Signs Of A Alternator Giving Out ?

[Joker]

I was coming home from the probation office and was driving down the road normally , stereo down just to where its audible and I look at the voltage reading off my headunit .. reading 11.9 - 12.1 volts .

It has done this too me before around november '08 , stuck in a traffic jam and the voltage reading was 14.1-14.4 one second and then I glanced back at it and its dropped to 11.9-12.1 then the little battery light comes on . Then all of a sudden it shoots back to 13.7-13.9 -14.1-14.4 like it was no big deal and the light disappears . It did this at a low engine idle , engine normal temperature and stereo at a audible level like today .

Now on my way there I was banging it etc then turn it down . My battery is about 6years old , not sure if that could be causeing it ? Car starts right up so I figured the battery was cool .

Im worried now though with it doing it while the car was cruising down the road , engine rpm 2,000-2,500rpm . Just stayed at 12.1 like it wasnt charging only running off battery power or something . I pushed in the clutch to see if it was belt slip and had the same reading . Then with the clutch pressed in still rolling down the road I reved it to 4,000rpm and held it and immediately it read 13.7-13.9 14.1 14.4 etc , let off of the clutch and it dropped back to 12.1 .

I was in a bad part of town so I was hoping the damn car didnt die out on me and then all of a sudden it reads 14.1 -13.9 volts on the rest of my drive .

I then drove it about 30miles and everything was fine , turned the car off and it restarted . When I pulled into my driveway I seen the little battery light come on and sure enough the voltage was 11.9-12.1 . I hurried up and popped the hood and looked to see if the belt was slipping or something and it was turning just fine . Then it all of a sudden goes back to 13.9-14.1 volts like nothings wrong and I recheck how the belt looks with good voltage and its tuning the same as before .

The alternator I bought off ebay , supposed to be new and it looked new when I installed it around summer '08 , its supposed to be a 170amp unit .

Not sure wtf is going on with it

[lolitskasey]

My car is doing the same kind of thing but not with the voltage. When i turn up my system yp loud my RPMS would bounce around and my car would stall some times. But i figuer that the reason mine is doing this is cause i havent put a batt in the back of my car yet.

Edited April 1, 2009 by Eric B
No need to quote the whole thing

[Joker]

I was driving the car in feb'09 and all of a sudden it stalls on me .I tried to restart it and nothing . I was sitting in the middle of the road so I had to push the car off to the side . Popped the hood to make sure the engine didnt go on me , everything looked fine . Headlights would come on bright , interior dome light was normal brightness so I figured the battery was cool .

The car had gas showing 1/4 tank on the needle and I have run it until the light comes on before . Guy and his wife pulled over to help me and I tried to jump start it just to see if it would help , it turned over a little faster than normal but wouldnt crank up . I finally called for a ride and I went and filled up some gas cans thinking maybe the gas gauge stop working . When I got back to the car I popped one of the ignition wires off and had my rides driver turn the engine over . Didnt see any spark , gas wasnt helping this car get home so I had to pull it .

Turned out to be a bad ingnition coil . Put a new one in and it fired right up .

[Joker]

Im thinking the internal voltage regulator in the alternator is going bad , what you think ?

[J00bles]

possibly. i've been having a similar issue with my car (a honda civic)

it will read fine, but sometimes my voltemeters will show that the voltage has dropped from 14.2 down to 12.2 with all of my accessories off except for my system playing at a low voltume. this problem doesnt occur at idle, its always while driving my car at speed.

i have thought that maybe my alternator was going out, but have not found out if its the case or not.

Edited April 1, 2009 by J00bles

[MECHMAN]

Depending on what family alternator is, it could be a loose internal connection, or regulator connection. Check the alternator plug, and all cable connections for loosenes or corrosion.

[Joker]

I just checked the connection / plug and its all good and tight . Fired it up and 14.5-14.6volts at a cold engine temp , idling 1600rpm .

But that dont really say much as they all putout killer voltage when cold .

One thing I wanna change is the engine to chassis ground , right now its in the same spot as stock but its all Kicker 4 gauge .

The stock location is the front radiator support and its pretty thin . I am going to move it to be bolted to the strut towers , seems the metal is 3 times as thick there and thats where my battery to chassis ground is . Should help a little .

I have enough 1/0 Knukonceptz Fleks powerwire from my other car and I want to upgrade to that instead of the 4gauge . Should help a little .

MECHMAN hows this for output lol , I dug and found all the info reciets / warranty info etc on this alternator .

Not sure what size pulley it has but it says common ratio is 3:1 and to divide alternator rpm by 3 = engine rpm .

So from the sheet they sent with my alternator showing its output this is what is puts out ~

533rpm - 5.6 amps

600rpm - 24 amps

667rpm - 41 amps

833rpm - 76.5 amps

1000rpm - 101.1amps

1333rpm - 129.2amps

1667rpm - 148.8amps

2000rpm - 161.7amps

2333rpm - 170.9amps

2667rpm - 175amps

I am not dogging the company cause I have the same brand on my other car , 200amp buts its on a LS1 V8 with 6rib belt .

I have had it for alonger period of time and I have had nothing but good voltage with it .

This little unit though just won't cut it for the Sundown SAZ-3500D I have coming .

Keep in mind this little 1.8L 4cylinder idles 600rpm at full temperature .

[Gotloud555]

I think the problem is your battery. A weak battery can weaken an alternator. The alternator isn't putting a correct voltage. It should be higher than 14.6. Atleast 14.7. Take your vehicle to autozone or any mechanic and let then run a tests so it will give you an idea if your charging system is running O.k.

[MECHMAN]

I

So from the sheet they sent with my alternator showing its output this is what is puts out ~

533rpm - 5.6 amps

600rpm - 24 amps

667rpm - 41 amps

833rpm - 76.5 amps

1000rpm - 101.1amps

1333rpm - 129.2amps

1667rpm - 148.8amps

2000rpm - 161.7amps

2333rpm - 170.9amps

2667rpm - 175amps

I am not dogging the company cause I have the same brand on my other car , 200amp buts its on a LS1 V8 with 6rib belt .

I have had it for alonger period of time and I have had nothing but good voltage with it .

This little unit though just won't cut it for the Sundown SAZ-3500D I have coming .

Keep in mind this little 1.8L 4cylinder idles 600rpm at full temperature .

Looks to me like you're just maxing out the alternator. It could be a number of things causing it to charge intermitently. A 6 year old battery isn't going to help, but it seems like the unit is turning itself on an off for some reason. (probably a bad internal connection)

Edited April 3, 2009 by MECHMAN

[Joker]

I went and has the battery checked and it kept saying replace battery lol , so I think thats what I am going to try first .