Fortunately I was able to pop the cover off the instrument panel and the needle for the temp gauge snapped back down when I pushed it. Temp gauge seems to work perfectly.
This is how I routed the 2002 harness into the engine compartment. Could have put this fuse block inside the car, but there's even less room there. Figure we'll mount it between the master cylinders.
Hole sawed through the firewall and down into the car. 2" holesaw is the biggest I have, getting the relay strip through there was a pain, but it's all in now.
Wire out of the instrument panel that goes to the alternator is black/white, so I spliced into that...
And crimped some spade connectors on that and the wire from the 2002 that goes to the middle alternator pin (red tape).
Alternator charges now. Works without the idiot light bulb installed too. Looked at the wiring diagram again and there is a diode that connects that circuit to one of the others so the alternator will still charge with the bulb removed or burned out.
My friend also was looking at the interior fuse block on the 2002 harness. There were really only three fuses we were still using. So we checked all that, unplugged that fuse block, and spliced three fuses into a few wires, and everything still seems to work. Except a few of the fan relays aren't working, but I think I see the fuse we missed that runs those, that should be a simple fix.
The accessories weren't working because I wasn't sure what the four wires to the ignition switch did after messing with it with the multimeter. My friend found the wire colors for those in the 99 FSM. I had spliced into the one that powers ignition, but there is a separate one that powers the accessories. So now the wipers and power mirrors work.
My friend rewired some 1000 ohm 10W resistors into the TCM with a terminal strip. A little nicer than the breadboard setup, they run much cooler than the 47 ohm resistors, and still no codes. Also pictured here is the tach adapter. They probably sell a million of these, they're super easy to set up and seem to work perfectly. Another thing I did was wire the fuel level wire that went to the 99 ECU to the 2002 ECU. No fuel level code since I did that.
Horn didn't work because we connected the plug for the cruise set/resume switch at the column to the 2002 harness. The horn goes through that plug. So that's an easy fix.
Looked at the VSS diagrams some more. The 99 goes straight from the trans to the ECU and speedo. The 2002 has two VSS inputs to the TCM and a torque converter speed signal (TCSS), which should still be working, I left it on the engine. Then it sends a VSS signal to the speedo, cruise control module (CCM), and ECU. The VSS signal for the ECU/speedo is a 0/5V pulse, the ones for the auto trans are AC, possibly sub 5V. So we spliced the VSS signal from the manual trans into the 2002 ECU/CCM and it seems happy.
The cruise wasn't working because I had the 2002 brake switch plugged into the harness, but without the pedal pushing against it, that made the cruise module think the brake pedal was pushed down. So I jumped that for now and the cruise works. We were getting a code for cruise control set, I think I fixed that by cutting a wire from the TCM to the CCM.
Actually drove it a few times with no codes, no check engine light, cruise works. It did stall a few times.
Then the check engine light started flashing. Misfire on cylinder 1. Seems like pulling that fuel injector plug doesn't change the idle at all. If you unplug any of the others, the idle drops, plug them back in, idle picks back up. So it seemed to be running on five cylinders, which would explain the unimpressive power.
Couple things semi related to that.
This thing pumps out a decent amount of smoke from the breathers when you disconnect the valve cover hoses. I should try it sometime on the white 02.
The black stamped steel covers for the fuel rails are heavy. They're probably 14 gauge steel and part of it is doubled up. Is that so when you're in a horrible wreck the fuel rails don't get damaged?
Speaking of super heavy, the passenger airbag is like a solid brick of steel. I'm very tempted to take the cover off and put it on the car and leave the airbag out. I'm not going to hook them up regardless. Just not sure if it's worth risking death or serious injury to take ten pounds off the car.
We also watched the ignition timing at full throttle, the ECU only gives it about 20 degrees advance at full throttle. Test drove the white 02 wagon and that also only has about 20 degrees advance at full throttle. So I could see bumping that up with a tune would help considerably.
This morning I went back at it, trying to figure out if that injector or coil or spark plug was bad. So I pulled the coil off and jammed a spark plug in it. I could barely get the engine to start, and it was idling rough at maybe 600RPM. The spark plug was definitely sparking. Put that all back together and it still seems to idle rough and slow.
When I checked codes I had a MAP code and O2 heater code (I'd unplugged it to get at the #1 coil pack). Cleared those and it was back to idling smoothly at about 900RPM. #1 injector still seems to have no effect on idle speed, others do. Wondering if #1 could be getting enough fuel from the other five cylinders from the intake manifold (if that injector isn't working) to sort of run with the ignition hooked up. The injector is getting 12V with the ignition on. I will probably replace the injector and the spark plug if I can get at it. Any thoughts on that?