O.K. so my setup is a B20 in a ED CRX. I am using my D16 alt. currently. After driving for an hour from GF's house, I stop for gas, leaving car idling. When I get back in, I hear five dim beeps and the tach is sitting on the rest. The clock/int. lights are dimming and the tach is all over the place as I am driving... get to my garage, shut off headlights/acc. everything is fine. Tach goes to normal.... Ideas?

 

check the system voltage at ~2000 RPM, if it's below 13.5 or so it's likely a bad alt (should be 13.5-14.5 depending on the vehicle). If cranking voltage is low it's the battery. FYI, it's usually the regulator that goes bad in the alt, not the alternator itself.

 

what ever you do, dont take off the battery terminals while the car is running to test it. take the time to do what the guy said above.

 

Here's my cheap guess..

If you tried what the dude said above and it didn't work...

I'd check the alternator belt to see if it's loose..

And you could also check to make sure that the cables/wires going to the alternator aren't loose..

It sounds as if the alternator isn't putting out enough at idle..

Good luck..

 

take of off and take it to Napa(free testing)
or drive your car to Autozone (free test)
or drive your car to Sears Automotive(testing can be done on altenator) $25

 

Thanks for the replies. So, it is one or the other?