QuestionQUESTION: I saw you answered a charging problem for another gentleman. "Question is, despite the change over, it would appear the alternator is not charging the battery as expected. I had the charging system tested and the alternator is functioning (Car battery died, was jumped, alternator got me home, but failed to start once home due to dead battery). I also replaced the regulator on the fire wall assuming that could be the problem as well. However, despite my best attempts, the battery will not stay charged even though the battery test good at local auto parts store. Your help in remedying this problem would be greatly appreciated." My situation is similar, good battery, good alternator, but mine is a rebuilt replacement. At the same time I had and HEI ignition installed connected to the black wire from the old ignition coil, the white wire was left unconnected, also the same guy put in a mini starter, a two wire type connected with the larger gauge wire of the three and he left the other wire hanging. The starter has power to the ignition pole only when cranking, the other hanging wire seems to have no power to it. Colors are supposed to be yellow and purple, but they have faded so i can only tell you the gauge of wire.
Please help me get my car back on the road, thanks..
ANSWER: Ok, lets start with one problem at a time. Do you have a digital voltmeter? If so, place it across the battery terminals with the engine running at a fast idle. The voltmeter should read between 13.2 volts and 14.3. If it does the alternator is charging, if it does not the alternator is not charging. Let me know the results and then we will go from there.
Brad
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QUESTION: I have an analog meter which reads 12.5 volts on all locations under the hood of the vehicle. The alternator was checked on the machine at the auto store and it showed a reading of about 13.7. The gen light is on at low idle, off at high idle but no change in volts with either idle speed.
ANSWER: Is this a 4-4-2? Dos this car have a separate voltage regulator? 72 was kind of a cross over year. Some models ran the S-1 series with integral regulator, some ran a transistorized regulator, and some ran the magnetic coil regulator that can be identified by having a sheet metal cover held on with two screws. Let me know. It is clear that if the alternator tested ok in the parts store then the problem is the car or the regulator. There are more than one possibilities depending on the type of alternator system that you have.
Brad
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QUESTION: This has an external regulator with four wires going to it, with a steel case with two screws, it was a Cutlass Supreme 350 4bbl, now it has a 455 in it. Not a 442. The odd thing is everything was working fine until the engine was replaced. Thanks for you help on this.
AnswerNothing odd here. It is something that was done or not done in the installation of the new engine. So, lets see if we can sort it out and play Sherlock Holmes. Lets start with the voltage regulator. If you hold or look at the plug on the voltage regulator so that the wires are pointing down as the connector is attached to the mounted regulator the left wire is the field, the one that attaches to the field terminal of the alternator. The next one or number 2 runs to the R terminal on the alternator. Number three runs to the horn relay + side and carries live voltage all the time. It is not switched with the key, that is terminal number 4. It carries voltage to the regulator when the ignition is turned on and is dead when the key is off. To test this one jump number 4 wire with the connector disconnected from the regulator to ground and turn on the key. The gen light should come on and go off when the jumper is removed. Now if this works and you have voltage at terminal #3, make up a jumper wire to connect terminal #3 to the field terminal with the regulator disconnected. With the voltmeter connected across the battery start the engine and do not race it but let it idle. The voltmeter should run up in the 13 to 14 volt range. If it does the alternator is putting out and the wiring between the alternator is sound. Next check to be sure that the battery is grounded to the chassis, the body, and the engine. If there is not a good connection to all three the electrical system can do funny things. Check these items and let me know where you stand.
Brad
