2G 99gsx Possible bad alternator.

[blazin_teg]

I think my alternator may be going bad. I have not had a battery light come on yet. My dash lights get dim when at a stop light. When I leave the light they brighten back up. But while accelerating get a few dim dash light moments. For about 1 second maybe. So I tried testing voltage. 13.75 at idle no accessories on. With ac and headlights on it drops to 12.20 at idle. To me this seems like its not that bad. But not great either. Also I read where some people experience flickering lights. My dash light will flicker when I hit the right turn signal. One more thing to add. It dosent feel like it has all the power it should. Checked for boost leaks fixed them all. New coils ngk plugs and wires fuel filter and fuel pump rewire. About 150 psi compresson across the board. 154000 miles on it. Its like somethings choking it off. Has very little power with no boost. If my ac is on I got to give it alot of gas and it just wont accelerate then boost comes in and it picks up suddenly but still dosent have much pull to it. Im all factory except for a cone filter. I have owned turbocharged cars in the past. My stock rb20 was pretty damn quick. I cant even beat a 98 stock suburban in my car in this codition. Thats what one of my friends from work is driving now til he finds a car. So come on guys help me out.

 

[arodgst]

I had the exact same problem, I took off the alternator and had it tested at autozone for free and it failed 3 times, you can do that to be certain and it's free, and you could have some grounding problems, are your ground and power wires nice and clean? Just something to look for.

 

[blazin_teg]

Everything appears to be clean. New brass battery terminals. Appears to be a pretty new battery. And underneath the rubber cover where the wire bolts up to the alternator looks almost new. No oil on the alternator, it actually has a very clean look to it like maybe it was replaced. I did have an alternator pr terminal code. I unpluged the harness cleaned it a little put it back on and I havent got that cel again. Only cell I have now is fuel pressure solonoid. When I first got the car about 2 months ago I had the alternator tested at advance auto. It was one of them testers that gives you a pass or fail printout. starter battery and alt all passed. But this was about 2 months ago. Had it tested because of pr terminal code. If its not the alt, only other thing I can think of thats causing such a power loss is maybe phantom knock. My flywheel sound like the bolts may have backed out causing some clunking sounds. I had some timing issues when I had my rb20 s14. Had a bad front knock sensor and it would boost hard and sound mean but just wasnt goin nowhere. I could advance my cas all the way and it would pick up power. On the s14 that is. But from what ive read the ecu adjusts out base timing.

 

[Kris_TM]

You do not have to remove the alternator to have it tested. Just drive to any autozone or discount advance auto parts and they will test your battery and alternator on the car. Save you a lot of un-necessary hassle.

 

[nuclearr]

You either have a bad alt or battery. You should take off the alt and have it checked. Also while the alt is out have the battery tested out of the car. Once you have determined they are good put them back in and have it tested again on the car. If you fail you have cable issues. Make sure they check it at idle, not just the 2-3k rpm range.