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*HEI451* · 09-02-2012, 10:20 AM

Was it a rebuilt alternator? If so, what supplier? Some rebuilt's are no better than the old, broken part they were when they were replaced before the "rebuild". There are part stores that can load test the alternator off the vehicle,. and that should be done, but, not just a quick 20 seconds and say its OK, let the alternator run until it gets to operating temp, then, load test it.

As far as a regulator, it appears you have a remote regulator, or you wouldn't have mentioned it separately. There are two different kinds. One is a manualk type, uses points and electro-magnets to operate, and was on the truck when it was built decades ago. They work, but, not as good as type 2. Type 2 is a fully electronic regulator, no points, and works leaps and bounds better than the type 1's do.

You should always try to use the type 2 electronic ones. If you have ever seen the headlights oscillate from dim to bright to dim to bright, this is the type 1 regulator turning the alternator on and off, on and off to charge. Type 2 engages the alternator for charge, holds it that way, and drops excessive voltage to chassis ground, no oscillation, more consistent charging. Alternator electric "wear" is mostly eliminated with the electronic regulators.

The alternator itself can have a weak winding in one of the three, two bad ones, diodes out, many different things. It is interesting that you actually got 15 volts out of the system, something was working correctly on the charging when it did that, but, doesn't sound like it stayed that way.

I would have to suggest getting the alternator tested, again if it was before, even though it is a "new to the vehicle" part. I would also think that IF the regulator was the old points type, it is defective, and that do3es happen in new ones of the type 1, and/or not adjusted correctly. Old types can be adjusted, but it isn't worth the low price of the type 2, and the hassle of adjustment.

As far as grounds, yes, regulator tho chassis, and, make sure the chassis to engine grounds are in place, clean and tight. Basically, both the alternator, and regulator want to be grounded straight back to the battery. This is done by the alternator being mounted to the engine, and the regulator to the chassis, chassis to the engine, then engine to the negative battery cable.

BTW, disconnecting the battery while the engine is running, is just not advised, especially if there is an electronic ignition in the vehicle.

09-02-2012, 10:20 AM	#5
HEI451 Account Suspended Join Date: Mar 2011 Location: Yerington, Nevada Posts: 864	Re: Voltage Regulator Question Was it a rebuilt alternator? If so, what supplier? Some rebuilt's are no better than the old, broken part they were when they were replaced before the "rebuild". There are part stores that can load test the alternator off the vehicle,. and that should be done, but, not just a quick 20 seconds and say its OK, let the alternator run until it gets to operating temp, then, load test it. As far as a regulator, it appears you have a remote regulator, or you wouldn't have mentioned it separately. There are two different kinds. One is a manualk type, uses points and electro-magnets to operate, and was on the truck when it was built decades ago. They work, but, not as good as type 2. Type 2 is a fully electronic regulator, no points, and works leaps and bounds better than the type 1's do. You should always try to use the type 2 electronic ones. If you have ever seen the headlights oscillate from dim to bright to dim to bright, this is the type 1 regulator turning the alternator on and off, on and off to charge. Type 2 engages the alternator for charge, holds it that way, and drops excessive voltage to chassis ground, no oscillation, more consistent charging. Alternator electric "wear" is mostly eliminated with the electronic regulators. The alternator itself can have a weak winding in one of the three, two bad ones, diodes out, many different things. It is interesting that you actually got 15 volts out of the system, something was working correctly on the charging when it did that, but, doesn't sound like it stayed that way. I would have to suggest getting the alternator tested, again if it was before, even though it is a "new to the vehicle" part. I would also think that IF the regulator was the old points type, it is defective, and that do3es happen in new ones of the type 1, and/or not adjusted correctly. Old types can be adjusted, but it isn't worth the low price of the type 2, and the hassle of adjustment. As far as grounds, yes, regulator tho chassis, and, make sure the chassis to engine grounds are in place, clean and tight. Basically, both the alternator, and regulator want to be grounded straight back to the battery. This is done by the alternator being mounted to the engine, and the regulator to the chassis, chassis to the engine, then engine to the negative battery cable. BTW, disconnecting the battery while the engine is running, is just not advised, especially if there is an electronic ignition in the vehicle.