By pass Volt reg install old style?

Tiny
HUEY777
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Kills truck makes it die
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Friday, March 23rd, 2012 AT 5:32 PM
Tiny
CARADIODOC
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Did you have the battery disconnected when you took the wires off the alternator? If you did, the Engine Computer "lost its mind" and has to have "minimum throttle" relearned before it will know when it must be in control of idle speed. To meet the conditions for the relearn to take place, (start with a charged up battery), drive it at highway speed with the engine warmed up, then coast for at least seven seconds without touching the pedals. You'll likely have to keep one foot on the gas pedal to keep it running until that relearn takes place. That seven-second coast is similar to coasting off an exit ramp, but you can do it anywhere on any highway.

A working alternator will load the engine down quite a bit and that's probably why the engine stalled. The only two things left then are the voltage regulator is dead or that terminal for the green wire in the plug is stretched or corroded. A defective regulator is the more likely of the two. By grounding that green wire at the plug, with that one test you just proved the wiring is okay for the entire rest of the circuit and the alternator is okay too. If you want to be 100 percent sure the system works, do that test again after relearning minimum throttle so the engine will stay running. Then you can see what the proper full-field test does when you ground that wire. This is a standard, very quick test done to determine whether a charging problem is the fault of the regulator or something else. I explain the procedure for Fords, GMs, and Chryslers on my web site.

The first step is to mount the new voltage regulator to the body, near the computer. The housing has to make good contact to ground it so it can't be insulated by paint or rust. If you get the regulator from a salvage yard, get the plug too with a bunch of wire. You'll see the plug has a blue and green wire. Those go to the two small terminals on the back of the alternator. Probably the best idea, to keep from butchering the original wiring, is to simply leave the black plastic block and terminals off completely for now. Leave the fat output wire bolted on. For the time being, just run the two wires from the regulator to the two small studs on the alternator. The system won't work yet because we need to connect the blue wire from the truck's harness for the power source, but I think there's an easy way to do that which doesn't involve running more wires.

To figure out which wire that is, measure the voltages on the two wires shown with arrows. First do that with the ignition switch in the "run" position but the engine off. If both terminals have 0 volts, measure them again with the engine running. One will have full battery voltage and the other one should have 0 volts. Tell me which one, by arrow color, has the voltage. Also tell me if you had to have the engine running or not to get that voltage.
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Friday, March 23rd, 2012 AT 6:14 PM
Tiny
HUEY777
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Red arrow which on the alt is lower of the two small wires
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Friday, March 23rd, 2012 AT 9:28 PM
Tiny
HUEY777
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Also ran and got a new vr1 reg and had search the junkyard for harness have reg mounted on fender well now
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Friday, March 23rd, 2012 AT 9:32 PM
Tiny
CARADIODOC
  • EXPERT
There's a green and blue wire in the plug for the regulator. Those two wires go to the two small terminals on the alternator. Either wire can go to either terminal, BUT, ... For convenience, to power the system, see if you can bolt on only the one terminal in the plastic block that has the red arrow. That terminal must go to whichever stud you hook the blue wire to.

Did you have to run the engine to have 12 volts on that terminal?
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Friday, March 23rd, 2012 AT 9:50 PM
Tiny
HUEY777
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Just trun on ignition switch on
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Friday, March 23rd, 2012 AT 10:41 PM
Tiny
HUEY777
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Hooked up just like you told me to but I had cut the little conecter on the green side of existing harness but now my truck is up and running everthing works and it charges thank you very much
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Friday, March 23rd, 2012 AT 11:51 PM
Tiny
CARADIODOC
  • EXPERT
What do you have for battery voltage with the engine running? It should be between 13.75 and 14.75 volts. It might be a little low but slowly rising if the battery is run down.

Any splices you might have made in the wires should be soldered, then sealed with heat-shrink tubing. Electrical tape will let moisture in, and it will unravel from the heat under the hood. They make that tubing now with hot-melt glue inside to really seal out the moisture.
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Saturday, March 24th, 2012 AT 12:28 AM

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