Fuel Cut at WOT, VVT Swap MS3
 

I have swapped a 2001 VVT engine into my 93 based on the method in the mega thread. I have it running well except for one problem. The car will cut fuel if I go above ~90% throttle. It doesn't seem to matter what RPM, gear, accel enrichment (including 0 enrichment) or anything else I can think of. It is not just going lean it is completely cutting fuel as evidence by 0 pulse width when it happens. I have attached my tune and log file. The picture is of an instance where it happened 4 times in a row with me trying to be gentle with the throttle.

1993 VVT swapped
2001 gutted intake manifold
2001 tps
2001 injectors
MSlabs ms3
LC2 wideband

https://image.ibb.co/bXWurn/Fuel_cut_out.png

CLT rev limiter is engaging. Above 90% TPS, it bypasses, but the bypass rev limit is set to 0.

Nice catch, an interesting way to cure a lead foot I suppose...

Wow sometimes I feel dumb. Thank You.

No need to feel dumb, that is definitely a weird one. Full fuel cuts are always an ECU-induced limiter, so I just ran through all of those, starting with overboost protection, then AFR protection, then the rev limits page. Noticed you had pretty aggressive CLT limits, but it wasn't RPM dependent. A second look and I noticed the TPS bypass. It's set that way to prevent you from hammering on the car when it's cold. I would leave it like that and back down the CLT protections so you can go WOT at or above 160*F.

The original application is to have non-bypass induce a CLT based rev limit, preventing high revs on cold oil. However, in an emergency, above 90% TPS, that is ignored and the Rev Limit set higher. That enables you to potentially sacrifice a bearing while saving the rest of the car from a collision.

My understanding is that boost when cold is not as big a problem as high RPM when cold.

Thoughts?

My mind was thinking that it has to be some ECU safety measure but I had forgot about the rev limiter/throttle bypass. I'm actually considering turning it off. This is an autocross only car so I shouldn't have an issue with not having it warmed up (this is also the reason I am conservative with my low temp limits). I guess 160F is considered the safe temp for rev limiter action. Ill probably keep it dialed back a little until 180F.

I think this is the general consensus for all engine situations, Warm or cold. Problems with boost/bearing generally stem from detonation. Piston acceleration loads from rotating generally trump loads from boost.

I would worry about turbo bearings at low oil temps but that may be unfounded as I am just surmising.