Bad Alternator?

[98mitsubishigst]

Okay so i have a 98 Mitsubishi Eclipse Gst Auto

The last 3 months i would have the brake light and battery light pop on and off when driving and it would go off alot but then sometimes it would stay off then sometimes it wouldnt come on at all. . .

Well Just recently i fryed a battery and replaced it (installing subs and amp)
Then after that a week later i went outside and it wouldnt crank on at all no lights no nothing..
I got my buddy to jump start it and it worked for a 3 days didnt think anything of it but then today i went to get my Megan racing catback put on and it died later that night while it sat in the garage.

Jumped it . and couldnt turn lights on at all. or it would cut out same with radio... if i flickered lights car would die or sit on a hill going up i would stall out... Lights would be real dim radio would turn on and off. . . Got the car home to driveway turned key to electronics and car died....



Bad Alternator?? and would this be hard to replace by myself?

 

[Tyeler18]

sounds like it, seems like your running off the juice in the battery

alternator shouldnt be real hard to do yourself, just have to make sure nothings broken and that you put everything back on in reverse order

 

[98mitsubishigst]

o and i forgot to put in the biggest part!!!!


that alternator was put in 10k miles ago...
what could it be? could it be the alternator?

is it possible?

 

[booostedGSX]

+1 on the bad alternator. I had the same problem with my 1G. You might as well change the battery and alternator belt too so you can prevent a future headache.

Also, changing the alternator isn't hard as long as you take your time and remember what you did so you can put it back together correctly. It should be a cinch

 

[ClevelandDSM]

Well Just recently i fryed a battery and replaced it (installing subs and amp)

Expect a lot of extra work out of the charging system while running things like this. Running a ton of power off a factory charging system is a double edge sword.

 

[98mitsubishigst]

Im pretty sure its the alternator we had to jump it 4 total times in a week..

alternator must not be charging my 2 batterys that ihad total for this car...


Any other comments?

 

[91dsmgsx]

you never mentioned if you checked over all your fuses, grounds, and connections one way to test the alt. is to run a jumper wire from the pos. of the battery to the output of the alt. if the alt is working the small jumper wire will get very hot very fast. if the wire remains cold or just warm your alt. is putting out enough amps to charge your battery

 

[98mitsubishigst]

okay so everyone wanted 400 bucks go get a new alternator put in so me and dad took out the alternator and got it tested and was gonna get it rebuild.. well it so happens that the alternator was perfectly fine...

what else could it be... my terminal to the battery looks like shit

could that be the problem?


HELP PLEASE I WANNA GET MY CAR RUNNIN AGAIN
and another problem is its been 0 to -10 degrees up in pittsburgh lately as well

 

[vanilla gorilla]

Just because a test at autozone or advance shows that it was good, doesnt mean its good. Theres too many variables when dealing with alternators. Testing alternators does nothing. If the test shows that the alt is bad, then its bad, but if it shows its good....its a good possibility that its still bad. For instance if the internal voltage regulator in the alt is bad...then the alt can charge fine sometimes, then sometimes it wont....and when you put it on the tester...it shows good output. So again you cant really go off those tests. $400 is ridiculous.

You should run some deep cycle batterys in your car, to reduce the stress on the charging system, since you are running audio.

 

[98mitsubishigst]

i got it tested off a store that focuses on alternators..

 

[vanilla gorilla]

Ok, it may be good then.

Do the test described in one of the previous posts, pull the positive cable while the car is running

 

[98mitsubishigst]

idn the wiring to the pos terminal is half out its frayed out i mean
...

and the terminal looks like shitt

what would this do if i pulled it?

 

[vanilla gorilla]

Start by putting a new terminal on it...

 

[Defiant]

Do the alternator check...

...which would consist of you jumping the car...while its running pull the positive off the battery, if that car stalls out, then your alternator isnt making electricity and has gone bad, if it stays running then you know your alternator is ok.

It simple and easy.

Simple and easy way to fry the electronics of any car built after 1980.
DO NOT DO THIS WITH A MODERN CAR.

 

[98mitsubishigst]

Alright so.

Dad and I took alternator out in 0 degree weather and found out the alternator was perfectly fine the girl that owned the car before me got one installed right before she sold the car to me it has 10k miles on it...


seemed to me like the terminals were bad and replaced them...
car starts

haha i was excited i filled up my oil power steering anti and brake fluid and was good to go drove up to Advanced and they told me my battery was bad.. Brand new battery and they said its bad because it drops from 14 to 13 volts when i turn lights on... its a 12 volt battery dad says that is fine..

just looking for a oppinion

its been a week now since car has been running too so idn

 

[BlazeGT4]

For future reference, the fastest way to test for a bad alternator is to start the car (jump if necessary) then pull the negative cable from the battery. If the car dies immediately, then your alternator is likely bad. The only exception for this would be if a fuse is also bad (for get which fuse/relay it is but you could look it up).

Make certain you have your battery tested (if you haven't already). Also be certain is has the correct cranking amps for the car. A honda CVVC battery can probably start an ///M3, but its not made for the car and will have a shorter life expectancy.

Since you're running a big stereo, you may want to consider upgrading your alternator at some point. Pick up a Low Rider magazine and I'm sure you'll find a company that will either make you one, or rebuild your existing one to spec. In the mean time, I would think your amps could be suspect.

I would try disconnecting your stereo fuse, plus the fuses on the amps and see if your problem doesn't go away. If something is hooked up to a constant power, this could drain your car over night. Another "simple" way to test for a power drain would be to disco your battery over night. (obviously an electronics diagnostic would be the preferred method) but if you don't have time or any familiarity with an ohm meter, this is a good way to see if this is the case.

good luck

 

[LandoAWD]

For future reference, the fastest way to test for a bad alternator is to start the car (jump if necessary) then pull the negative cable from the battery. If the car dies immediately, then your alternator is likely bad. The only exception for this would be if a fuse is also bad (for get which fuse/relay it is but you could look it up).

Make certain you have your battery tested (if you haven't already). Also be certain is has the correct cranking amps for the car. A honda CVVC battery can probably start an ///M3, but its not made for the car and will have a shorter life expectancy.

Since you're running a big stereo, you may want to consider upgrading your alternator at some point. Pick up a Low Rider magazine and I'm sure you'll find a company that will either make you one, or rebuild your existing one to spec. In the mean time, I would think your amps could be suspect.

I would try disconnecting your stereo fuse, plus the fuses on the amps and see if your problem doesn't go away. If something is hooked up to a constant power, this could drain your car over night. Another "simple" way to test for a power drain would be to disco your battery over night. (obviously an electronics diagnostic would be the preferred method) but if you don't have time or any familiarity with an ohm meter, this is a good way to see if this is the case.

good luck

Goddamnit, read the WHOLE thread.

This has the potential to cause extensive electrical damage.

The very next person that recommends this gets a warning.

 

[anteversion]

there's a better way to test an alternator than to disconnect the battery and risking to put her down. Putting a battery down is not good for the longevity of her life. Just start the car and with a voltmeter probe the positive of the battery and ground the other probe. You should read near 14 volts on the voltmeter... if is the case : the alternator is doing his job. If not, it can be 2 options: bad alternator or bad connections.

To localise a bad connection: probe the voltmeter at the wire terminal that come from the alternator and then with the other probe, test each other terminal that are in between the alternator and the battery ( fuse box in and out, and terminal that goes to the battery. you should have 0 volts in the best of the world. every volts that will be reading is a sign of potential difference, wich means too much resistance, wich lead to bad conductivity of the voltage

 

[96mitsugsx]

Good job on the terminals! I've seen that happen to 3 cars already.