Few things. IAC opening on decel, accel enrichments - Miata Turbo Forum - Boost cars, acquire cats.

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Old 07-02-2016, 07:21 PM   #1
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Default Few things. IAC opening on decel, accel enrichments

IAC valve opening on decel, this is because of the shift settings right? Leave valve open for "x" seconds. ?
I also noticed my Injector PW would pop up on decel, but I have DFCO enabled. Any cause for this?
Accel Enrichment. I searched, I read, I tried. I plotted my 4 points for positive at 22.0 for low, 150 for medium, 275 for fast, and 650 for stabbing, after reviewing my tpsdot on megalog viewer for a few logs. The highest tpsdot I got was around 601%/s, so I added a little room (now I see I have got 916%/s). Problem is, the fast and stabbing seems smooth, but medium and low are horrible. Also coming off of decel any kind of throttle is causing a huge kickback, almost like hitting a spark cut.
Also, this is a little weird to me, but can a thermostat opening cause temps to go from 187 to 155 in less than a second?

Attached are a few screen grabs, as well as my current tune and marked log of problem areas. Any and all help is very much appreciated.

Coolant temp dropping



IAC valve

Attached Thumbnails
Few things. IAC opening on decel, accel enrichments-80-coolantdrop_2867243533fbaa1e4dafbc23229ab232f46d5f49.jpg   Few things. IAC opening on decel, accel enrichments-80-wgat_adff87ed5781e3ce4697c609ba75b7ef17d7c607.jpg  
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File Type: msq main.msq (203.7 KB, 23 views)
File Type: msl 2016-07-02_16-45-23_modified.msl (4.99 MB, 30 views)
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Old 07-02-2016, 07:26 PM   #2
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Sorry, I put this in the wrong section. Can it get moved to megasquirt please?
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Old 07-02-2016, 09:29 PM   #3
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IAC opening when you lift is dashpot of initial/last values taking over.



You aren't spark cutting on partial throttle, you are probably under minimum injector opening time. You'll et reversion off partial squirts and it will buck like crazy. Needs more fuel there.
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Old 07-02-2016, 09:50 PM   #4
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So I need to add more fuel for accel enrich on my low and medium plots?

It's set up like so:
-878 - (20.8)
-240.4 - (3.8)
-91.5 - (0)
0 - 0
22 - 17.5
150 - 30
275 - 40
650 - 55
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Old 07-03-2016, 12:15 AM   #5
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No, add fuel using the VE table. Accel adds fuel to the base VE value. You are trying to bandaid steady state fuel problems with temporary enrichments.

If you can't come off overrun smoothly with no accel enrich triggering you're too lean.
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Old 07-03-2016, 10:00 AM   #6
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looks like it is in fact prematurely opening; it's going to your exact initial value + dash-pot adder each time.

every time it's happening it's when you go from 17kPa vacuum to ~20kPa, but your map is set to 29.5kPa, so unsure.
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Old 07-03-2016, 10:23 AM   #7
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deezums, yeah the bottom row in my fueling ve was set at 20 kpa and had really really low numbers, I increased them to be closer to my next row, and about half a point less. I ended up increasing them by about 25 points. going to the store to get food in a bit so will report back.

brain, any theories I might be able to try?
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Old 07-03-2016, 11:38 AM   #8
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Much smoother throttle response, downshifting is a lot easier, and easier to get the car going from a stop now. Adding that extra fueling helped a ton, now I just have to refine it.

I went into closed loop idle control and set the 'shift settings' leave valve closed above 1400 rpm for 3 seconds. I changed it to 4 seconds, and the log shows the IAC shut for 4 seconds now, whereas before it was 3 seconds. So for some reason on lift and decel it thinks I'm shifting, what could cause this? I've also noticed around 2100 rpm in gear on decel the car lurches forward because the IAC is opened up. Thanks for the help so far!
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Old 07-03-2016, 12:57 PM   #9
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I do things a little different, I have dashpot pretty much entirely nerfed and I never close the idle valve. I use an initial value table that's MAT driven, since the valve never closes and you've got a table it's always going to be targeting your idle RPM, not something like 2K rpm. The valve will mirror the initial value table until you actually enter closed loop idle, so if you set the RPMs a few hundred higher on the table it acts as it's own dashpot.

The only real problem is I really need dashpot for low RPM throttle blips, to keep from running through 700 rpm before going back to 900, so I just added my stock 1.6 dashpot back.
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