. Now just to fix the cold start timing issues.