My car is a 1984, with 117,000 miles

Hi I have read some of your postings in the forum, and last week the voltage of my battery when from good to my car dying at the gas station. The voltage was really low, so I recharge the battery to full charge, and it happen again. I figure that maybe the alternator was the cause so I made the change from CS-130 to it's big brother, the CS-144. (file://localhost/Users/mr/Desktop/C4%20Corvette/alternator%20convertion.html). I fully charge the battery when I installed the new alternator, and same thing happen. Today I got a new battery and still the volts aren't going over 11.7 Volts. The guy at O'reilly told me that maybe the alternator regulator need it to be change. Where is the regulator located at? and is this sound like a regulator or something else. The fuses are OK. Anything else that I can check. Thank you for all your help!!

 

The regulator is part of the alternator, so you've already changed it.

You can find the wiring diagram for your car further down...

Get your voltmeter out and start checking.

 

A lot of places, including o'reilly, use refurbished alternators. I have seen my share of bad refurbs. They should have an alternator test bench there. have them test it to make sure they gave you a good one.

 

No They did not test the alternator, and I bought the alternator at Advance auto parts, I don't know if it makes a difference.

Mr Schumacher what do I have to test with the voltemeter, and in the diagram I don't see anything that goes to the alternator. Thank you!

 

My bad. That link didn't work correctly. Start by verifying that you have 12 volts where ever it says "hot". Check on both sides of the fusible links.

 

first, verify at the alternator that the big battery lead on the alternator has 12 (battery) volts. If the volts can't get to the battery, it won't charge it.
Check all the fusible links. hunt them down and use push pins connected to the voltmeter with the negative voltmeter lead clipped to a known ground to test them.
If the voltmeter on the dash says it has 11.7 volts, then usually system resistance indicates that you actually have .1 to .5 volts in the battery more than that.
Check that the wire in the connector on the alternator connector harness that is supposed to be battery reference voltage actually reads the battery voltage.

 

Thank you guys! I really appreciate you help I'll try it this coming week, and I will get back with you. Thank you again!

 

Dammit, that still didn't work correctly.

Hopefully I have it right This time

 

My understanding is that when you upgrade to the CS-144 an inline resistor is supposed to be installed on the exciter wire. Also, a test to measure the resisitance of the exciter wire between the battery cable and the exciter wire at the alternator determines if you need the resistor installed inline. This is done with the positive battery cable disconnected and the ignition switch in the on position.

I did the same upgrade to my '85. I had low voltage and installed the CS-144. The resistance test determined I needed the resistor but what is interesting is that when I performed the test the resistance was swinging with high resistance. The meter was going up and down. I discovered that my high mileage '85 with 175,000 miles had a bad or worn out ignition switch. The exciter wire gets it's voltage through the ignition switch. I replaced the ignition switch at the bottom of the steering column and after installing the new alternator got a solid 14+ volts. I'm pretty sure the bad ignition switch was the reason for the low voltage at low rpms with the old alternator. I couldn't check it with the old alternator and the new ignition switch because the original alternator was bad. It had some loose parts rattling around inside. I would suggest checking the resistance between the battery cable and the exciter wire. The exciter wire is the dark colored wire, supposted to be brown, that is on the connector that plugs on top of the alternator. Not the red wires. I recall you're supposed to have about 30 ohms or more to use the CS-144. Any less and you need the inline resisitor. You should see less than 30 ohms and more like 10 ohms when you do this test.

Art

 

Well I did check for 12 volts in both sides of the fusible links and it was the same all around 12.5 volts. The same in the battery and alternator. Before I tested everything I got the battery fully charged and after running the car for about 5 minutes the charge drop again to about 11.7 inside meter and coupeyguy you were right the voltage outside is about .5 more.
I also check the resistance between the exciter wire and positive cable while the ignition is on and is 500 omhz. As far as I know some people needed the inline resistor and some don't. Do you think that I still need an inline resistor? Also I got another alternator coming today from advance, and this time I'm going to have it bench test to make sure. I'm going to installed tomorrow, and let you guys know.

I live in Lawrenceville Ga. do any of you guys know of a good corvette mechanic, in case if it doesn't work. Last time I took my car to a mechanic he didn't call me and when I got there to pick up the car he charge me $800 with out my concent, so I'm affraid to take just to anyone.

Thank you!

 

Its looking like a defective alternator.

You did put the belt back on, right?

(just kidding)

Keep us posted, okay?

 

Make sure the B+ from the alternator (stud) is going to the starter. An open there will run at 11.7 and loosing power the whole time. I had a problem with the connector right at the stud. Fixed that and darn there was my 13.8 to 14.2. It's a cheap check and fix. Good luck.
Woody

 

If the B+ stud is the single red wire going to the starter right! I check the voltage there and it was going to the starter and still was the same as the one in the battery. I guess I'm still not clear abouth open part, I'm thinking that if there was an interrumption in the cable to the starter there should be no voltage at the end right. But it sounds like the same problem because the max vol. in the car indicator is 11.7. I guess I'm not clear about the open part can you please elavorate on that. Thank you I appriciate all of your help guys!

And no the belt has been off all this time (Just kidding Thank you!)

 

I vote for a bad alternator. Ive had a few that had to be returned. Second , a bad connection at the junction block.....

 

I got my new alternator today. I got it bench test it right there and it was about 15 volts. I put it on, and guess what still the same problem, (I did fully charge the battery before installing it). I'm going to check the cables again to make sure. Thank you!

 

Get your voltmeter out and, with the engine off and everything hooked up, check the big wire at the alternator. It should read battery voltage. If it reads zero the fusible link is blown.

If it passes that test, remove the plug in connector from the alternator and turn the key to the "run" position. There should be battery voltage at both pins in the connector. (I believe you model has two, some have three)

If both of these wires also have battery voltage, you need a new dilithium crystal.

Seriously, an alternator is a pretty basic device. If it is working, and yours tests good, then all it needs are those connections to be correct and it has to charge. So you have to be missing one of those lines.

 

You must use the adaptor when changing from an SI to a CS alternator. Here's the tech tip I did a few years ago.

 

The CS144 alternator is a direct replacement for your CS-130, no resistor or adapter is required. A better test of the fusible link in the large output wire of the alternator is to disconnect the ground cable from the battery and use your ohmeter and measure the resistance between the output terminal on the alternator to the positive terminal on the battery. It should be very low resistance, the same resistance as touching the ohmeter probes together. Any higher resistance than this and you likely have a burned out fusible link in the alternator output wire. With the battery cables connected, unplug the alternator and measure the voltage on the two red wires of the plug, both wires must have 12v (battery voltage) on them. If they don't have 12v on them, then their fusible links are blown. You can also measure the resistance from each red wire (unplugged) to the positive terminal of the battery (battery can be left connected). Both red wires should read the same as touching the ohmeter probes together. Check the 3 amp coolant fan fuse in your fuse block with your ohmeter. Alternator unplugged and ignition in run, measure the voltage on the blue wire on the alternator plug, it should be 12v (battery voltage). The brown wire on the alternator plug goes to the battery symbol light on your dash, it should also have 12v on it with the ign sw in run. Somewhere in these 5 wires you should find out where your problem is.

 

I check the resistance between the exciter wire and the battery cable so I know that I don't need the resistor, but I did buy the adaptor for the electrical connection online for $25 I think wouldn't be able to connect the wire with out it. But I will check the cables again.

Now as far as the dilithium crystals I used the last one in my motorcycle, but if Mr. Schumacher is willing to give me one I would appreciate that.

 

CS130 isn't factory on an '84.

Although this might not be the problem.