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Car stalls in the heat when coming to a stop

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Old Jun 6, 2009 | 02:30 PM
  #1  
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Default Car stalls in the heat when coming to a stop

My car seems to be stalling several times a day when coming to a stop. It's typically under hot circumstances so I'm thinking perhaps my IAT is getting heatsoaked? It's located on the intake throttle body and I'm not intercooled yet. Hot highways and slow speeds are especially deadly.

I found this thread in a search:

https://www.miataturbo.net/forum/t34473/

Is that what I want to be doing? It's not a big issue when it's once every couple of weeks but it's getting ridiculous now. AC doesn't even stand a chance!

I've attached my msq and a recent datalog of the problem. Albeit the datalog isn't as good as I had hoped because it wasn't as hot yesterday but I managed to provoke the problem once I turned the AC on.

Thanks.
Attached Files
File Type: xls
idletimebaby.xls (1.47 MB, 111 views)
File Type: msq
wallmart145.msq (35.3 KB, 151 views)
Old Jun 7, 2009 | 12:28 AM
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Did you adjust the coolant density settings...that helped me and I also wrapped my IAT sensor in aluminum foil to reflect radiant heat
Old Jun 7, 2009 | 01:39 AM
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Nope, that is still on "Normal Correction" as per the PNP base map. Did wrapping it really make a difference?
Old Jun 7, 2009 | 06:54 PM
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Anything obvious I'm missing out on here? Got a new job I'm starting tomorrow, really not looking forward to the car cutting out during rush hour in downtown Atlanta. :(
Old Jun 7, 2009 | 07:20 PM
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Have you taken scotty's advice and enabled coolant/iat air density correction? If your IAT sensor is getting heatsoaked, then that's what you need.
Old Jun 7, 2009 | 07:26 PM
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Nope, I'll enable it then. Are the settings already in there ok? I didn't want to enable it and have it running on anything that could potentially mess it up even more.

This post from that thread up top confuses me:

https://www.miataturbo.net/forum/t34473/#post401384

These attached settings good?
Attached Thumbnails Car stalls in the heat when coming to a stop-coolant.jpg  
Old Jun 7, 2009 | 07:37 PM
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No. Try something like this:

Temp/Offset
50/105
55/110
60/115
65/119
70/124
75/129
102/155


It can be improved upon, but that's what was in the MSPnP config.
Old Jun 7, 2009 | 09:18 PM
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The MSPNP config? Odd, this is a MSPnP for a 96. Reading up in the help section it talks about only doing this if your car is tuned, which makes me think, what's the actual problem with the "Normal Correction" setting?

Last edited by jdmaddox88; Jun 7, 2009 at 11:06 PM.
Old Jun 8, 2009 | 12:06 PM
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Try adding more advance at idle - change the advance at those two low RPM bins from 12 to 18 degrees and see if that helps.
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Old Jun 8, 2009 | 07:10 PM
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Cheers Matt, not quite sure why that got reduced. Will report back after findings!
Old Jun 8, 2009 | 11:17 PM
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Ok, I upped the timing there and then spent some time tuning the fuel for idle and it seems to be better. I didn't get to drive it properly after I got it tuned in as I noticed an unpleasant noise coming from my supercharger... bollocks
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