QUESTION: I have a 1989 Plymouth Acclaim. Lately, I have been having trouble starting the vehicle. Once every couple of weeks during everyday use, when I put the key in, everything is dead. The only thing happening is the "oil" light comes on. The battery is two years old and is connected properly. After failing to start, I will turn on the lights to check for power, turn them off and successfully start the vehicle after a few more dead tries. When the car turns over, the alternator shows the battery is charging and the car will run fine for a number of days before this incident repeats itself. Can you offer any suggestions and guess at what could be the cause?
ANSWER: I have run across this scenario many times over the years and even had it happen to one of my own vehicles. The problem is most likely with the battery.
The clue here is that everything is dead when you go to start the car. The oil light is working, but it takes very little current to operate this light, so it can come on even though everything else doesn't work.
The first items to check are the battery cable connections. You say they are connected properly, but they can look good on the outside and still be corroded on the inside. Remove the cables, taking the ground cable off first and connecting it last to prevent accidentally shorting the positive connection to ground, and clean them up. If you have bolt-on replacement battery cable ends, remove the cable ends from the cable, as sometimes these will corrode where they clamp on but still look good on the outside.
Another place to look are the ground connections. Check the negative battery cable where it connects to the engine and clean and tighten the ground strap between the engine and the body. Sometimes this connection is right at the battery, where it goes from the battery cable clamp to the body.
As I said at the beginning, the problem is most likely the battery. A 12-volt battery is made up of six cells and compartments inside a single exterior case. There are connecting straps between the cells that are spot-welded together to make up a path for the electrical current. If one of these connections is bad, the battery cannot provide any power.
Sometimes, the connection is not completely broken and may provide a little power but not enough to operate headlights or start the engine. However, when you try to use the power, it causes the poor connection to heat up and as it expands, it can temporarily connect again. The battery may work fine for a few times and then the connection becomes poor again. Unfortunately, batteries with this condition can test good, but if tested several times over a few days eventually will fail. If the cable connections are clean and tight, I would replace the battery.
QUESTION: The tire warning light on my Toyota 4Runner has been coming on recently. It was fine all summer but now that fall has arrived, it will come on for a while and then go out. I checked the tire pressures but they seem OK. What could be wrong?
ANSWER: You and a million other people are having the same problem. It doesn't seem to matter what make of vehicle and it is all related to the standards set for low tire pressure warning. As the temperature goes down, so does tire pressure. During the fall and winter, we tend to have larger swings in temperature, so the pressure drops below the limits overnights and comes back up again as you drive and the tire warms up.
The best way to handle this is to inflate your tires to the maximum recommended pressure when they are cold (less than a few blocks of driving). Even doing this, there are times when the warning light will come on. Don't ignore the warning light, for you may really have a low tire, but carry a tire pressure gauge and check them frequently. If the light comes on while you are driving, the tire is likely going flat, but if it is on in the morning after a cold night, it is more likely just the change in pressure due to temperature changes.
Jim Kerr is an experienced mechanic, instructor and member of the Automobile Journalists' Association of Canada.
kerr.jim@sasktel.net
