Any thoughts whats happening here?

[VL400]

Your IAC steps at idle are way too high and caused the problem. RPM hit 2k RPM and IAC did its step reset, but as it took nearly 200 steps out it stalled the engine.
Edit: noticed you don't have an iac. Will check the log again later but that sure lined up well!

Another tweak worth doing is changing "Accel Enrichment Param - AE delta throttle threshold " to 1.17%. It can help stop AE being triggered by tiny TPS movements, this may be happening to your steady state conditions.

[VL400]

Oh and the coolant temp voltage thing, there are two tables in the ECU (can see these in the XDF). One is 384 ohms and the other 3840 ohms. The ECU switches the pullup resistor to these values, 384 ohms hot temps and around 4000 ohms when cold.

Works the same as you explained just uses the different values. Its done like this to operate the very non-linear sensor in its most linear section over a wider operating temperature. Another one of this things the aftermarket ECUs do poorly with.

[Charlescrown]

OK well I changed the Accel enrichment param to 1.17% and put a fuel pressure gauge on the engine. After 6ming 48 seconds the same occurred. The fuel pressure did not budge so I know it's not fuel. I have attached the new log. What concerns me is the voltage change at 6.48 and 6.5 when the engine has stopped. When the engine cuts out the battery voltage drops from 13.7 down to 12.6 expected but then quickly rises up to 13.3 after 2 seconds. This little bit seems odd to me as if something is pulling current out of the battery during that time. I will try disconnecting all other electrical items and try again.

[Jayme]

whatever it is, I dont think its caused by anything the tune is doing. I reckon go back to basics. watch the spark with a timing light and when it cuts out, note if the spark cut out or if the spark keeps firing till the engine stops. do the same with a light bulb on the injectors. itll be one or the other.

[immortality]

The fuel pump generally continues to run for a couple of seconds after shut down until the oil pressure drops enough, that might be enough to explain the voltage drop.

[Holden202T]

yeah agree .. or thermo fans if they are on.

[VL400]

Yeah I agree after looking at the latest log, what Jayme suggested is where I would be starting.

Some other minor tweaks after you fix the stalling issue, as there is no IAC can clear these two items...
IAC - Idle spark Adjustment params - Idle spark correction limit = Set to 0
Idle Fuel Param - Lowspeed enrichment multiplier Maximum = Set to 0

[Charlescrown]

Well thermo fans are not on when it occurs. The pump may be the voltage drop I see on the log it's for 2 to 3 seconds food for thought. The ignition yes I will try that put a timing light on and see what happens. I don't think it's the pulse generator in the dissy because the rpm on the log tapers down as the engine dies and I assume that's the signal used to display rpm data.
Will turn off those settings too. Back to the testing.

[vs ss]

Years ago I had an 808 that used to cut the engine at the same temp just about every time. I cannot remember the exact temp but it would just cut out and start almost straight away again which was dangerous when I left work and had to pull onto a highway a couple mins down the road.
New pcm and all sorted.
Just throwing some ideas around as I did every test and overlooked the pcm at first.
Cheers.

[Holden202T]

yeah i've had similar sorts of things, one ecm would just randomly on key on corrupt my nvram, was very random, ended up putting another ecm in it and haven't had an issue since ....

not surprising though given the age these things are now.