I picked up my new 65 chevelle today. The guy said he noticed the volt gauge was fluxuating from 12-14 volts. He said normaly it stays at 14 volts. It has a 1 wire alt. from unknown vendor. Well I started to drive down the highway and the gauge was reading 14 like he said it does. Then I had to stop and put rain x on the windows, no wiper motor. Once I got back on the freeway I noticed it was sitting about 12 volts, then 11, then 10 and stayed around 10-10.5 volts. I`ve never delt with 1 wire altinators before so where should I look for problems? The battery is in the trunk if it makes a difference. It seems to be charging just not as good as it should. I also noticed the temp was getting a little high so I though the altinator belt might be loose but I checked it when I got home and it`s tight but I guess it could be slipping. Anybody have a suggestion before I go buy another altinator? Can I take it to kragen and have it tested like a regular altinator? Thanks guys.

Your alternator just took a dump, and no, it is not charging. When it was at 12 the battery was charged, the voltage kept dropping because you were running just off the battery. Check all connections to make sure they were tight, if they are, have the alternator tested.

Thanks for the reply. I`ve never delt with these 1 wire altinators. Can I take it to kragen or somewhere and have it tested like a regular altinator? The last time I have a bad altinator the volts droped down realy low,well below 10. I`m not familyar with the way these 1 wires work so I thought it might just be charging really low. I guess not. Electrical isn`t my strong point and trying to finure out someone else`s work makes it that much more harder. Thanks again.

Yes, they should be able to test it (although sometimes it depends on the operator). You can get one wire alternators from Summit or Jegs. Most auto part stores sell only original type, 3 wire alternators. If you replace it with a 3 wire use a internally regulated one. For wiring go here
http://www.chevelles.com/forums/showthread.php?t=92761
and here
http://www.chevelles.com/techref/ftecref14.html

If the alternator is bad, I would suggest going to the 3 wire internally regulated one. They are suppossed to be better. Mad Enterprises has a good article showing the difference.

Good Luck

Jonathan

Thanks guys. I just ordered a 1 wire unit from summitt. It`s a 100 amp one. i hope it solves my problem. I`m probably going to rewire the car this winter so hopefully it will make it through the summer. thanks again.

Just don't freak out when you install the new one. You have to rev the engine to about 2k before the alt excites and starts charging. That's normal operation.

Just don't freak out when you install the new one. You have to rev the engine to about 2k before the alt excites and starts charging. That's normal operation.

yeah a guy at work was just telling me about that. Does that mean it won`t ever charge below 2k rpm or is that just a initial thing? Thanks.

yeah a guy at work was just telling me about that. Does that mean it won`t ever charge below 2k rpm or is that just a initial thing? Thanks.

I will be installing a single wire alt. soon too and wondered the same thing. Wondering if it will work if you just get on the road and naturally go above 2k rpm street driving.

Well I don`t know whats going on now. I get home, fire it up and it reads 14 volts. I shut it off, go do something real quick, come back and fire it up again and it only reads 12 volts. I reved it alittle, maybe 1,500 rpms and it`s back up to 14 volts. What could be causing that? It reads 14 volts at idle most of the time so I don`t know if the altinator is bad now or not. I did`nt have time to check it tonight but I`ll check it tomorrow.

Well I don`t know whats going on now. I get home, fire it up and it reads 14 volts. I shut it off, go do something real quick, come back and fire it up again and it only reads 12 volts. I revved it alittle, maybe 1,500 rpms and it`s back up to 14 volts. What could be causing that? It reads 14 volts at idle most of the time so I don`t know if the alternator is bad now or not. I didn't have time to check it tonight but I`ll check it tomorrow.
Read d1_bradley's post again, this is normal operation of a 1 wire alternator. 1 wire alternators need about 4k or so alternator shaft rpm to start the alternator. In engine rpm this can very, depending on crank to alternator pulley ratio. Now in your first post you did mention going down the highway and having only 12 volts. Unless the car has very tall tires and a short gear ratio (ie 2.73, 2.56 ect...) , and you were really babying it, it should have easily had more than enough rpm to start the alternator. Now once the alternator starts charging it should stay charging (14 volts) even at idle, unless the alternator is to small and you have a lot of high draw items (ie electric fans ect...) My advice now would be when the car is first started, rev the engine some (2k+) to start the alternator. If it goes to 14 volts and stays there, then there is no problem. If it does not, then there is a problem. Some people find revving the engine to start the alternator annoying, with a 3 wire alternator you don't have to as it is started with battery power. Hope this helps.

I will be installing a single wire alt. soon too and wondered the same thing. Wondering if it will work if you just get on the road and naturally go above 2k rpm street driving.
The engine, once it is first started has to be revved to start the alternator. Once it starts it should stay started even at idle speed. Some people find revving the engine to start the alternator annoying, with a 3 wire alternator you don't have to as it is started with battery power.

Undee, thanks for the info. It`s very helpfull. The car does have electric fans. The tires are 275/6-/15 and I think it has 3.55 gears. My wife was pacing me at 70mpr and I was doing 3k rpms. It seems to run fine, sometimes the volts are high and sometimes not. It did go to 14 volts this morning after I reved it but it drpoped back down to 12 going down the freeway. I got a new altinator coming so I`ll swap it out but I`ll have to find a better way of charging the battery. Thanks again.

You should be able to find the wire from the alternator light and connect it to the 1-wire alternator. I believe it's terminal 1 on the alternator connector when you pull out the rubber plug. This way, you don't have to rev it anymore and the light will tell you if the alternator has engaged and is at least trying to charge.

Peter

You should be able to find the wire from the alternator light and connect it to the 1-wire alternator. I believe it's terminal 1 on the alternator connector when you pull out the rubber plug. This way, you don't have to rev it anymore and the light will tell you if the alternator has engaged and is at least trying to charge.

Peter

What light are you refering to? Do you mean the alt. light? the car has factory gauges that are not functional but it has Autometer sport comp oil,water, and volts. It would be nice if I could find a better way to make this 1 wire alt work so if you can tell me how to hook it up, that would be great. Thanks.

It would be nice if I could find a better way to make this 1 wire alt work so if you can tell me how to hook it up, that would be great. Thanks.
For a 100amp alternator you really should upgrade the alternator BAT wire to a 8g, as the factory 10g wasn't made to handle a high amp alternator. Just so you know, some 1 wire alternators can only be wired 1 wire only, you may not be able to wire it as a 3 wire later. Some of the ones Summit sells comes to mind. After you install your new alternator and if you have any voltage problems post back.

Thanks Undee. I saw the wire kits for high amp altinators. I guess I should get one. When I rewire the car, if I go back to the regular wiring, I`ll go back to the correct altinator as well. UPS tried to deliver it yesterday buy nobody was there so they will try again on Monday. I think I`m going to order a wire kit and install everything together. I will post back and let everyone know how it goes. Thanks again.

The wire is still there even if the car doesn't have the light. It should be brown and would have run to the regulator plug (flat 4-wire) on the drivers side of the rad support.

Peter

Check out my website for how to wire up the SI and CS style alts.

Joe

just wanted to update everyone. I installed the new 100 amp 1 wire alt. from Summit yesterday and it`s charging great now. The one I took off was a 100 amp also and it loks identical to the new one. anyway, it`s working great now. thanks for all of the info.