Heating the fuel injection control unit for proof of its function is a novel approach. Maybe that's an automotive diagnostic approach. On Bricks, usually heat is applied to the Hall Effect sensor. A faulty sensor often temporarily fails after an engine is fully warmed up and has been run for a while; furthermore, a heat gun—not a hair dryer—seems more effective at creating sufficient heat to generate a problem with a faulty one. Bricks come with some unique attributes and treatment strategies. Your attempting to reproduce the failure is a commendable strategy often neglected by others; nevertheless, it's story time.
I bought my Brick in Maine. The responsible adult who owned it enjoyed riding it regularly and stored it in a well-built, dry barn but he wanted a Ducati so there we were. He allowed me to take an unattended 20 minute ride on the roads around Boothbay. I bought it on the spot and trailered it back to Vermont that day. When I backed it off the trailer at home, I started the engine and moved it to its permanent parking spot.
The next day I started it and headed down the mountain on the three-mile dirt road that leads to the river and civilization four miles away. I turned left after the stop sign at the river, the bike stalled and I coasted to a stop on the road's shoulder. Zip, zero, nada. No start, no lights, nothing. I knew little about the inner layout of the Brick so I did what any red-blooded bike rider would do; I called my partner of thirty years and pleaded with her to stop whatever she might be doing and bring me the Rider's Handbook that came with the bike. She had mercy on me and delivered it along with a benediction and a piece of apple crumb cake, then she got the hell back home before the cursing and self-recriminations started.
I looked at the fuse layout diagram in the handbook then pulled each fuse. All fuses, their blades and socket receivers were clean and intact. Then I came across the drawing of the LE Jetronic fuel injection control unit in its box mounted under the seat. I deduced which direction to push the latch of the unit's plug down in the hole of the box and figured out it disconnected by swiveling it from the right, but
first I noticed that the plug was not quite square into its housing. I pulled on right-hand the plug and it wasn't latched. I pushed it inward until it was latched and couldn't be swiveled outward, stood up, turned the key to On, pushed the starter button and she fired right up.
I didn't have another power problem until it stalled 60,000 miles later. That problem was caused by a dirty ignition switch and was intermittent. By that time, I'd read quite a bit about Bricks and their owners' frolics with them so I was ready. I was able to wiggle the key until it started, then rode it home. Cleaning it was the cure.
On a Brick being recommissioned, cleaning all electrical connectors, inspecting, cleaning and tightening all battery positive and ground connections, cleaning and tightening starter mounting bolts and connectors, and cleaning and tightening the main ground connection on the frame backbone should be happening early in the program. This problem is likely to be an electrical connection/oxidation problem. Intermittent fuel starvation from dirty injectors could be in the picture, too, but, as you know, electronics tend to run the whole show. Intermittent operation failures are tough but neglected Bricks can respond well to thorough tending to electronics cleaning, including the relays in the relay box beneath the tank.
With the given depth of your automotive mechanics experience, the reason for this condition is likely to be accompanied by an "Oh, there's the problem right there" solution at any moment.
