I didn't try to power the fuel pump directly. Not sure how to do that. I'm assuming that I have to remove the plug, identify the pos and neg pin on the pump and apply power to it?
Power input at the fuse and relay: i checked voltage on both ends of the fuse. I removed the relay, tested it on the bench and it clicks. In other words, I don't think that I checked if I'm getting power input. Will do.
Correct, now is persistent. Every time I check or do something to it, I try to start the engine. It's still doing the same thing: cranks, no start and backfiring very, very load.
I'm on my way to the mountains for a weekend camping trip. I'll be working on this late Sunday or Monday and report back as soon as I can.
Regarding powering the pump directly - If it was mine, I'd just connect a 12v jumper pack or other spare battery to the positive and negative leads on the pump to get it to run.
The part I still don't get is the backfiring. Backfiring in my experience is due to incorrect timing or lack of sufficient spark that's causing the fuel to ignite outside the combustion chamber. If you have at any recent point had the plug wires off the plugs or coils, I'd double and triple check them.