Taylor

Hi, I have a 95 formula A4 that I believe is all stock. I just got it a couple of weeks ago. I am out of town with the car and I noticed last night that when I am stopped in gear idling with the lights and a/c on that the volt gauge will drop almost to the yellow, but it I put it in neutral or rev it up to about 800rpm and the gauge goes back up to just over 13 on the gauge. I hooked my laptop up running datamaster to verify that the gauge wasn't messing up and when the gauge would drop, datamaster showed about 11v. I took it to the oreily's here and had it tested and they said the battery had a bad cell so I replaced it but it didn't make much of a difference. The volt gauge reads above 13v any other time other than idle. I cleaned all the grounds and positive junctions on the fender by the battery and replaced the bolts for the battery cables. The computer at oreily's showed the alternator was putting out 14v at idle in park and that there wasn't anything wrong with it. I was wondering if you guys have any ideas?? I only have basic hand tools with me and don't have my DVM with me.

Thanks

Taylor

Taylor

I got back home and did some testing with my DVM and datamaster. I put the car in gear and turned everything that uses battery power, I checked the voltage at the battery while it was running and it was right around 13v while datamaster said around 11.2v and the gauge was in the yellow. Does anyone have any ideas why it would be like that?

Thanks

Taylor

Green96Z

The data read for voltage is going to read lower than at the battery because stuff in the car is pulling current. Check to see if the previous owner put an underdrive pulley on there.

Taylor

I pulley looks like the stock pulley. I can understand some voltage drop but I wouldn't think it would be almost 2v. I really only noticed this problem since Friday night it was fine before then. I am going to check the voltage in and out of the ignition switch to see if the drop is coming in there.

Taylor

Taylor

I did some testing at the ignition switch and getting about .10-.15v going threw the switch I don't know if that is to much or not, I had slight discoloration on the blue plug that plugs in the ignition switch but it wasn't to bad. I am at a loss, maybe I can put a different pulley on the alternator to get some more voltage out of it, does anyone have a part number for what I need??

Thanks

Taylor