Re: Alternator wiring instalation

Posted by Don Shields On 2014/7/13 0:58:32

A prior owner had my car converted to 12 volt negative ground and installed an alternator. This alternator has two wires coming from it and unfortunately they disappear into a wiring loom. I suspect the heavier wire joins the battery cable at the starter motor and the lighter wire supplies the "Gen" light on the dash, but perhaps someone better versed in this could advise you more authoritatively than I can. I do know that the vast majority of alternators are regulated internally and do not use external voltage regulators. The regulator you describe is clearly for a generator and would be useless if you install an alternator.

Before taking that step I suggest that the electrical system should be checked. The battery might be on its way out and should be load tested. The system should be checked for drains or draws such as a trunk or glove box light staying on and draining the battery. With the condition present, the starter motor draw should be checked. If it's taking too may amps to function on a warm restart, an alternator will not correct the condition and the starter motor will still have to be rebuilt or replaced. Of course, the generator output and voltage regulator performance should also be checked. If either one is faulty, I'd recommend rebuilding/replacing them instead of installing an alternator. Your car's generator was designed to provide sufficient current to run the car as originally equipped. Only if I were going to install some high-draw accessory such as an electric radiator cooling fan or a modern resistance-type rear window defogger would I even consider replacing the generator with an alternator.

Another remote possibility for slow cranking on a warm restart is tight bearings in the engine. Has it just been rebuilt? If so, the condition should disappear as the engine breaks in.

I hope you can find the cause of the slow cranking quickly and easily. Good luck.