Canon UC1 wont power up even with new batteries or power from the wall

sounds like you have a failing ecu. the capacitors in the ecu are worn out. there has been a lot of problems with the ecu on mazda's over the years, only take one out put overload from the alternator and the ecu starts playing up. no codes come up as it don't code its self. having the battery off is like a reset.

Sell it as qoick as possible before it pennys you to death, Like all the other over price toys out there in the last 20 years,

The tiny wires to the lock ign cylinder must have broken. Replace lock cylinder.

make sure you have power on small wire to starter when you turn key to sart

How is your charging system? Sounds to me like it's not charging your battery, so it runs until the battery cannot support the ignition load.

Regardless of age, battery discharging first needs to be addressed and fixed - bad battery or something in car (like a light) may be staying on when car is shut off.
Fuel pressure is too low - should be around 50psi and may be caused by an intermittent fuel pump or regulator problem.
The cause of the other problems is usually with the IAC or MAF sensors or the EGR valve - fouling at the EGR, IAC and/or throttle body is to be expected for a car this old.

Time for a new battery. Most places will test your battery for free. Expect to pay about $100.00 for a new battery for your truck.

If you didnt let it set on wooden blocks or similar, tires are probably shot, even if inflated. 1st time the engine starts over, it will be on dry cylinders, without oil, and will scratch the cylinder walls. Pull the plugs, pour a tad of oil in the cylinder, and put back the old plugs. It wont be easy to start, due to fouling, so have a new set of plugs as standby, but the cylinder sleeve and piston rings will be protected before that first start.

i was in the same situation inheriting one myself that was sitting for 7 years and had the same problem i changed ann fluids and got it cranking and almost started but the ground wire was glowing red so i sanded down a spot and put in a new ground. it got it running but never stayed so all i did was put a new alternator and ran new fuel threw it and it runs like a million bucks.now the only thing is the brake lines or master cylinder.

fuel prassure switch leaking fuel in to cylender causing a hydrostatic lock