What is a Tune Up?

By todays standards, a tune up is not like a tune up in the good old days. You may remember back to a time when dad or grandpa worked on the family car in the drive way. With many trips to the auto parts store and two six packs of liquid helper the car would run again.

On a modern O.B.D. 2 car, a tune up it is very different from pre 1999 cars.

O.B.D. 2 started back in 1995, but only on some cars and light trucks. By 1999 every car and light truck on the road had O.B.D. 2 computers running the engine and transmission systems. Many government mandates reshaped how engines and transmission systems are managed. Fuel economy and emissions standards became tighter. So car makers had to make changes.

From 1980 to 1999 many american cars used O.B.D. 1 computers. The O.B.D. 1 computer was slow and prone to odd issues. Each car maker had its own system with its own set of codes and short comings.

As fast as home computers changed, the computers used in cars changed, becoming faster and more capable. Some manufactures used old school ways with new electronics and it made a mess of everything under the hood. So many hoses, wires, valves and sensors it just made your head spin.

Imports had electronic systems back in to the 70’s, but no two makes of car ran the same style of system and they changed every 2 to 3 years. Many import cars used parts that did the same things that O.B.D. 1 parts did, but no one used a uniform standard. It was a big mess until O.B.D. 2.

Back in the old days of points, plugs and wires.

Prior to electronic ignition systems, every engine used a set of points to trigger the ignition system. The points system was a mechanical on off switch for the ignition system. Every 6 months or so the parts would wear out and need replacement or a tune up. On the older cars you did not have a computer to give you a code. You had to find the fault by doing tests on all the parts that ran the engine.

Repairing the older cars required the mechanic to hook up a big engine scope to the engine. Getting good data from the engine during its operation was critical to a fast diagnosis. This was the heart of no code driveability. You had to know how every part worked and how wear effected the way the engine ran or how the transmission would respond. I do not miss the old cars, but I still have some vintage rides stop in for service.

Todays version of a tune up may consist of pulling codes and replacing some broken parts, but for the most part a modern car has nothing to tune up. A computer running a program sets the idle speed and timing to maximise fuel economy and engine performance, its pre-set, nothing to adjust. Service intervals are longer and wearing parts like spark plugs last longer.  The Distributer, distributer cap, rotor, ignition wires and coil has been replaced with an ignition coil on plug ignition systems. Todays engine bay looks simple in comparison to a 80’s car. So what is a tune up? It’s about replacing the worn parts and making the car happy.

It’s all good under the hood. Anthony Xavier ASE Master Technician

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