Busted Alternator... Suggestions?

[Nexagen]

The car: A 2000 Mitsubishi Eclipse 2.4L SOHC with 79,000 Miles

Upgrades: Cold Air Intake, Magnaflow Exhaust, NGK Iridium IX Sparkplugs, Magnecor Ignition Sparkplug Wires, Falken Azenis St-115 Tires mounted on X<9Lbs Racing Rims 17 inch.

Weight Reduction= Spare Tire and jack removed

Est Hp= 175+

The Symptoms =
Car starts fine but after 2 seconds of idling chokes and wants to shut down. RPM gauge reads 700 at 1st second then 2nd second reads 500 and 3rd second goest to even 200 RPM then goes back up to 500 RPM and wants to stay at that RPM level.

When the car is running at 3000 RPM it runs fine and accelerates fine. But feels like it wants to shut down after coming to a 0 MPH stop.

The Blood and Sweat:

6 Quarts of Royal Purple 5W30 with a can of Engine Restore
14 Quarts of Royal Purple MAX ATF ( Automatic Transmission Fluid )
1 Pint of Chevron Techron Fuel Injection Cleaner every tank full

The Power:
Diehard Gold Battery Group 86


THE PROBLEM:

I had the Sears Diehard battery tested at a local Autozone and tested out at 12.6 volts or something like that. All the electronics such as lights and radio appear to be working fine when key is in ignition.

So upon this test I concluded that it was not the battery that was causing the problem.


I then removed the negative battery cable and the car shut down the moment I took it off the battery terminals. I tried this again a second time and the same effect happened.

My conclusion is that the Alternator is causing the problems and I will need to replace this.

I wanted to know where it is that I could replace this besides the dealer and I am looking to spend LESS than $175 just for the part.



Also any suggestions supporting or otherwise to my problem would help.
Like a website address or something.

Once again the car is a 2000 Mitsubishi Eclipse 4 Cyl.

Thanks and any help is appreciated!

-Nexagen

[BeEfCaKe]

Look around, there should be alot of places that sell rebuilt alternators... those are pretty cheap..

[INF3RN0666]

Alternators are mostly universal. Go to a junk yard and get yourself one for $30-60. Obviously a new one would yield slightly better performance, but you'll never notice it on a 4 Cylinder. I get mine rebuilt for $75. Installation costs depend on where you get it installed. When it comes to something as simple as an alternator, the cheapest garage can do it as good as the dealer for a cheaper price. AND SOMETIMES, the people at cheap garages know more than the dealer (trust me, nobody can figure out why my transmission kept busting except for the people at my cheap garage).

[Rufe]

There is a voltage regulator that is part of the charging system. This is usually built into newer alternators (ie. not replacable seperately). If it is a separate part on your car, start there first.

You might have the Autozone (or whatever shop will check it) check the
output from your alternator, to be sure. I think Advance Autoparts will check this for free.

Be careful about ruling out the battery completely, the radios, lights, etc. will often work fine on a low battery, even if only a few of the cells are at 12volts, car not running. It works in conjunction with the alternator and voltage regulator. I have seen a bad battery ruin a new alternator, and vice versa. Make sure all your connections are not corroded. However, since it runs fine at 3,000 rpm, I would agree with you that it is most likely the alternator, it seems to not be sending enough output at lower rpm's.

I agree with the above, a rebuilt alternator is as good as new, at less cost. It is not difficult to change.

If that fails, you might check the fuel system. Are the lines and filter clean, is the fuel pump working properly?

[MagicRat]

Where to start.........
That you have described is a 'logical fallacy'.
It is etremely unlikely the alternator is related to your idle problem.
Many cars will stop running when you remove the battery terminal. Not all alternators will keep the car running without a battery hooked up (even a bad one). It is a function of the wiring that some cars have.

If your alternator produces 13.7 to 14.5 volts with the engine running and the lights on, its fine.
More than likely you have a problem with the throttle body, and especially the idle air bypass valve. This valve controls the idle speed of the engine. These require maintenance, such as cleaning. They mostly get dirty due to the PCV valve.
I would suggest taking it to a mechanic who can scan for codes and clean the throttle body.