Trying to do a quick diagnosis on an electrical problem. Basically the car seems to drawing on some very uneven current directly related to engine revs. The higher revs the brigther the lights, etc. At idle all the electrical in the car INCLUDING HEADLIGHTS, wow, flutter and flicker. When I gas it, I usually blow the instrument light fuse. SIZZLE.

This is a project car. And I have no idea how old the ALT is...the belt certainly has seen better days. So, I figure it could be a good start to replace those. Got a new battery ready to go. Any guesses on other causes, or other items I should replace when I am at it. Any outboard regulators, or other items which may effect constant voltage?

Any tips on the ALT swap...seems pretty simple.

Chris Magid
1984 928sx2

 

Sounds like the voltage regulator or alternator...(hope for the Volt reg! $$)

 

Mark,

Thanks for the suggestion. The voltage regulator is part of the ALT...correct? If I put in a new ALT...i would get a new reg?

If not...what volt reg are you talking about?

Still learning the car.

Chris Magid
1984 928s x2

 

A little diagnosis might save you some time and $$$. Buy or borrow a real voltmeter, and connect it to the jump-start post and ground under the hood. Run the car through the duty cycle and see how the voltage varies. Then do the same thing at the battery terminals and compare the readings.

Lots of simple things cause the symptom you describe. Poor connections and poor grounds are a few. Start with these simple things, consider that the battery may not be holding a charge well, etc. The meter will goude you when couple with a little knowledge/experience.

If you see that the voltage gets above 14 with the engine reving, the regulator may be kaput. If you watch the voltage swing between about 12 and about 13.8, your car is fine.

Wally posted an annual electrical maintenance checklist a while ago. I was negligent and didn't save it, but a search might recover it. Or maybe it will get reposted by the author... Many of the wierd problems we face are caused by aging electrics, and following the new annual ritual may be enough to keep you on the road. Finding virgins to sacrifice for the old ceremony is getting tougher than cleaning battery terminals, plus you don't have to deal with the diapers.

If you don't have a voltmeter, Radio Shack has decent-for-car-use digitals starting at less than $30 these days. You'll use it a lot more than you do a spare tire. Good investment.

 

Thanks for the post.

I ran across the list you spoke of. Very helpfull. I plan on doing that maintenance.

I think the car has the original ALT on it...so I think replacing it may be a good idea.

Chris

 

Chris, your signature line varies from post to post so may I suggest (before Randy does &lt;g&gt that you read the thread for new posters. It will answer a lot of questions some relating to your question and it suggests you put your MY (modelYear) and other pertinent and witty flotsam in the sig line so it will stay there -- saves typing. Good luck. <img border="0" alt="[byebye]" title="" src="graemlins/wave.gif" />