After getting the fuel system taken care of, there was still a matter of dealing with the missing fuel selector switch. Well, it wasn't missing, just removed. The original plan was to install a jumper that would route the switched 12v power to the line feeding the fuel pump. This concept was fine on paper but when implemented was not too well thought out. After removing the dash/gauge panel, I installed a jumper and tried to get the pump to cycle on. It took me a while to figure out why the pump wasn't coming on. First problem was the idea I had the key on the whole time. This was partly because of the crazy chimes the truck was making when the key was initially turned on, especially when I tried to simulate a start to see if the starter would crank. So, the key was left on. Midways through this I also realized that there was a matter of the fuel gauge as well as the pump. This made me realize that I would have to reinstall the selector switch. At the same time, I took a moment to install a jumper from the fuse box, coming from a switched 12v circuit that was no longer used on the truck to confirm that the pump would come on. Knowing that the pump would come on I plugged up the selector switch. Once the selector switch was plugged back up, I then discovered what was going on. First, the selector switch had to be sending some kind of feedback to the ECU through one or both circuits (pump or gauge) in the fuel system. All the crazy chimes shut off at that point. Second, when I turned the key on, I heard the fuel pump cycle on for a couple seconds. I then realized that what was happening on the power lines for the fuel pump was the idea that when the key is turned on, the ECU cycles the fuel pump for a couple seconds to prime the EFI system prior to starting. Once the truck is cranked the pump will continue to cycle on until the system starts then the ECU will command the pump to stay on. Because this is a low-pressure system, the fuel pump needs to stay on all the time, even during startup. I had to keep the jumper in place that I used for testing the fuel pump and tap into the power line feeding the fuel pump so when the key comes on it will cycle the pump on all the time regardless of the ECU. With that, I had to keep the fuel selector switch. It's just as well anyway, because the switch in place at least looks better and original than the hole that would've been present otherwise. Now if there was any chance that I could've made the pump hold prime in the system, even with this low pressure setup, having the fuel selector switch would've served like a security measure as it would've kept the pump from coming on when switched in the other position. I might be able to put the 12v jumper on the input side of the switch. I'll have to look at that again... The next thing that I had to address was the starter and why it wasn't cycling on. Even after shutting up the chimes, the thing still wouldn't send power to the starter solenoid to crank the starter. I had to go through a step by step process of tapping into the circuit feeding the starter solenoid, ohming out the sections of the circuit to see where I might be losing continuity. After moving in and out of the cab, tracing the circuit from the ignition switch to the junction plug and across the junction plug, I finally found that I was getting a way higher than normal resistance reading at the plug where all the wires went through the firewall. Even after reseating the plug, I still had that odd ass resistance reading. I ended up installing a bypass circuit, basically a wire that bypassed the old circuit, going through the firewall, passing the junction and tapping into the circuit after the engine bay fuse box. In order to not complicate things more than they already were with the bypassing and all the other fuckery that was being done in this truck and this newer system, I bypassed the fuse box. Even though I tried tapping before the fuse box, because there is probably a secondary circuit with another smaller relay cycling on the starter solenoid, I just bypassed everything that wasn't really needed. Besides, if I dig into the engine bay fuse box, I might cause one of the other circuits still being used to not act right. It's best not to overcomplicate things in this uncharted territory. After doing this little bit of tomfoolery under the hood I was able to hit the key and make the starter pop as intended. With the couple of minor electrical issues addressed, I can now move back into the engine bay for our final batch of work, which is installing heater hoses, a smog pump so I can put the stock serpentine belt back on, and the distributor and wires. I also still have to bleed the clutch master cylinder. Once that's all done, other than adding fluids and fuel, I should be ready to crank this pile over for the first time.
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