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Old 12-04-2015, 02:16 PM   #1
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Default Closed loop idle too early?

Ok so I might have figured out my dying issue, but not sure exactly what setting to change.

Whats happening is holding constant throttle, low load it enters into closed loop idle, and tries to drag my idle down. Then when I push in the clutch my rpms drop like a rock (because my idle valve is barely open).

I'm guessing the culprit is PID disable rpmdot, or RPMdot Threshold. What say you guys.


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File Type: msq 12.4.15idleissue.msq (236.5 KB, 38 views)
File Type: msl 2015-12-04_08.34.55.msl (1.06 MB, 57 views)
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Old 12-04-2015, 02:23 PM   #2
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I don't have any help for you, but I want to follow all of the CL idle threads I can since mine still needs a little work.
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Old 12-04-2015, 02:26 PM   #3
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from a glance my guess is: its activating while youre still driving with the TPS under 5%.

On that log you're at 2% TPS, then push the clutch.

Once you hit 5% and met other thresholds, it's trying to close the valve. You can see in your log where the idle speed target kicked in, so you were running CL idle while still driving. Then you actually let off throttle and it's unable to recover fast enough because the MS thought it was already idling, and no dashpot + initial duty gets added now to prevent the RPMs from crashing.

corrective action: tps activation % just above where it sits at idle, readdress initial duties table.
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Old 12-04-2015, 02:29 PM   #4
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Ugh. My tps varies too much. I'll try and lower it some. But depending on the day my base TPS can vary by a few %
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Old 12-04-2015, 02:32 PM   #5
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then add lag factor to the TPS to reduce noise. I see the TPS log hits -5.7%. You have CL idle running while you're techincally at 11% throttle.

a typical setting is 0.8-1.0% TPS.
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Old 12-04-2015, 02:33 PM   #6
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I'll try that. Thanks.

Edit: Its already at 10. Which is "highly smoothed"
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Old 12-04-2015, 02:36 PM   #7
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I set my TPS closed ADC to a few points below zero. And set "Auto-zero TPS" on. We'll see what happens.
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Old 12-04-2015, 03:16 PM   #8
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why so noisey?

something that helps there is rotating the tps in reference to the TB itself so that at idle is not such an extreme point on the variable resistor. you can lossen the two screws holding it in place and rotate it a little so closed might actually be where 10% tps is normally now for you, after recalibration, this might help you find a better working zone for your TPS.
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Old 12-04-2015, 03:18 PM   #9
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Its not as much noise. As changing values on startup. Its relatively stable when running. But some mornings its -3, sometimes its 2. I wonder if my throttle return spring is wack, and its actually not returning to the same place.
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Old 12-04-2015, 03:26 PM   #10
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I've been tuning CL idle on my car for 2 days now, before that no experience at all.

That said, I looked at your log. 2 things stand out that will cause problems

1. TPS does not return to same place every time. Either throttle is sticking (that's a safety problem-fix asap), or TPS sensor is ****, or wiring to TPS sensor is somehow causing problem. My guess is throttle as the log shows RPMs dropping when TPS drops at the end when it dies on you in the log.

2. Voltage dropped when it died at end. Fix 1 and this problem will probably go away. I can say though on my car, I have a 220A alternator and it doesn't like low RPMs, so I'm going to put a smaller pulley on it so I can idle lower without my voltage dropping on me.
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Old 12-04-2015, 03:28 PM   #11
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TPS sensor is damn near brand new. Throttle may be sticking. Whats a good way to check this? Wiring is stock. I could scope the signal and see if its actually jittery/noisy

Voltage drops below like 500rpm. The car is basically dead at that point.
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Old 12-04-2015, 03:32 PM   #12
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Look at the throttle and cable. Either can cause it to not close all the way. On my setup I have 2 throttle cables as I built a cam device to linearize my throttle. I have to leave a decent amount of slack in the cable when cold, else when it's hot the throttle won't close.

Warm car up, drive it, check for some slack in throttle cable. Adjust if needed.

Then with car off key on, zero TPS and then hit throttle and let off, check it. Then slowly apply and slowly let off, blip it, WOT and let off quickly, etc. Try to make it stick. If it does, get out of the car and psychically push the throttle closed, see if it moves. If it does, it's sticking.
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Old 12-04-2015, 03:33 PM   #13
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Quote:
Originally Posted by patsmx5 View Post
Look at the throttle and cable. Either can cause it to not close all the way. On my setup I have 2 throttle cables as I built a cam device to linearize my throttle. I have to leave a decent amount of slack in the cable when cold, else when it's hot the throttle won't close.

Warm car up, drive it, check for some slack in throttle cable. Adjust if needed.

Then with car off key on, zero TPS and then hit throttle and let off, check it. Then slowly apply and slowly let off, blip it, WOT and let off quickly, etc. Try to make it stick. If it does, get out of the car and psychically push the throttle closed, see if it moves. If it does, it's sticking.
+prop. Thanks. I'll tinker with that.
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Old 12-04-2015, 03:35 PM   #14
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Quote:
Originally Posted by aidandj View Post
...
Voltage drops below like 500rpm. The car is basically dead at that point.
On my MS3 PRO, the ECU reading lags on voltage. It's like a smoothed/average value. You might want to confirm on yours.

Also I run 50 Lag factor for TPS. If you got high smoothing that could mask your problem from being a noisy sensor or bad wiring.
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Old 12-04-2015, 03:36 PM   #15
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Battery lag is 90, so almost none.

TPS lag is 10, so very high. I'll scope it out this weekend if i get the motivation.
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Old 12-04-2015, 03:37 PM   #16
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Having a hotside SC setup, I've spent more hours messing with idle and low speed driveability than I care to admit..... But I can say I probably have one of the best idle/low speed stabile hotside SC setups ever just from my brute force throw hours at it.
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Old 12-04-2015, 03:38 PM   #17
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I've barely spent any time on it. I just pop the clutch out and bump start it again, kinda become habit when it dies.
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Old 12-04-2015, 03:39 PM   #18
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Sweet, thanks for that, just saw you can adjust battery lag. Never noticed. Will bump that to 100. I run 100 on MAP and AFR for the quickness. 100 for map helps with low speed throttle response for me.
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Old 12-04-2015, 03:46 PM   #19
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Also your idle setting are a lot different than mine. I'll post mine in case they help you out. I spent about 2.5hrs coming up with these last night. This works really well on my setup, the only problem I have now is my alternator not keeping up below 1,200 with all electrical stuff on (headlights, power inverter, stereo, a/c compressor and fan, two fuel pumps)

This is with a 99 idle valve, 4001 diode across it, 306hz.

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Old 12-04-2015, 03:50 PM   #20
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https://www.miataturbo.net/megasquir...it-miss-84668/

Max decel load is wacky. You basically are going into closed loop as soon as you start decelerating, even if its quickly.

The rest of my settings are slightly off, because I've been battling this dying issue, and so i bumped the ramp to target times and stuff.
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