Glossary of Terms Used In Pinpoint Tests
AccelerationLight
Part throttle increase in speed such as 0-97 kph (0-60 mph) in approximately 30 seconds.
Heavy
One-half to full throttle increase in speed such as 0-97 kph (0-60 mph) in approximately 20 seconds.
WOT
Wide open throttle.
Ambient Temperature
Surrounding or prevailing temperature. Normally, the temperature in the service area or outdoors, depending on where testing is taking place.
Articulation
Vertical movement of the transaxle relative to the frame of the vehicle to which it is attached.
Belt Chirp
An intermittent noise usually at idle caused by belt misalignment.
Belt Squeal
A continuous high4requency noise caused by a frozen accessory or insufficient tension.
Boom
A low-frequency, sometimes cycling, rhythmic noise often accompanied by a sensation of pressure on the ear drums.
Bound Up
Refers to a stressed, rubber-mounted component that transmits any Noise, Vibration and Harshness (NVH) which would normally be absorbed by the mount. Refer to Neutralize.
Brakes Applied
When vehicle is stationary and the service brakes are applied with enough force to hold vehicle against movement with transaxle in gear or drive.
Camber
Angle formed between front wheel spindle axis and horizontal as viewed from in front of the vehicle. Camber is positive when the wheel tops are farther apart than the bottoms.
Caster
Angle formed between spindle centerline axis and a vertical axis as viewed from the side of vehicle. Caster is considered positive when top of the spindle axis is behind vertical axis.
Chuckle
Refers to the noise that occurs on the coast driving phase; usually caused by excessive clearance due to differential gear wear or by a damaged tooth on the coast side of the final drive ring gear or the final drive sun gear.
Clunk
Clunk may be a metallic noise heard when the automatic transaxle is engaged in REVERSE or DRIVE or it may occur when throttle is applied or released. It is caused by backlash somewhere in the driveline; it is felt or heard in the transaxle or halfshafts.
Coast/Deceleration
Engine/transaxle engaged, foot off accelerator pedal.
Coast/Neutral Coast
Engine/transaxle taken out of gear by placing transaxle selector in NEUTRAL or by depressing clutch for manual transaxles.
CPS
Cycles Per Second (Hz).
Cruise
Steady highway speed; neither accelerating nor decelerating; even pressure on accelerator pedal on level ground.
Deceleration
Slowing of vehicle by releasing foot from accelerator pedal at cruise and allowing engine to slow vehicle without application of brakes.
Drivetrain
Includes all power transmitting components from the rear of the engine to the wheel, including clutch/torque converter and transaxle halfshafts.
Engine Imbalance
Some component in the engine which is normally smoothly balanced now causing a perceptible vibration in the vehicle.
Engine Misfire
One or more cylinders in the engine fails to fire at the proper time.
Engine Runup Test
Operation of engine through normal rpm range while vehicle is sitting still.This test is used for engine and accessory vibration check.
Float
A cruising drive mode in which throttle setting matches engine speed to road speed, between cruise and coast.
Gravelly Feel
A grinding or growl in a component, similar to the feel experienced while driving on gravel.
Harshness
A harder than usual behavior of a component, like riding a vehicle with overinflated tires usually associated with road impacts.
Heavy Brake Applies
Firm brake pedal pressure pending lock-up.
Hz
Hertz (cycles per second).
Imbalance
Out of balance; more weight on one side of a rotating component causing shake or vibration.
Inboard
Toward the centerline of the vehicle. Opposite of Outboard.
Isolate
Separate from the influence of other components.
Light Brake Applies
Enough brake pedal pressure to just begin to slow vehicle while off the accelerator.
Neutralize (Normalize)
To return to unstressed position. Used to describe mounts. Refer to Bound Up.
NVH
Noise, vibration and harshness.
Outboard
Toward the outside of the vehicle, rather than toward the centerline. Opposite of Inboard.
Pumping Feel
A very slow vibration that results in a movement of vehicle components similar to pumping the service brakes slightly.
Radial/Lateral
Radial is in the plane of rotation, while lateral is at 90 degrees to the fore-and-aft plane on the vehicle.
Road Test
Operation of vehicle under conditions designed to recreate the condition.
Runout
Out of round or wobble.
Shake
Low frequency vibration; usually results in visual movement of components.
Tip-In Moan
A light moaning noise is heard when the vehicle is lightly accelerated between 40-64 kph (25-40 mph).
TIR
Total indicator runout.
Tire Deflection
Bending of the body of the tire during rotation.
Tire Force Vibration
Tire vibration caused by variations in the construction of the tire, resulting in a vibration when the tire rotates against the pavement. This condition may be present on perfectly round and perfectly balanced tires because of variations in the inner tire construction.
Tires-Flat Spots
Commonly caused by letting vehicle stand when tires are warm. Can be corrected by operating vehicle until tires are warm. This concern is more likely to occur with N, V and Z-speed rated tires.
Two-Plane Balance
Radial and lateral balance.
Vibration
Regular movement of a component that results in a sound or feel of movement.
Typical vibration frequencies, measured in cycles per second (Hz), are:
1. engine accessories (up to 200 Hz).
2. engine (50 Hz) - firing (200 Hz).
3. wheel and tires (13 Hz).
4. wheel bearing (6 Hz).
5. tip-in moan (120 Hz).