Microchip May ‘Chuggle’ Away the Ping
Question: I’m having a pinging problem on my 1981 Buick Regal with a 3.8-liter engine. The engine pings and overheats at strange times, such as on a level road at steady speed. I’ve flushed the cooling system, installed a new PCV valve, checked the timing, installed new spark plugs and also checked manifold vacuum. The problem persists. Do you have a suggestion?--R.L.
Answer: The car probably has a rather arcane problem with its exhaust gas recirculation (EGR) system, which was described in a 1982 service bulletin issued by Buick. The EGR system may be going off when it isn’t supposed to.
The EGR system is designed to inject small quantities of exhaust gas back into the engine, which reduces peak combustion temperatures and cuts down the formation of the pollutant nitrous oxide. If the supply of exhaust gas is cut off, the temperature in the engine rises and the combustion of fuel becomes less controlled, resulting in ping.
Fixing the problem involves the installation of a new microprocessor chip, called a “chuggle and detonation kit.” It may be covered by a manufacturer’s extended warranty, if you haggle with the dealer. Otherwise, the repair is about $80.
Q: I have a Toyota Camry with an air conditioner that began blowing hot air last June. It is not consistent, though. It might operate properly for a few days and then malfunction for a few days. Repeated returns to the dealer have been to no avail; I still don’t have it fixed.--B.K.
A: It’s unfortunate that none of the dealership mechanics could fix it, because they should have known exactly what the problem was. A service bulletin issued by Toyota describes your problem and a remedy.
The problem is with an electrical connection at a sensor on the compressor. The sensor is designed to make sure the compressor and the engine speed are the same, to prevent damage to the compressor. If they differ, the sensor instructs a microprocessor to shut down the air-conditioning system.
The repair is fairly simple. A new “pigtail,” a particular kind of wire, is installed at the sensor. It should cost $50 or less.
Q: I have a 1978 Olds Cutlass Supreme that has a cooling problem. When the car is idling, it heats up from 190 degrees to 240 degrees, and that’s without the air conditioning on. When I had the cooling system flushed, a mechanic said the radiator fan was not drawing enough air. He demonstrated that by holding a piece of cardboard in the path of the fan, which stopped it. He suggested I replace the fan with an electric or a “flex-fan.” Is this advisable?--M.C.E.
A: The mechanic’s demonstration was pretty nifty, but it did not prove that you have a defective or ineffective fan. The viscose clutch on your fan would stop with such a blockage even if it were brand new.
I would want to make sure all the elements of my cooling system were working properly before I began modifying the design with a new type of fan.
An overheating condition that occurs at idle often does not indicate a blockage in the radiator, so your flushing the system probably didn’t help much. A blockage that restricts the flow of coolant usually causes overheating at high speeds, when the engine is producing the most heat.
It may be that the viscose clutch on your fan is defective. Over time, a bimetallic element, which controls when the fan comes on, can deteriorate with age. Possibly, replacing the original equipment fan would help.
Finally, your mechanic should also make sure that the thermostat and water pump are operating correctly.
Ralph Vartabedian cannot answer mail personally but will respond in this column to automotive questions of general interest. Do not telephone. Write to Your Wheels, You section, The Times, Times Mirror Square, Los Angeles 90053.
