Saturday, February 26, 2011

Return of the Little Red Car


You may remember from our last episode that the Little Red Car had shorted out its electrical system on the freeway and had nearly gotten us all killed. Little did we know that this problem created another, secret, hidden problem that didn’t show up until several weeks had passed. Like high blood pressure, this problem lurked in the background, slowly doing its damage until it reached the point of no return.

Carol was behind the wheel, of course, when the Little Red Car once again stopped working. I don’t remember what I was doing when my cell phone rang, but whatever it was, it didn’t have anything to do with planning a stranded car rescue. My phone is programmed with a special ring that only plays when Carol calls. Since she was calling shortly after she had left the house, I suspected that she was having car trouble. I had her describe the symptoms of the problem to me. From the information she gave me, it sounded like another electrical problem. The lights on the dashboard were working, but the engine had quit running when she stopped at a corner and now the starter would not turn over the engine. The way she described it made it sound as if the battery had gone dead. That seemed strange to me since there had been no evidence of any problem with the charging system on the car. There are no gauges on the car for the electrical system, though, just a light that goes on when the alternator is not generating any power. She hadn’t mentioned any warning lights coming on recently.

Armed with enough information to make a selection of the tools I would likely need, I went down to the workshop and loaded up a tray with my multi-meter, a test light, some electrical tape, a couple of wrenches, a screwdriver, some wire cutters, a pair of Channel-Lock pliers and a pair of Vice Grips. If I couldn’t fix it with that, it would probably have to be towed. Since a battery problem seemed likely, I decided to drive my Baja Bug on the rescue mission. I figured that, if all else failed, I could take the battery out of the Baja Bug and put it in the Little Red Car to get Carol started and back on her way.

When I got to where Carol had stopped, and after saying “hello,” I had her get behind the wheel and try to start the car. It was obvious then, from the way the starter motor reacted, that the battery was dead. I opened up the passenger-side door and, leaning over the front seat, pulled up the bottom of the rear seat to expose the battery. The terminals didn’t look particularly corroded, so I pried off the caps to see if it was low on fluid. It wasn’t just low on fluid, it was nearly dry. It was no wonder that the car wouldn’t start. I removed the battery and set it on the sidewalk alongside the car. I then went to the Baja Bug, removed its battery and installed it into the Little Red Car. The Little Red Car now started and ran just fine. I took the nearly dry battery and installed it into the Baja Bug. It would not start the car, but there seemed to be enough power remaining to run the car, if I could get it started. I left the Little Red Car running, removed its battery and carried it over to the Baja Bug. By placing the two batteries face to face in the Baja Bug and jumping across the terminals from the good battery to the bad one, I was able to get the Baja Bug running. I then left it running, took the good battery back to the Little Red Car and re-installed it.

I sent Carol on her way and I drove the Baja Bug home. Once there, I filled the dry battery up with water. It took quite a lot to fill it up. I then hooked it up to the battery charger and left it to charge while I went back to whatever I had been doing before I was called out for the rescue mission. As I puttered around the house during the day, I thought about all the things that could have caused that battery to go dry that way. The most obvious cause was overcharging. Overcharging will cause the battery fluid to boil off, which seemed to be what had happened. The only way to be certain, though, was to put a volt meter on the alternator of the Little Red Car, and that would have to wait until Carol came home.

I had Carol park the Little Red Car behind the workshop when she got home. I got out my multi-meter, plugged in the leads and set the range for 0-15 volts. Then, I lifted the hood of the car, started up the engine and put the leads from the tester on the appropriate terminals of the alternator. The needle on the tester hit the peg on the right side of the meter and stayed there. I changed the range so that I could see how much voltage the alternator was actually producing. It read over 25 volts, over twice the voltage of the battery. No wonder the battery had boiled dry. At that point, I knew what had happened. When the electrical system had shorted out several weeks before, the short had destroyed the internal voltage regulator on the alternator. Once that happened, the alternator had no regulator at all and was just pouring every volt it could produce right into the battery the entire time the engine was running. The result: a dry battery and a car that won’t start.

Knowing what was wrong, it was a simple matter of replacing the alternator and the car was again running perfectly. I left the new battery in the Little Red Car and kept the boiled one in the Baja Bug, hoping that it hadn’t been ruined. The other day, I discovered that the boiled battery was no longer staying charged, so the next project is replacing the battery in the Baja Bug. At least that will be easy, since I already know what the problem is.