Hey all, I hope someone can help figure this out. I have a 2003 CR-V LX in Illinois, the headlights, taillights, instrument panel, and interior lights all pulse in time with each other while the engine is running. The pulses fluctuate sometimes going a couple a second, sometimes stretching out for a second, before getting faster again. The radio lights do not pulse with the rest, I think because it has it's own power adapter. The engine rpm at idle will also rise and fall by sound slightly, doesn't usually show in cluster. It has gone away for a day or two intermittently, and it has also set the alternator light to flicker a few times then everything gets really dim and the car dies. It will start up again after sitting a bit, or rather I didn't try to restart right away, and after this happened twice in the past 2 weeks I stopped driving the car. I have replaced the battery 3 months ago, the alternator 6 months, and the eld last monday. I replaced all of this because of this flickering or pulsing problem. All of the under the dash fuses look fine, so I'm about to start hunting grounds, does anyone have an idea what else I could be looking for?

 

What voltage does the alternator put out and is it stable? The radio is on the acc line but has stuff inside to regulate voltage. Check at the battery and then if you have an scantool from the connector.

Hopefully you don't have a **** alternator. My original was over-charging and burnt batteries, the replacement stopped charging completely and the 3rd one finally worked well.

 

I had a battery/charging system tester hooked up to the battery and when the car was running the voltage bounced around in the 14.1 to 14.7 range constantly. It did that with the old alternator and the new one, that was also why I replaced the eld because it is supposed to help control the alternator. The voltage is steady when the engine is not running. The alternator is a TYC, and the car ran the same with both.

 

Have you checked the condition of both major grounds off the battery?

 

14.7 is bad. That's where the battery cooking and dash lighting came from on my car. I think the highest I see now is like 14.4. At least its not putting that out all the time or you'd smell the battery.

 

@Occidentalis, Yes I have checked both grounds and cleaned them with parts cleaner and steel wool, as well as the wire by the power steering. I got a cd copy of the shop manual this week, and I'm tracing the grounds in the front, but without pics its slow going.

@h0twheels, Yeah I've heard that anything over 15 damages the battery and that it should be steady and somewhere between 14.2 and 14.5 for a 12v system.

So basically, what can cause the voltage to fluctuate when the engine is running but not when it is off, and probably isn't the alternator or the eld because both have been changed and the problem has remained the same?

 

Check the belt/pulley system itself too. Make sure the tensioner works and that nothing is wobbling. That will definitely make charging bounce. When the car is off, the alternator isn't moving. ELD regulates between 14.2-14.5 but they shouldn't change super quickly. When your battery is full and there isn't a lot of load it can shut the alt down too.