My 89 GTA now has a first gen 350 using none of the computer electronics the car came with. I have a single pulley alt. with the main power wire and the 2 prong plug. My battery keeps going dead and I am sure it is in the wiring. Should both of the red wires on the alternator be "hot" with the car off? As I look at all the wiring schematics I am not sure how they help as most have been circumvented. The car starts and runs all the electric features work(P/W,P/L,HORN,LIGHTS, ETC). I don't think the alternator is charging the battery but I had it tested so I think I have missed a step somewhere. The battery is new as well. Anyone else run into this?"

 

Well, you named your thread right.

Welcome to TGO. Please don't take this the wrong way, but I think you've got questions you haven't even asked yet. So I'll try to help, but I'll have a lot of questions for you as I try to help you. First of all, do you have a volt meter (a test light will NOT help here)? If not, buy or borrow one before you continue. You'll never be able to tell 12.0v from 13.8v with a test light, but the difference between those two voltages is indicative of whether or not your charging system is working.

When you say the battery is going dead, how often is it going dead and how often are you driving it?

Your question about the alternator wires having voltage/being hot with the "car off" needs some clarification, is the "Ignition On, Engine Off" or is the "Ignition Off" when you measured voltage there? To give a basic answer to that question - The main B+ cable at the generator will be hot at all times.
Are you using 2 wires in the 2prong connector or just one? What do you have those two wires connected to? It should be to a switched Ignition source (usually through the Volt/Battery idiot light) and the other is a Sense signal which is connected to the B+ (hot at all times) circuit. There are plenty of schematic diagrams on Google Images to show you how that should be connected.

This is how you can determine if the alternator is charging: With the engine running, you should have 13v-16v at your battery posts if your alternator is charging.

Once you've confirmed that the alternator is connected and charging properly, then we can talk about measuring for excessive parasitic loads.

 

14.9v running. I try to start it once a week. If I leave the battery hooked up it is down to 60% charge within a couple days or less. I have done the" hook up the meter to the ground" and pull individual fuses and there are no fluctuations in volts. I have even tried pulling ALL fuses and it still goes dead. 2 wires with one going to dash gauge(which seems to work) other to starter and the heavier red wire from alt lug going to same connection on starter which includes the main batt. cable. Both of the red wires on alt are hot with key off.

 

OK, having 14.9V means you're charging system is working OK (at least partially, but without having an inductive amp clamp, we'll assume it's OK). Have you charged the battery and had it tested? Just to make sure you don't have something simple. Have you disconnected the alternator just to make sure it's not causing a draw?

To do a parasitic load test, you have to measure amperage, not voltage. If you have a quality volt meter, it should have a DC Amp setting. Turn the ignition off, close the doors and make sure everything is off (lights, radio, etc...) Since I don't know what volt meter you have, fabricate a 5A fuse with wires on each end (we'll use this to protect your volt meter), then connect the volt meter, and fused jumper, between the battery negative post and the negative cable in a series circuit. Record how much parasitic load is being shown on the meter. Ideally, it should be less than 50mA (0.050A).

As I was typing this out and making sure I don't forget anything, I decided to just find a video that would cover all the basics. It's kind of long, but watch this video for how to measure parasitic load. He makes most of the points I've already made, but it's sometimes better to see someone else do it. Hope this helps.
I will say that I agree with testing on the Negative side, but not for the reason he gives, because, if you have a high current draw, touching negative to negative still completes the circuit and if the current draw is high enough it could damage your meter or blow the internal fuse, which may be proprietary, not serviceable, or just a pain to deal with if it blows. That's why I suggest making a fused jumper and connect it at the end of one of the meter leads.

 

Thank you for the video. I do have a "leak"(.27a). I had hooked up my meter differently on previous attempts but still got same results. I have 2 fuse panels and removed each fuse separately but the meter never changed. I have bypassed the VATS(jumper in kick panel) because there was no steering column in this car,which I put in from my 82 Z28. I use a manual fuel pump and only use the wire to the gauge from the fuel tank. I run a manual fan on a toggle and a temp gauge. It is my electric trunk lock. With the neg. bat. terminal unhooked, the trunk locked so somewhere I guess there is a ground hooked up wrong

 

Wow, yep over a quarter of an amp will kill a battery pretty quickly. Did you remember to pull the fusible links? Since you've pulled every fuse and still have the 270mA draw then you need to disconnect the unfused items (should be only the starter and the alternator, not forgetting all the fusible links at the starter).

 

Wow, great info here. I have to test my 2000 Ford Ranger for this problem. If I don't start it daily then the battery dies.

 

With all of the bypasses and slicing and dicing on the harness and since I know it is the trunk latch that is draining the battery,for right now I closed the hatch and unhooked the switch. I had to replace the motor when I first got the car and I guess I hooked it back up wrong. I will research the circuit to see where I made the mistake. Thanks for your help

 

Glad to see you found the cause. Glad I could help!

 

Kind of funny that I had left the battery neg. lead off and was doing some "detail" work on the hatch. and when I went to close the hatch it pulled down which is when I realized this was the problem. I believe it is a dedicated circuit so I should be able to find my mistake. I have been looking for this solution for over 2 years and I just now pushed on the hatch after it was shut and I heard a click and lo and behold ....no more "leak". Thanks again for the help.