Engine Stalls on Rapid Deceleration
 

Hi all, sorry for the second post in quick succession. I'm jumping right into tuning but I'm having an issue I can't figure out how to resolve.

I'm running an MSPro3 PNP on my NB Miata (2004). Apart from a wideband O2 sensor (CANBus) and the ECU, it is stock. I verified the ignition timing.

When I rapidly decelerate, I stall. I have no issues with slow deceleration.


Log #1
At about 400 seconds in I accelerate from idle. At about 450 seconds it stalls. The AFRs go to about 16 just prior to stalling.

Log #2
At about 330 seconds in I'm decelerating from about 2800 rpm. It looks like the spark advance drops off dramatically, which leads to a rise in AFR into the 16s/17s and then a stall.

Thanks for any help you can provide!

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Log #1 screenshot
https://cimg8.ibsrv.net/gimg/www.mia...103a14b1f3.png


Log #2 Screenshot
https://cimg1.ibsrv.net/gimg/www.mia...85b0edc755.png

In case someone else encounters this, the issue appears to be a slightly kinked MAP vacuum line. I wonder if my brake or clutch pedal was kinking the lines, causing abnormal ignition timing and a stall.