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Old 05-06-2013, 10:42 PM   #1
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Default Weird idle issue- MS1V3

I'm having a weird idle issue. I start up the car, and it idles pretty well at ~850 RPM. AFR's are at about 14.7-14.9, vacuum is good, timing is at 17* and CLT is at 200*F.

After about three minutes or so of idling, the car will rev to about 2000 RPM and then go back to 850 over and over again. It will do this endlessly. CLT is still the same as before.

Any ideas? Car is a Greddy'ed 1.6 with stock injectors, though I have the waste gate arm disconnected at the moment.

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Weird idle issue- MS1V3-datalog.png  
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File Type: msq CurrentTune.msq (39.9 KB, 44 views)

Last edited by albertogti117; 05-13-2013 at 01:46 PM. Reason: Attached datalog and MSQ
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Old 05-07-2013, 10:48 AM   #2
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Can you post a data log of the issue and a copy of your MSQ? There are a number of things that can cause this.
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Old 05-07-2013, 10:49 AM   #3
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Sure. I'll try and do that this afternoon.
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Old 05-13-2013, 01:48 PM   #4
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Matt, I have attached a datalog and a copy of my MSQ. Still kind of new to this so let me know if you need me to do something differently when datalogging.
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Old 05-14-2013, 12:25 PM   #5
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check your idle dc over that period you logged - i bet it is cycling up and down to make this happen. i had the same on mine and it didn't make any sense. it was a while ago now but i think i fixed it (or at least managed a work-around) switching over to warm-up only, and back to closed loop again. for some reason my MS just got itself in a mess.

of course, you do need to check your closed loop idle settings are sensible
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Old 05-14-2013, 01:28 PM   #6
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Idle settings are as follows:



I believe I got them from the DIYPNP 90-93 basemap.
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Old 05-14-2013, 02:10 PM   #7
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Skinny, I did as you said and logged the idle DC when the event happens. It pings to a value of 63 and then goes back down to 18. When switched to warmup only, the the issue doesn't happen so it's definitely a problem with my closed-loop settings. Here's a log:

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Old 05-14-2013, 02:16 PM   #8
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where's the AFR in the above log...

you also need to ground your TPS input; that's not helping anything.
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Old 05-14-2013, 02:25 PM   #9
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My factory TPS is unplugged currently. Is that incorrect? I read that you're supposed to unplug it because the 1.6's don't have a linear TPS.
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Old 05-14-2013, 02:27 PM   #10
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well look at the value it's giving in your logs, the input still floats around and goes crazy. Could have an effect, consdiering you have a TPS ADC threshold of 85 and your TPS is reporting 19500ADC in that log...


but im much more curious about seeing the AFRs.
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Old 05-14-2013, 02:40 PM   #11
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Megalog viewer only lets me select O2 as a view (which I assume is in volts). How do I change it to AFR?
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Old 05-14-2013, 02:59 PM   #12
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If the unit is wired for VTPS, would my current configuration (Having stock 1.6 TPS unplugged) be that cause of whacky TPS ADC?
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