On the way home from the most recent 24 Hours of LeMons at CMP (where my turbo voyager received more compliments than our race car *grin*), we had one of the worst rain storms of the year. The vehicle started acting like it was running on 2 cylinders. Couldn't figure out what the problem was, so we replaced 2 loose spark plug wires.
Next day on the way to work I went through a puddle and blew a fuse (on the circuit that goes to the shutdown relay). When I purchased the car, it had been blowing this fuse, but the problem turned out to be a short in the wire that goes to the fuel pump. That was fixed already, so I figured it must be some other part of the circuit with a more intermittent problem.
That was the start of my problems. Since then:
* the battery went dead and when I replaced it I discovered the alternator was not charging
* replaced the alternator with a higher amp ND
* still can't get a charge - time to pull out the multimeter
* varying potential across battery terminals (11.5 - 13.5V, depending on whether the battery is charged and whether I'm revving the engine)
* 12V at the one field terminal (to ground) and 9-10V from the other to ground. about 1.5-2.5V across the terminals (but not exactly the 1.8 that I've read can happen with a bad voltage sense wire).
* full field produces 18-20V from the alternator
* tried to install an external regulator but no luck getting it to work
* next time I drove the car instead of undercharging it was producing 13.5-14V - YAY! But then when I got on the interstate it started climbing up, a little bit at a time, to 18+V, until I turned on the headlights to bring it down to 16V
* next time I cranked the car up it was undercharging again.
* checked the voltage sense wire. the connection to my splice was loose, so I redid the splice. cranked the car up and it was overcharging again, but it didn't last long before it was undercharging again on a subsequent crank. btw the voltage sense wire is labeled incorrectly in the 1989 service manual (both the color and the name) -- took me a while to figure this out.
* time to redo all the wires from the beginning. removed all the friction tape and retaped all wires that hadn't been messed with. all the other wires (which have been re-spliced) will be taped separately. replaced all the fusible links with links from a junkyard v6 (not exactly the right gauge but it will do for now).
* removed the computer to check the power module. nothing obvious until I cleaned off all the grime:
Could this be my problem? (looking at the brown capacitor whose rubber coat has worn off)
Questions:
* If this is the problem, maybe I still have a chance of getting the external regulator to work?
* If this isn't the problem, what does this capacitor do? Do I need to replace my power module? if I need to replace the power module, where do I get one?
* What is the extra connector (one red and one black wire) on the v6 power module (connects to the LM)?
* Why are the wires from the battery to the fusible links and from the fusible links to the starter relay red on the '89 V6 and black on the turbo? AFAICT from the service manual both should be black on both cars.
* What is the proper way to ground an external voltage regulator? One of the regulators I purchased was painted and the paint doesn't conduct electricity. There is an exposed metal connector on the front but I'm not sure how to connect a ground wire to it.