Alright i just took out my alternator i thought it was bad and i brought it to two places to get tested and it's fine. So i bring my battery to get tested and it's dead. So i buy a new battery. This whole thing started because my voltmeter was reading about the redline so i thought it was my alternator but i was wrong. Now it's doing about the same thing even with the new battery. When my fan kicks on my car wants to die. Any suggestions and what does your meter read. Right now mine is a little better than it was it's a little above the red. It used to read in the middle. Any suggestions or replies are appreciated.

 

First measure the voltage across the battery while the engine is running. It should be around 14 volts. Then check the grounds at the frame and the engine to be sure they are shiney, tight and unbroken. Check the positive cluster on the fender too. Then take the reading on the battery again with the engine running and let us know what happens.

 

My 95 Z28 A4 has a low voltage problem to. It runs OK but not up to full par. Had the alternator and battery checked, I cheched all the connections everything s seem ok. I've been over this a few time already. Datamaster scan shows it droping down in the 11 volt area. Not good. I'm about to change the alternater out.

 

Yeah i'm prob going to change the alternator. I'm going to check all the grounds one more time. I think that might be my problem. I had my alternator checked by a reputable place so i think it might be a ground. I"m going to go and check it out right now.

 

check out my post about 230/236 and heads with low dyno numbers. My car says on the scanmaster and the volt gauge that the car is only putting out 12.5 volts. I had the alternator checked and it is putting out 13.5-14 volts. People are telling me to check my fuel pump to see if it is eatting up all the juice. Check out the post. By the way my car has 138k on it.

 

Just went through a similar problem. Car would dip down to the red with the fans on. With a volt meter i was getting 13.2 on the alt while idleing. The battery was new and the alt test fine at two different places. Went through and cleaned all the grounds. Disconnected all aftermarket equipment nothing helped. Finally took it to an independant alt shop he tested it, and it still came up good so he took it apart and the post that connects to the battery was loose put a new one in, and the thing works great now. So I don't know how much faith I would put into the alt tests.

 

I have the same problem - see my post
http://web.camaross.com/forums/showt...&highlight=bat

sounds like the scanmaster reads about 1 volt low.
Anyway my Alt and Bat were tested and are OK so it must be a gauge issue

 

Late night coming home from the car show. I put my fog lights on and my voltage dropped a little. No big deal. As I stopped at the store I noticed my headlights dim for a second. My voltage on my meter that plugs in to the lighter was all over the place. On the drive back to my house I started to think about it . When the alternator heats up the voltage starts to drop. So every time I take it to get ti checked out it cool. When it heats up is when the problem shows. I'm going to buy a new alternator.

By the way, If your looking to buy new parts I found this site BYUNSPEED.com This guys prices are just about the same or if not better then anybody on the web. But the kicker is he don't charge shipping or handling.. I buy a lot of my parts on the internet, And this guys has been tops with me.. Check it out for your selfs. BYUNSPEED .com

 

Yeah it's fine when i first start it up but when it gets hot it drops like you said....looks like i'm getting a new alternator and my car just died on me. I mean all the stuff turns on like the headlights and interior lights and my keyless entry still works but everything that requires the key like the radio and to roll up the windows doesn't work. Oh well thanx for the replies.

 

That sounds like your ignition switch.

 

Yeah i'm hoping it's the ignition switch and that's all. I mean everything works but like i said the fuel pump doesn't come on and none of the dashboard lights come on like right before you start it and the windows won't roll up and the radio won't turn on but it tells me the time It died on me for like 20 secs but then it started right back up and then i was driving again and it died like 2 mins after. Well thanx for the input.

 

Scanmaster voltage is what your PCM sees, as voltage runs through the system there is a voltage drop accross all the components, by the time the PCM/fuel pump sees the voltage its no longer 14 volts, yet the alternator will not see this as a big load since the further away the drop is after the alternator/more system it goes through the less sensitive the alternator becomes & won't generate as much current.

I noticed the biggest voltage drop in the system occurs at the fuel pump, as the wiring ages & so does the pump, the pump draws more power & the wiring becomes degraded & the voltage drop accross the system becomes pretty big, the alternator barely sees this & so it doesn't really compensate.

Easy fix is buy the Racetronix Fuel pump wiring kit, just the wiring kit which is a 10 gage wire that comes right off the alternator terminal & goes all the way to the back to a relay, the stock fuel pump connector is now only used to energize the relay & the relay feeds the fuel pump off the 10 gage wire comming off the alternator. I did this & my voltage in scan master went from 12.5 to 14.1 in the morning & once she warms up to 13.6 steady which is where the voltage should be at operating temp. At the battery I'm reading around 13.9 when she warms up, so now I only get like a .3v difference between system voltage (what scanmaster reads) & whats at the battery.

This also fixed my fuel pressure problem at WOT, the pump only saw 12.5 volts at WOT & my fuel pressure after 5k would drop with all my mods pretty hard, after i did the racetronix wiring mod my stock pump stays at 43psi from 1k-7krpm without even blinking cuz the system voltage is high now & alternator is compensating for the draw properly.

Matt.

 

My fuel presure is fine, and my voltage drops down to 11 volts and sometimes 10 volts. After drive for 20 min. or so.

 

Anyone have a part # for an aftermarket alternator ?
140 volt.