TurboSpider
Proven Member
- 223
- 16
- Nov 2, 2015
-
York,
Pennsylvania
- My old alternator was only outputting around 12.9 volts once car got hot and didn't seem to go up much more with rpm increases so I bought a remanufactured alternator for a 97 galant from advanced auto. Its a carquest premium. When you first start the car and it's cold it is idling around 1100 rpm and alternator is putting out 14.5 volts. As the car starts the warm the idle comes down to the set point in ecm link of around 800 rpm. Voltage drops to 13.5. Once the car is warmed up fully it goes down to 12.7-12.8.
I have done lots of searching on here and have seen many people saying this is normal and then again lots of other people saying it should be 14.5 all the time even at idle. I found in the alternator section of the service manual it gives different voltage output readings in relation to engine temp. With the highest temp range showing around 13.1 volts out put. That seems to sorta agree with the its normal. I also saw that advanced auto rebuilt alternators are junk from several people and that it isn't uncommon for people to have to exchange alternators several times before getting a good one.
Since I am using the 90 amp galant alternator I am wondering if it is regulated to not start outputting voltage untill 1,000 rpms because maybe the galant has a higher factory idle then a 2g eclipse? Maybe that could explain why it comes alive once the rpms come up a little?
Anyone else with a galant alternator have similar experiences? When my idle comes down to normal idle speed you can actually see the interior floor lights dim slightly and they get brighter when it's reved up. I have seen mixed things when searching but am starting to think the voltage regulator is not working. I also saw there is a generator relay, that I haven't really done anything with. The battery light does come on the dash with key on engine off although it glows dimmer then all the other warning bulbs
I have attached an idle log that shows how the voltage decrease as rpms come down