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Speed lockout issues? Idle jump.


KcJones
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Hello. I have a 350z with the link g4 plug and play.  Having and issue where after accelerating from a stand still and coming off throttle the idle doesnt drop below 2700 to 2800 rpm. Using closed loop e-throttle. Just looking for some insight before heading back to the tuner

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The problem you've got is that your ethrottle target never drops below 8%. The target vs actual is tracking really well but the target isnt what you think it is.

In the screenshot below you can see your accel pedal is at 0%, and this lines up with the 2.5% in the ethrottle table - giving you the green "base target" of 2.5%. Bottom left corner

The way ethrottle works though is that it adds your base target to you idle base position percentage, and uses this combined value as your "target" for the throttle blade. So... 2.5% from the target table, plus 5.4% from the idle table = 7.9% throttle opening  - see the 8% throttle position. Then closed loop can add/subtract some % too but in your case this isnt relevant for most of the log because your idle is so high you never get below the rpm cutoff.

image.thumb.png.66fbcdaa8cd78c1ee61c1f4d8fc5b6be.png

you need to reduce the numbers in one or both of the idle base postiion table and/or the zero row of your ethrottle target table. I'd typically put 0 as your ethrottle target for the 0% AP row for everything above about 1500-2000rpm, and drop the values in that idle base table to probably more like 1-2% (select the whole table and type "- 3 <enter>" and it should drop all values by 3 points). 

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Thanks for the reply cj.  I didnt have a whole lot of time today but did manage to make some changes that are smoothing my idle out and reducing the "hunting" issue.  But the idle still shoots way up and then surges after the car has started moving forward.  It now only shoots up to around 1700 to 1800 rpm and oscillates up and down.  I believe I have some research to do.

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I've had another look at the start of the logs and where it was idling at 1200 ish near the start, the Closed loop control is at -4.2 to -4.6%. This is "added" to the numbers I described in my first post giving you an idle TP  value of about 3.5% which is sounds normal. Once you do any of the following for a few seconds it exits closed loop idle and never gets back down to it because your open loop idle throttle numbers are still too high and you're stuck above the idle lockout - AP over 5%, revs over 1400, or speed over 2kph. If you can make your open loop numbers (AP target + base idle postition) add up to give you 3.5ish% throttle target then I think you'll find it behaves a lot better.

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Cj. You are awesome. thank you for the help.  I still have some testing to do and a little cleaning but I managed to get the idle to start returning to its target by doing exactly as you said.  I adjusted my e throttle numbers in the 0% ap row to zero above 1500 rpm and lowered the remaining lower columns to 1%.  I also lowered all my base position by 1% across the board. sooo much better but I think I need to jockey those numbers around a little by possibly raising the e throttle a little and lowering the base.  I also adjusted the rpm lockout to 150 from 400 which if im understanding should help it get back to closed loop idle.

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