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Faulty alternator?

Hello! I have a 93 4cyl Camry and for a while now every time I turn the head lights on the car looses power, especially at idle when the idle speed goes down. Does this mean it's time for a new alternator? The battery is new and connections are fine. Thanks for your help.

Cheers, Erhan

Reply to
Erhan
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I had a service station carry a brand of battery that was failing after 6 months, he dropped the brand, a service station can load test your battery and alternator on the car, it could be just dirty or loose battery cables but who knows it could be more

Reply to
ransley

you can check the output of the alternator with a volt meter, if the alternator is working it should read 14.5 volts or a little higher. Just connect the positive and negative on the battery with the engine running.

If you have an AutoZone or advanced auto parts they could check it for you, for free.

Reply to
BigJim

Do a quick voltage check (but it may not diagnose a bad diode in a rectifier bridge). And as others suggested, take it to AutoZone or your local parts store that offers free testing.

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There are a number of things to check:

  1. The alternator belt tension. The belt may be loose. For this I'd use the Gates Krik-it II gauge. It about on Amazon or your local NAPA store.
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  2. Connections you mentioned. Oxidation under tight connections can still cause voltage drops. That's why people use .99 battery terminal cleaners, among all the wire connections.
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  3. Alternator brushes. These come in an assembly that costs ~ from the dealer. You might want to check these before replacing the alternator. Brushes wear out after 120-150K miles. The assembly is easy to replace.

  1. Alternator diode bridge/regulator. A bad rectifier bridge can't rectify the AC voltage into DC properly. So you end up charging AND discharging the battery in quick cycles. This will damage the battery. If the bridge/regulator is bad, just get a new/rebuilt alternator, it's more cost effective.

  2. Well, you have a new battery so we assume it's good. Typically ones made by AC Delco (maintenance free, ~) or Johnson Controls (maintenance type, ~) are very good.

Reply to
johngdole

I had alot of similar problems and but my terminals looked clean, so I took one off and it was completely corroded inside , I cleaned it and the battery terminal since you could not see it coroded with the cables on, then it would not tighten and give good contact since over the years cleaning removed to much lead so I cut sheet metal to fit inside the clamp. Check the clamp and how well it tightens

Reply to
ransley

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