| |
The word Tune-up is actually an obsolete and outdated term. Yet many people think their engine
still needs a tune-up. What they actually need is preventive maintenance. Or, if their Check Engine Light is on, what they need is a diagnostic scan to determine what is causing the fault. The same is true if their engine is hard to start, stalls, runs rough, gets poor fuel mileage, doesn't run right, or is experiencing any other kind of driveability or emissions problem.
The only engines that still need a tune-up today are old ones from the 1970s and back with carburetors and distributors. Yet the tune-up myth persists, and may people still think it is some kind of "cure-all" for what ails their engine. To make matters worse, many new car dealers
(particularly import dealers) tell their customers they need a 60,000 mile "major" tune-up (whatever that is). There's no common definition of what exactly a tune-up should include, but most would agree that it involves replacing the spark plugs and performing other adjustments to maintain or restore like-new engine performance. The problem is there is almost nothing that can adjusted or "tuned" under the hood on late model engines with computerized engine controls. Ignition timing is fixed and controlled by the engine computer, as is idle speed and the fuel mixture. Base timing can be checked with a scan tool, but cannot be adjusted on most engines. The same goes for idle speed and various emission functions. A scan tool can reveal if the systems are functioning normally, but in most cases no adjustments are possible because the adjustments are programmed into the computer.
A simple maintenance type tune-up (a new set of plugs) may make an engine easier to start, improve fuel economy, lower emissions
, restore lost pep and power if the spark plugs are worn or fouled. But if the problem is due to something else, a new set of plugs alone won't help. A tune-up under these circumstances would be a waste of time and money. The engine needs to be diagnosed to find out what is wrong.
[ back ]
|
|
