Mixed Deck — All NAPA Topics Flashcards

A vehicle with an automatic transmission is brought into the shop with the complaint of delayed engagement and the engine RPM flaring up during shifts. The technician confirms the fluid level is correct and the fluid is not burnt. Which of the following is the MOST likely cause of these symptoms?

Answer: Worn clutch packs or bands

When clutch packs or bands inside an automatic transmission are worn, they cannot create the necessary friction to engage gears properly. This results in the engine speed increasing without a corresponding increase in vehicle speed (flaring) and a noticeable delay before the gear engages.

After a turn, a vehicle keeps pulling in the direction of the last turn. This 'memory steer' is most likely caused by:

Answer: A binding upper strut mount bearing

A binding strut bearing or tight joint keeps the wheels from returning to center after a turn.

A toe-out-on-turns (turning radius) reading is out of specification on one side. What is the most likely cause?

Answer: A bent steering arm

Toe-out on turns depends on steering arm geometry, so a bent steering arm throws it out of spec.

When should the parking brake be adjusted during a rear drum brake job?

Answer: After the service brake shoes have been properly adjusted

Adjusting the parking brake before the shoes are set can hold the shoes off the anchor and cause dragging.

When testing a coil-on-plug ignition coil, the most effective way to confirm a misfire follows the coil is what?

Answer: Swap the coil to another cylinder and see if the misfire moves

If the misfire code moves to the new cylinder with the coil, the coil is confirmed faulty.

On a short-long arm (SLA) suspension with the coil spring on the lower control arm, which ball joint is load-carrying?

Answer: The lower ball joint

The ball joint on the arm that supports the spring carries the vehicle's weight.

A technician is performing a wheel alignment and finds the caster angle is significantly more positive on the left front wheel than on the right. What is the MOST likely effect this will have on the vehicle's handling?

Answer: The vehicle will pull to the left.

Caster is the forward or rearward tilt of the steering axis. A more positive caster angle provides greater straight-line stability. When caster angles are unequal side-to-side, the vehicle will pull toward the side with the LEAST amount of positive caster. In this case, with the left side being more positive, the vehicle will pull to the right.

A drive-by-wire throttle body is cleaned and the engine now idles erratically. What step is often required?

Answer: Perform a throttle body idle relearn procedure

Many electronic throttle systems need an idle or throttle relearn after cleaning so the PCM learns the new airflow at closed throttle.

A DMM set to ohms reads 'OL' when connected across a wire. What does this indicate?

Answer: An open circuit

OL means the resistance is beyond the meter's range, which indicates an open circuit.

A vehicle makes a clunk when shifting from drive to reverse, and the driveshaft shows movement at the U-joint. What is the most likely cause?

Answer: Worn U-joint needle bearings

Worn U-joint bearings create play that clunks when driveline torque changes direction.

A hydraulic clutch pedal slowly sinks to the floor when held down at a stop, and the clutch begins to drag. What is the most likely cause?

Answer: Internal leak past the master cylinder primary seal

Fluid bypassing the master cylinder seal lets pressure bleed off, so the pedal sinks and the clutch stops releasing fully.

On many star-wheel self-adjusting duo-servo drum brakes, when does the adjuster normally operate?

Answer: When the brakes are applied while the vehicle moves in reverse

Most duo-servo self-adjusters work when the brakes are applied in reverse, as the secondary shoe moves the adjuster lever.

With the engine running and loads moderate, what charging system voltage range is normal for most vehicles?

Answer: 13.5 to 14.5 volts

Regulators typically hold system voltage around 13.5-14.5 V to charge the battery without overcharging it.

A stator one-way clutch that is seized (locked in both directions) typically causes what symptom?

Answer: Poor high-speed performance and fluid overheating

A locked stator interferes with fluid flow during the coupling phase, which limits top speed and creates heat.

Which EVAP condition is most likely to cause a rich condition and rough idle right after refueling?

Answer: Purge solenoid stuck open

A purge valve stuck open draws heavy fuel vapor from the freshly loaded canister into the intake at idle.

Most engine coolant temperature sensors are NTC thermistors. As coolant temperature rises, the sensor's resistance:

Answer: Decreases

Negative temperature coefficient means resistance falls as temperature rises.

Which tool is commonly used to measure crankshaft bearing oil clearance during engine assembly?

Answer: Plastigage

Plastigage is crushed between bearing and journal, and its width indicates clearance.

What is the most common cause of in-tank electric fuel pump failure?

Answer: Habitually running the fuel tank at very low levels, reducing pump cooling

In-tank pumps are cooled by the surrounding fuel; consistently running low deprives the pump of cooling and causes it to overheat and fail prematurely.

A vehicle pulls to the left, and the alignment readings show caster is uneven side to side. Which condition would cause this pull?

Answer: Less positive caster on the left wheel

A vehicle tends to pull toward the side with the least positive caster.

A customer says the left turn signal flashes much faster than normal. What is the most likely cause?

Answer: A burned-out turn signal bulb on the left side

Reduced current from a burned-out bulb makes a thermal flasher cycle faster.