Alternator Issues.
 

When I start my car the voltage is pretty good(in the 14s). But it after awhile the voltage goes way down. We are talkin 12 volts or less(yesterday it was 10.8V). I dont know if its because the alternator is getting hot or what. Here are some spec on my car that might help

New alternator(<2 years but only 1500 miles TOPS)
New battery
Battery in trunk
0 guage wire from trunk to front for power
4 gauge ground from battery right to chassis in the trunk
Alternator has a ground wire to chassis
New power wires from fuse box to alternator
New alternator belt
JMF heatshield on manifold
Homemade heatshield on O2 housing

Im thinking that its either a bad alternator OR I need to run a ground from the trunk to the front. Anyone have any other ideas

Re: Alternator Issues.
 

How is your car idling? Does the voltage go up or down with the RPM?

Re: Alternator Issues.
 

+1, if you up the rpms, does voltage go up? Could be your voltage regulator going out. Double check that you have good connectivity on all of your connections to bare metal, not a painted surface.

Re: Alternator Issues.
 

My alternator wasn't new, but it was rebuilt in about 2 years. Starting the car, i'd have to step on the gas for a lil bit to have it go up in the high 13 to 14. After awhile of driving, it'd drop to the 11's - 12's. The dash lights would also go on about this time. Let the car sit for an hour or two and it "MIGHT" be ok. I went to LSE one day to pick somethin up and on my way home, the voltage went to the 8's, my lights went out, got home, turned it off. Car's dead.

I'm thinkin it could just be your alternator, but try the tips above.
After I replaced mine, it now runs like a champ. Except for the squeeky belt. been too lazy to fix that.

Re: Alternator Issues.
 

Alternator fuse or voltage regulator in the alternator is going bad.

Re: Alternator Issues.
 

I had about the same problem. Mine ended up being the alternator fuse, but I got a new alternator just to be safe.

Re: Alternator Issues.
 

Ill check the fuse but Im pretty sure I checked it when I moved the fuse box. The voltage does go up a bit when off idle but at a constant speed/rpm its goes down. Im pretty sure I have a lifetime warranty on the alternator so maybe Ill replace that.

Re: Alternator Issues.
 

I go through alternators like skittles, well at least one a year. but I have a lot of accessories to drive, gauges, fuel pump, two big spal fans, and everything else in use during the day. are there any bigger alternators your can get for these cars??

Re: Alternator Issues.
 

I heard that the cars that were sold in Canada had to have a bigger amperage alternator because they were required to have daytime running lights standard. I could be wrong but I remember hearing that.

Re: Alternator Issues.
 

Yah if I remeber right the stock ones here are like 75-80 amps and the canada ones are 90 amps.

Re: Alternator Issues.
 

I looked at higher output alternators for DSMs. If you want to pay $350 you can get a brand new Bosch 160amp for these cars, and there is the larger "canadian spec" 90 amp also, as said above. If i remeber, maybe galants (maybe vr4s) had a larger alternator, I dont know that as a fact.

Re: Alternator Issues.
 

Galants are 90amps. 1g automatics have higher output alts than the manuals as well.

Re: Alternator Issues.
 

I just checked napaonline and the NA 2gs have 90 and the turbos have 75. WTF why do they get the 90? Fricken non tubros! :)

Re: Alternator Issues.
 

I paid close attention to the voltage on my way home from work. Here is how it went:
Started and it was 14.4 at idle.
Started moving and it went up to 15.4
Then back to 14.6 at idle.
cruising at 3000 rpm it was at 15.0ish
after about 2 miles(4 min) the headlights went dim and the voltage dropped to 13.0 while cruising at 3000rpm.
after that idle was about 11-12

Re: Alternator Issues.
 

So if I purchased a 90 galant auto alternator would it bolt up? I have a 1990 GSX. I also have the alternator relocating kit, if that makes a difference?

Re: Alternator Issues.
 

Went to uni last night and on the way there the voltage kept dropping. Got down to 8.X volts. So I took the ALT out and brought it to napa and they tested it and it doesnt put out any voltage. A new one is coming on moday!

Re: Alternator Issues.
 

I was having the same issue too. Drove it around for a year and than the three dash lights came on. Scared the crap out of me so I replaced the alternator. Now I am happy except for the dam squeling I can't get get rid of. I think it is time for a new dampner pulley. Glad you are getting it replaced though.

Re: Alternator Issues.
 

Replaced it on monday and it charges at a steady 14 Volts. I still need to tighten the belt a little more but all is good. I think driving it around like I was F'd up the battery tho. When I get in the battery is only at like 11.7 Volts.

Re: Alternator Issues.
 

The battery voltage should be 11.5-12v when when the car isn't running.