1993 Camry LE 4 cyl...

I have had problems with alternators ever since I replaced my OEM alternator a year ago (lasted 250K miles!). I am on my 3rd rebuilt alternator from a local chain store. these seem to last about 3 months before problems arise.

Luckily, they come with a lifetime warranty and cost me nothing but time when replacing. also, lucky these are easy to replace and only take a few minutes..

The first 2 rebuilt alternators failed on the diodes. this one is now failed with the voltage regulator...

Are these aftermarket alternators this bad or could I search for another problem to fix this like a short somewhere or something else...

battery terminals are tight and cleaned regularly, negative connections good on the starter, replaced the thick negative cable from the firewall to the engine head.

I also could pay the extra $50 to upgrade this time to a "new" alternator from the same chain store...


any thoughts???

 

The original alt could have failed due to a diode or regulator issue or the brushes could have been worn out. Worn brushes are common, the others are not. Did you exchange the old from the rebuilt?

Does the car have any additional electrical items requiring a lot of amps such as large aftermarket stereo amplifier?

Does the car have daytime running lights?

Check the wiring connections at the alt and wiring to it. The independent larger wire at the alt routes output power to the 100A fusible link inside a small box. Make sure the electrical connection inside box is OK.

Make sure the battery cables, cable terminals and connection at the battery are good.

Don't operate the engine with the battery cables disconnected.

An open wire can also cause diode or voltage regulator failure. When the engine is running the power output wire from the alt is connected to the plus terminal on the battery via the cars wiring. The negative battery terminal of course is connected to ground. If any part of this circuit is open for a moment or has a bad connection a part can fail.

Other causes of diode failure are jump stating the battery, using too high output setting of a battery charger or reversing the battery cable connections when jumping or charging.

When alts are rebuilt typically only the bad parts are replaced, not all parts. It is possible the alt can be bad out of the box or fail shortly after do to another bad part. Three in a row is uncommon but never know, have had two in row bad out of the box. That's why they offer the lifetime warranty.

If you do decide to upgrade to new make sure the part has the same lifetime warranty.

Check the wiring, etc as stated above.

What condition is the battery in?

A Google search will find posts on checking the alternator output voltage at the battery when engine is running. Check the voltage and make sure it is within range.

You can also check voltage between the small white wire at the alt and ground engine running. Typically 14-15v engine cold, 13.5-14.3v engine warm.

Voltage between the yellow wire at the alt and ground engine off but ign switch on should be 0-4 volts.

 

I do have an alpine amplifier installed...draws 20A. I wonder if going with the new alternator would be a better route due to the amps draw on the power supply.

All that you recommended is in place, aside from a short somewhere that i havent found or diagnosed.

I assume that the aftermarket alternators are using cheap replacement parts inside on their remanu job. These things are made in china, subpar quality for especially using electrical replacement parts.

Also, a while back i had to replace the coil. Used aftermarket and it also lasted only 3 months. I replaced it the 2nd time with a toyota oem coil. No problems at all since and that was last year when i replaced it.

I tend to believe the aftermarket alternators are crap, designed to make a quick buck off the consumer. So many aftermarket parts ive used tend to fail too quickly and seem like crap to begin with. I never have any problems when using oem parts from toyota.

 

I seldom buy rebuilt parts from auto stores for reasons you state.

Tough to be OEM parts.

If you are up to find a OEM replacement at a junk yard having some kind of warranty in case it is bad when removed. Typically unless an electrical issue caused a diode or regulator failure the only thing that fails is the brushes wear out and these can be replaced easily enough without taking the case apart.

Or get the new alt but make sure it has a lifetime warranty.

Try rockauto.com for a better selection of alts and lower prices.

Keep in mind an alt will only put at max amps at around 1500 RPM. If the combination of amps and everything else that needs to be on at idle is too high the battery will be making up the difference.

At night are the head or dashlights dimming when as bass sounds hit. If so the electrical system is under strain.

If not done already might try installing a large capacitor between the DC power and the amp to help. The internet would have posts on this option.