Bung.
And a little bashing.
Turned out to be not quite enough bashing, but it's an improvement.
Bosch LSU4.9 sensor; with plenty of anti-scuffing paste on the threads, because I've had quite enough of sensors seizing into bungs this last couple of years, thank-you-very-much. (NOx sensors are M20x1.5, in case you ever needed to order a tap.)
Anyway, that sensor is controlled by an adorably small little box from LD Performance.
It almost looks like it fits in there!
But it doesn't, quite.
I'll keep trying, because it'd be just too damn convenient if it did. I already shaved the sides of the 3D printed end-caps down to make it fit that much, I might be able to get the front and back shaved down enough to close the lid.
Things the LD Performance wideband controller has going for it:
- Compactness!
- Doesn't need a gauge-pod stuffed away somewhere
- Has an OEM-style warmup routine, rather than just smacking the sensor with full heating every time (Should help sensor lifespan)
- Doesn't need a daft "free air calibration" dance
Forgot to bring my laptop down with me today, though, so didn't try it out yet. Still waiting on the starter heat blanket thing, too... (Apparently it's shipping from China, rather than the UK. Ah well.)
The Next Day
Remembered me laptop today! Got to try it out, and it works quite nicely. And today's session has brought up two key things...
Firstly, my coolant and air temp sensor calibration isn't quite right. They were both reading within a degree of eachother, but at -23°C. Now I know it's been sub-zero overnight, here, but it's not been that far below zero!
Thankfully(?) the cold weather will continue, so I should just have to grab my multimeter from wherever I've hidden it, and adjust the calibration table to bring it more in line with reality at the colder end. I have other thermometers in the shed, and they were all showing the air temp to be in the region of 3°C at the time; I'd not be surprised for the block and coolant to be colder, holding the chill from the previous night.
Secondly, why the truck stumbles and hiccups at idle!
..yeah, that'd do it. 
With the choke on (and corresponding throttle opening)
during warm-up, it's 12~13 to 1, which is more in line with what I'd
expect; so I shall have to do some idle mixture tweaking. I've heard
of lean-burn, but that's bordering on ridiculous... 