On my motorhome. 1990 VIN Econoline 350 460 FI gas. No idiot light-- just an ammeter.
Came with a dud alternator or wiring. Discovered via research that its "2G" alternator was horrible trash, trying to output all its power through two 1/4" spade lugs. Elected to fix it with a used 130 amp "3G" alt out of a 1994 Mustang V6. Bolted right up. Added a 6-8 gauge starter cable left over from my motorcycle and 100 amp breaker to wire it to my battery (+) terminal, and used the truck's 3-pin (plus stator) connection. No worky. Tested the A/S/I connections, everything had voltage where it should have per the schematic.
Alternator tested bad at autozone, FWIW.
Blessed with an extra pigtail from the donor vehicle, I made my own "idiot light" between Battery (+) and the field ( I ) connections, but still couldn't get this to work. Aggravated, I got a self-exciting regulator, installed it, and it worked. Sometimes it took more than a "blip" of the throttle to get going but it always worked, until two weeks ago. Made a eight mile trip to get inspected at my mechanic on battery power alone, then two miles into my return home the alt came to life.
Not really one to know what's going on in that little transistorized box, I found a tapped hole on the back of the alternator case and added an extra ground wire that went straight to the battery (-) terminal. It worked perfectly... for two days. Always engaged with just a little throttle blip. Then it went back to its old self. The mounting brackets & fasteners aren't rusty, FWIW.
There's a screw for testing on the regulator, so I added a wire and ring terminal. Grounding the wire full-fields the alt. Doing this, even for a second, also "tickles" the not-self-starting self-starting regulator and gets it going for the duration of the engine run.
So here we are, options:
The factory wiring, for whatever reason, hates life. I could rig a new wire from ignition (+) through a 500 ohm (?) resistor to the "I" Terminal on the A-S-I block of a "normal" regulator. Pros: It's normal, and if I need an alternator or regulator in the future I can get one at any junky parts store. Con: I've devoted a lot of diagnostic time in this direction without positive outcome.
I could add a temporary push button to the ground-test wire to energize the field, but it looks ghetto and might impact resale value. Con: If one forgets to do this they could drive off to a flat battery.
I could get some sort of cheapo timer module that grounds the test wire 5 seconds after starting for 1/2 second. Con: Things are really getting into the Rube Goldberg/ MacGyver weeds. And if the battery's healthy it could lead to an overvoltage situation.
I could get a mopar (!) external regulator and wire it up to the ground-to-test wire like the alt is completely unregulated. Con: Two regulators would be fighting each other, might let the smoke out of something.
Gimme some feedback!
Came with a dud alternator or wiring. Discovered via research that its "2G" alternator was horrible trash, trying to output all its power through two 1/4" spade lugs. Elected to fix it with a used 130 amp "3G" alt out of a 1994 Mustang V6. Bolted right up. Added a 6-8 gauge starter cable left over from my motorcycle and 100 amp breaker to wire it to my battery (+) terminal, and used the truck's 3-pin (plus stator) connection. No worky. Tested the A/S/I connections, everything had voltage where it should have per the schematic.
Alternator tested bad at autozone, FWIW.
Blessed with an extra pigtail from the donor vehicle, I made my own "idiot light" between Battery (+) and the field ( I ) connections, but still couldn't get this to work. Aggravated, I got a self-exciting regulator, installed it, and it worked. Sometimes it took more than a "blip" of the throttle to get going but it always worked, until two weeks ago. Made a eight mile trip to get inspected at my mechanic on battery power alone, then two miles into my return home the alt came to life.
Not really one to know what's going on in that little transistorized box, I found a tapped hole on the back of the alternator case and added an extra ground wire that went straight to the battery (-) terminal. It worked perfectly... for two days. Always engaged with just a little throttle blip. Then it went back to its old self. The mounting brackets & fasteners aren't rusty, FWIW.
There's a screw for testing on the regulator, so I added a wire and ring terminal. Grounding the wire full-fields the alt. Doing this, even for a second, also "tickles" the not-self-starting self-starting regulator and gets it going for the duration of the engine run.
So here we are, options:
The factory wiring, for whatever reason, hates life. I could rig a new wire from ignition (+) through a 500 ohm (?) resistor to the "I" Terminal on the A-S-I block of a "normal" regulator. Pros: It's normal, and if I need an alternator or regulator in the future I can get one at any junky parts store. Con: I've devoted a lot of diagnostic time in this direction without positive outcome.
I could add a temporary push button to the ground-test wire to energize the field, but it looks ghetto and might impact resale value. Con: If one forgets to do this they could drive off to a flat battery.
I could get some sort of cheapo timer module that grounds the test wire 5 seconds after starting for 1/2 second. Con: Things are really getting into the Rube Goldberg/ MacGyver weeds. And if the battery's healthy it could lead to an overvoltage situation.
I could get a mopar (!) external regulator and wire it up to the ground-to-test wire like the alt is completely unregulated. Con: Two regulators would be fighting each other, might let the smoke out of something.
Gimme some feedback!
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