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High Start Idle & Overrun


wastegate

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Hi Link,

Would like help in understanding what is going on here. I "think" I might have solved it for 1/2 the query but would like confirmation that is the issue/solution.

I've been having an issue with starting the car and the idle will shoot up to 2000-2200 rpm and hold there for a couple of minutes before starting to come down. It's not every time I start the car, maybe 4/10 times. So it's been hard to replicate each time.

Doing to research, watching multiple videos from HP Academy and others, I analysed the logs and saw that my DBW TPS was quite high at 8-9% while APS was 0%. A bit higher than the base idle position of around 7%. I saw startup offset was set to 1.5% so assuming this is what is causing it. But looking at the logs more, the startup offset should be decayed after 3 seconds. But it's not decaying.

What is causing this that I'm not seeing? I can't even seem to log startup offset, hold and decay times. 

There is also a secondary weirdness. Overrun seems to cut in and out during this log, again I can't seems to find a trigger for it..

 

Any advice is welcome cheers.

ECU Tune File
https://drive.google.com/file/d/1bWYckZR-3t-_bbdDq5AtRUnbwyB_w4td/view?usp=sharing

 

ECU Log File
https://drive.google.com/file/d/1IwFA6A-5JVUU_0-eqrVwC2rkDLanSzPZ/view?usp=sharing

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Your idle postion starts at 9.1%, this comes from your base position (7.6%) + your start-up offset (1.5%), you can see the start-up offset is decayed away over a few seconds and at log time -1:36 the idle position is back down to base position.  But Your RPM is still at 1900 at its point - it is above your RPM lockout so idle control will never kick in.  

So your base position is too high for 40°C and possibly your start up offset is too high.   At -1:35 your AC turns on which adds another 0.8% offset and makes things worse but that is probably ok provided the other two were closer to correct.

VBK46BG.png

 

Overrun fuel cut is active because your APS is below the APS threshold and RPM is above the de-activation RPM. 

9cbj9RM.png

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