I just recently had a bunch of work done to the engine of my 1993 Honda Accord 10th Anniv. w/172,000 miles... including a complete tune-up, new filters, fluids, seals, gaskets, hoses and the complete timing-belt service done. To finish everything, I decided to have the engine degreased and hosed down to wash off all of the old oil, dirt and grime. The mechanic sprayed the engine a little harder than I thought he should, but he assured me that it wouldn't hurt anything. He didn't use a pressure washer, but he didn't really make an effort to avoid the alt, battery, dist., etc. After he was done, I started the car and it fired right up. Everything seemed fine until about a minute later when the battery light popped on. To shorten this up, the problem is that the alt. seems to be over charging... it's charging at 17-18 volts and triggering the battery light. As soon as I put a load on the electrical system (turn on the AC, use the power windows, etc.) the battery light goes off. As soon as the load decreases, it comes back on again. I can tell everything is getting an extra boost of power. I drove the car home a short distance and parked it... I didn't want to possibly damage anything else.

I was told to let the car sit and let it dry overnight and try it again today... which I did. No luck. I went out to start it and it acted like the battery was really drained... but it started. After about 30 seconds, the battery light came back on. I turned on the AC, and it went off... I drove the car around the neighborhood and the battery light would only start to come on (and kind of flicker) if I went over 2,000 rpms. I came back home and let it idle, turned off the AC and the battery light still remained off. But, as soon as I raised the RPMs, the light came back on again. So, it is still overcharging. After the car idled for a while, I shut it off and restarted it... it started back up normally (no dragging). Not sure why the battery would've been low this morning.

The mechanic wants me to bring the car back on Monday and he said he'll replace the voltage regulator and/or the alternator. I hope that is all it is, and not a deeper electrical system problem. The car does drive fine, otherwise... better than it has in probably a long time!

Will I damage anything by driving the car as it is? According to the volt meter, it's putting out 17.8-18 volts without a load.

Thanks in advance for any help with this matter.

 

Most regulators cap the voltage 14.5V, so you are well outside of spec. Running with that amount of excess voltage can eventually burn out bulbs and other electrical components so you need to get it fixed ASAP.

I had the same problem on my 98 Accord and it was cranking out 16V. I changed the alternator the next day and didn't have any adverse effects.

On your car the volatge regulator is inside the alternator, so he is at least going to have to pull the aternator to fix it.

 

Thanks for the quick reply! I did do a bit of research and learned that over voltage can in fact damage the electrical components... oops. I did have a tail light bulb blow in the back as all of this was going on... now I know why. Well, I haven't driven the car but maybe a total of 8 miles since this all began, so hopefully I haven't taxed anything else too hard. I won't drive it anymore beyond this point.

I think he is going to just replace the alternator tomorrow... (rather than try and fix the existing one) It looks to be the original alternator, now going on 16 years old and 172k miles... so a new/reman. one would probably be best. I'll keep everyone posted.

 

Okay, it just gets worse. I went out to replace the tail light bulb that blew, only to discover that now my car is completely dead. I mean, it has ZERO electrical power. None of the interior lights come on at all, when I turn the key there are no lights on the dash, no clock, radio, absolutely nothing.. just dead silence.

The connections to the battery are secure. The battery doesn't have much reason to be completely dead, but I guess it got fried.

I hope my ignition switch didn't get fried. Here I go getting worried again...

(UPDATE: I hooked the car up to the 07 via jumper cables and it came back to life, so I can rule out ignition switch (whew!). I didn't start it, I just wanted to make sure that the battery was the culprit and not something else. The battery couldn't be any more dead.

 

The excess voltage probably fried one of the cells in your battery.

When my voltage regulator died my battery was 7 years old and in need of replacement anyway so I just went ahead and replaced the battery along with the alternator.

The alternator on my 91 Accord made it to the 206K mark, so you probably had some life left in yours before your mechanic gave it a bath.

Best of luck to you.

 

Yeah, the original Denso alternator is still going strong on my 96 Accord with 230,000+ miles.

The 93's was charging perfectly prior to all of this. I don't know how old the battery is, but it wasn't showing any signs of being weak. It's an Interstate battery.

Thanks for the help so far, I'll def. let you know how it turns out. Not sure yet how I'm going to get the car there tomorrow... I have to work from 7 am to 5 pm.... I'll have to take some time off and see if he'll come to the house and work on it there.

Keeping my fingers crossed that after a new alt. and a new battery (oh, and a new tail light bulb)... she'll be back to normal and I can drive it and get some enjoyment out of all of the work I just had done to it.

I'll keep you posted.

 

Btw, here are a couple of pictures of the car:

 

Well, a new alternator and new battery did the trick... the car is back on the road finally! It drove so smooth and strong that I put it on the Turnpike, set the cruise on 75 and drove for about an hour before turning around and driving back home. Everything seems great, I'd take it on a long road trip without worry.