Hey guys,
MS3X running my VVT swapped NA - the car runs fantastic other than this one issue. When cold, throttle tip-in results in a long, severe lean spike resulting in a severe hesitation. Hard to back out of the garage without stalling when completely cold. As CLT increases, it progressively gets better, and tip-in at operating temperature is pretty perfect.

I really have no idea what's causing this issue. My steady-state warmup AFRs are right where I want them. I've tried cranking up the cold AE setting to the maximum of 255% (from default 120%) and that made little difference. The log shows that AE is triggering and adding fuel PW during these events. Can it really need that much more fuel during cold AE? Anyone have any ideas?

In this log I kept blipping the throttle as I drove to demonstrate the issue as the car warmed up. (log is in the zip file, it's too big)

 

Those AE settings look absurd.



^ Those are the settings for Brain's VVT base map. I would start there.

 

Wow, that's way more fuel than I was using. I thought I started with the DIYAutotune base map for AE, but I must've screwed something up somewhere, as it also peaks at about 75% adder at 400%/s.

Anyway, copied down those settings and it seemed to make quite a bit of an improvement, although I've still got some hesitation, and a shorter duration lean spike to 20.0 when 'cold' (80F ambient). I'll try to add some more fuel when it's cold again, and post back.

Curious about the use of some MAPdot blend, I remember the manual suggesting 100% TPSdot with a vTPS, so I had set mine up that way.