ISC Device Keeps Horses Under Control
Question: We purchased a used 1981 Buick Regal with a six-cylinder engine. When stopped at a signal, the car wants to lunge forward, like a horse chomping at the bit. We have hesitated talking to the dealer, because I’m sure they would blind us with science. What should we do?--S.A.B.
Answer: Automobiles have become so sophisticated electronically that it’s just about impossible to not depend on your mechanic for technical help.
Your Buick has an electronic system called the idle speed control (ISC), which is part of the engine’s emission control system. The ISC will automatically boost the engine speed, if it senses it is dropping below a certain level. And that would create the very condition you describe.
For example, if your engine speed drops below a certain point while you are stopped at a signal, the ISC senses the engine may be ready to stall. So, it quickly tells a computer inside the car to send a signal to a device on the carburetor that automatically gives the engine more gas. That’s about as simple as I can make it for you.
The ISC only comes on when the engine speed drops below a certain point. Your problem may be that the idle speed is set incorrectly. A minimum or base idle speed must be set with the ISC system disconnected. If the base idle speed is set too low or too high, the ISC will come on when it isn’t supposed to.
I suggest you take it to a reputable dealer and have the problem fixed. An improperly set ISC is an irritation that you shouldn’t ignore.
Q: We have a 1983 Toyota Tercel with a five-speed manual transmission. At 30,000 miles, a new clutch was installed, and 9,000 miles later it needed another new clutch. We have been driving stick shifts for years and never had this happen before. My wife uses the car for short trips, never going more than 40 miles per hour. Could that have any effect?--B.P.
A: A clutch failure after 30,000 is premature unless you are really hard on it. Brakes and clutches are two things that most manufacturers are unwilling to warrant for very long, because they can fail prematurely if they are not used properly.
Assuming that you are experienced with manual transmissions, you may have gotten a defective clutch on the first go around. The second clutch had to be improperly installed or substandard to fail after 9,000 miles.
The questions you need to answer for yourself are whether the clutch was repaired with original-equipment parts, whether the mechanic was properly trained and precisely what caused the failure.
Short trips do cause more wear on a clutch than a lot of highway driving, but it should still last longer than 30,000 miles.
Q: We recently bought a new 1986 Olds Delta 88. It used a quart of oil in the first thousand miles. Is this normal? We were told it may continue to do so and the engine will fail after 50,000 miles.--N.M.
A: A lot of new cars will do significantly better than that on oil consumption right off the bat, but it’s not uncommon for a Delta 88 to lose a quart of oil in the first thousand miles.
The oil consumption should settle down to no more than a quart every 2,000 miles after you have 4,000 miles on the car’s odometer. If the engine rings don’t seat by then, they’ll never seat properly.
As for premature engine failure, you don’t have much to worry about. Some cars use more oil than others, and their engines keep chugging just as long as others.
