OK. So, my choke light starts to shine and that wonderful buzzing starts to come on, but only at certain RPMs. It does it at idle sometimes (probably around 500 or so), and then again while driving (maybe 1500). I can understand the light coming on if the RPMs were too low at idle, but why while driving and at only a certain RPM? My alternator seems to be charging the battery ok. I'm not sure how old it is though. All the fuses are still good. This has been going on for a long time, too long to remember if it's a result of an unfriendly mod. The carb could use a rebuild, but the only thing that's been done to the carb is a new choke thermostat. All my mods are in the sig, and I don't think they could've had something to do with it. Any thoughts?

 

Test the alternator, it might be on it's way out(brushes nearly worn out for example). What you describe is why my 82 did for a long time, then the lights would flicker at a constant rate. The light flicker was annoying so I rebuilt the alternator. Works fine now. Also, the whole time it was acting up the battery would stay charged.

 

The buzzing is actually the choke relay. In rare cases, the relay will go bad, and doesn't indicate a problem with the alternator.

99 times out 100 it's the alternator. The choke coil itself actually has NOTHING to with it... all it does is provide a path to ground.

 

Sounds like the Alt is not putting out a clean DC voltage. How old are the alt brushes? They are easy and cheap to replace. Before worn brushes completly fail, the start to "bounce" at certian RPM's.

 

i was able to test my alternator yesterday, and it's putting out the propper voltage. even at the rpms that the buzz starts to go off. so, i guess the problem is with my relay then? how might i fix that? i've read through several searches that the relay is (maybe the green wire) attached to the aldl. but that doesn't really tell me what/where it is? any ideas?

 

The buzzing is caused by one failed diode in the diode trio in the alternator. What ends up happening, is that the alternator is working 2/3 of the time which is enough to keep the batt charged and to make it appear to test good, but not working 1/3 of the time. That condition overstresses the rest of the alt and will shorten its life, besides just annoying the hell out of the driver.

Either replace the diode trio if the rest of the alt is fairly new, or just get a new alt if it's got lots of miles on it.

 

Yes, listen to the guys, it sounds like the alternator, and it usually is, and these guys know a LOT more than me. I would replace the things RB was talking about or get a new alternator.

 

Hey RB. I read your post on Choke light still on, Alternator seems fine, Now What? Very informative. I'm gonna check that out. Thanks man. I appreciate it.

 

replace it.... its definately the diode trio- i had the same thing happen to me in my 86, and the alt tested fine... i picked up a new one, and put it in, and whamo, it problem solved.

 

How are you testing the alternator? If you're just checking the voltage, you're just getting a SMALL part of the story. You really need to test the ouput in AMPs. Just a simple on/off load tester is sufficient in most cases, but a variable, carbon pile load tester is the prefered method, along with the newer capacitance testers. Simply put, if the alt is 1/3 dead, it probably will not be able to maintain 10.5 volts for 15 seconds at the load test rating.

If you don't have the means to test it, go somewhere that does, preferably a shop, not the parts store, parts stores sell parts as their businees, and shops fix car as their business.

 

rebuilt the alternator since it killed my battery. problem solved. although, now I'm getting a new noise. I understand that the clicking noise under the hood is the Mixture Control Solenoid, and I know what the choke buzzer sounds like. This new noise is a lound clicking from inside the car. The choke light is also flashing rapidly. It doesn't do it every time I try to start the engine, even on cold starts.

So, I'm looking at :
1) loud clicking noise (in the inconvenience panel)
2) flashing choke light
3) during some cold starts, but not all cold starts
4) during some hot starts, but not all hot starts

choke relay?

 

What's the alternator output voltage now?

I got that funny clicking noise when mine was putting out too high of charging voltage.

 

You can also check for a bad diode by using the AC scale if you have a bad diode you will have AC output on the alt.

 

13.8-ish

I went back to the shop that rebuilt my alternator for an 'on-vehicle' test, and they said it's doing fine. The clicking only happened once so far today, and not at the time when the voltage was being tested.

 

does it goet louder when you turn on your lights or more constant? and does the sound come from as if it were inside the dash? if yes choke relay.

 

I didn't turn on the lights when it was happening. Yes, it does sound like it's coming from the dash, which leads me to believe it's the choke relay. But, it's not buzzing; just a loud ticking. The Mixture Control Solenoid clicks and stops as it should, but the clicking inside the dash doesn't seem to stop unless I start the engine.

 

I'm glad this post has been brought up again! I'm now having the same problem, but haven't even thought about looking into it. (trans went last week, finished the replacement, the today something developed a BIG trans fluid leak, had a bad day!)

Back on to topic, the first thing I'm gonna do is test the alt for load, and A/C. I've noticed it doesn't seem to keep up as well with everything turned on!

Did you maybe fry the choke relay with the alt being bad? I'll post back if I ever get mine fixed!

 

when I turn on the headlights, the clicking stops. when I turn the lights off, the clicking resumes.

 

I don't know enough about the electrical systems in our cars to be able to answer that, but I'd assume that the choke wouldn't work at all if the relay was fried. I could be wrong.

 

Now that I think of it, if the relay was shorted (the control, or coil side) it wouldn't work, and may blow a fuse, or cause the relay coil to act as a fuse and open up. Basically, I don't think the realy being bad would make it buzz, but something else would have to be causing it. Not 100% sure about this though, I have seen some pretty weird stuff before, in simple circuits such as this one!

 

Replace the choke relay. If it is clicking with 13.8 volts, and doesn't click when the voltage drops (lights on), it's on its way out.

 

You could be right. I guess I'll just have to bite the bullet and pay for the shipping costs to get it here (the price of shipping is equal to the price of the part). The whole thing should cost less than $10, unless a local GM parts counter just happens to have one lying around (doubtful). I haven't had any of the clicking since the last time I mentioned it here. I'll keep you posted.

 

I've never been charged shipping on a part by any GM dealer.

 

I work at Napa and searched for the part through them. They charge shipping. But good call though. I'll go check with GM. Thanks.

 

Now that I think about it, I've never been charged shipping by NAPA or any other parts supplier either.

 

Anybody have the part number for the choke relay? The closest I got was the GM parts guy quoting me $100 for the choke thermostat (that goes on the side of the carb, which I replaced a long time ago, but I don't remember it costing me $100). "I don't know about anything that works with the choke inside the dash," he said.

 

the choke relay is inside the dash under your steering colum on the right side (in my car anyways) and its on this little board which connects acouple relays. it should cost like 5-10 bux i can't remember but it was minimal. i actually saved the box it came with and kept the receipt so your lucky. part number for my 84 trans am for hte choke relay is; 1408 9568

hope this helps


edit: thats the part number on my receipt which i got from GM

 

Carquest. Part no. EC RY144. about $10

 

Thanks for the part numbers guys. It'll probably be a while until I have time to work on the car, but I'll post the results when I get it done.