Weird Charging Issue - ALT???

[PROJECT240SX]

Hey guys,


I have had some weird charging problems the past few months. Little background on the car: It is a 1989 SOHC, was originally an AT but swapped over to a 5spd(used 5spd harness).

I only drive the car maybe twice a week. Well the first time I had a problem I had my battery tested and it turned out it was "Bad", I replaced the batter with a new one and car ran fine.

A few weeks later the car just completely died while I was driving it. Had the alternator tested and it came back "Good". Had battery tested and it was "Bad". They ended up replacing the battery under warranty. So I figured problem solved.

Shortly after this incident car died again, went over the car and found out that my negative battery cable was loose. Charged battery, replaced all terminals, added extra ground, and tightened everything down.

So this week I drive the car and low and behold.......it dies!! Check it with a volt meter and the volts go from 11.9volts in off position to 3volts when car is turned over.

Jump the car and drive it home. Later today I jumped the car and as soon as I removed the jumper cables it dies.



I am starting to think it may be something with the 5spd tranny harness that I used. Thinking of switching to a AT harness to see if that will solve my problem. Any help would be appreciated.


CLIFFS:
Had numerous charging problems
New Battery
Alternator tested Good
Volts go from 11.9v to 3v when key is turned to "ON"
Car dies when jumper cables are removed

[SoguRacing]

Maybe you alternator is bad. i know you tested it but sometimes they work and sometimes they dont. in order for your battery to charge your computer needs to see at least 12.4 volts. I think that maybe you have an open circuit somewhere seeing that you've used 2 new batteries and the same thing happened. check the connections to the alternator and see if all the connections are solid. turn on the car and check to see if the battery voltage is around 14.1 to 14.4 volts. thats normal while the alternator is working. lmk what happens

[just1pepsi]

easy alternator test:
Start vehicle, disconnect positive battery terminal , if the car runs the alt is most likely good. if it dies, then the alt is bad.

It is also possible however that regulator in the alt is bad. an alt test may not necessarily reveal that. Also if you have done any of the wiring yourself, you may have something powered when the car is off that is draining the battery. Since you only drive it acouple times per week, that would kill the battery.

[Coupe_Love89]

yeah if the reg is bad the alt could actually discharge the batt

[PROJECT240SX]

Here is a little update guys:

Went to the parts store and picked up a new alternator today. After installing it I started the car and checked the voltage and I was a 11.67V.

Then checked the voltage at both negative and positive cables while the car was idling with following results:

Negative = .01V, anything under .03V is supposed to be good.
Positive = .01V, anything under .07V is supposed to be good.

I monitored the voltage at the battery for about 5 minutes and the car just continued to lose voltage, ending up at 11.48V when I decided to turn it off.

So.......... I am thinking that it is more than likely my 5spd wiring harness. I will be picking up a AT harness as soon as I can find a clean one.

On a side note, shortly after I started the car it began to overheat. It has not overheated once since I owned it. That was the reason I turned my car off after only 5 minutes of idling. I had my A/C on while the car was idling but there is no way that should cause my car to over:-/ Car is driving me nuckin futs.



Ivan

[downshift_sideways]

Wow this car is a monster Ivan!

Has a life of it's own!

[PROJECT240SX]

Wow this car is a monster Ivan!

Has a life of it's own!

Tell me about it! I'm about to ghost ride this mofo off a cliff.