Ignition Systems Questions and Answers

Answer: C

Deposits provide an easier path so the voltage needed is low, and the remaining energy sustains a long burn. It is the opposite pattern to a worn plug, which is precisely what makes the measurement useful. Checking which component actually carries the load settles most questions of this kind at once. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. Naming what changes and what stays the same is the reliable route through questions of this shape.

Answer: D

Thirty thousand volts gives a severe shock that can cause a fall or a startle injury, and it is dangerous to anyone with a pacemaker. Insulated tools and pliers for removing leads are the practical answer. Tracing the requirement back to the physical constraint that produces it makes the answer follow. The order in which the effects act is what decides the outcome, so it is worth establishing first. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb.

Answer: A

The current is small so electrocution is unlikely, but the involuntary reaction near a running engine is the real danger. Burns genuinely can occur at the contact point, which makes the last option a real if lesser hazard. The shared behaviour explains why these belong together and the differences explain why both exist. Checking which component actually carries the load settles most questions of this kind at once. The shared properties explain why these belong to one family, and the differences explain why more than one exists.

Answer: B

One is on compression and fires the mixture while the other is on exhaust and sparks harmlessly into spent gas. The pairing is exactly what allows one coil to serve two cylinders, so the reason explains the arrangement. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision. Tracing the requirement back to the physical constraint that produces it makes the answer follow. A symptom that appears under one condition and not another is what narrows the diagnosis quickly.

Answer: C

The reason is correct and it is precisely why the assertion is wrong: a fixed burn time occupies more crank degrees at speed, so the spark must occur earlier. Advance therefore increases with speed rather than decreasing. Reading the definition literally, rather than recalling a summary, avoids the usual confusion. The shared behaviour explains why these belong together and the differences explain why both exist. The order in which the effects act is what decides the outcome, so it is worth establishing first.

Answer: D

The sensor hears detonation after the spark and lets the controller retard, but pre-ignition is caused by a hot spot before the spark and cannot be corrected by timing. The two phenomena need different remedies. Most errors here come from carrying across a result from a neighbouring case where it does not hold. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision. Checking which component actually carries the load settles most questions of this kind at once.

Answer: A

The first two are correct, but a wider gap needs a higher voltage to break down. That is exactly why a worn plug shows a raised firing line on an oscilloscope and misfires under load first. Naming what changes and what stays the same is the reliable route through questions of this shape. Reading the definition literally, rather than recalling a summary, avoids the usual confusion. Tracing the requirement back to the physical constraint that produces it makes the answer follow.

Answer: B

The rotor distributes the spark to the correct cylinder; timing is set by the trigger and the advance mechanisms. The other three pairings are correct, and separating distribution from timing clarifies the whole system. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb. Most errors here come from carrying across a result from a neighbouring case where it does not hold. A single measurement chosen to respond to the one asymmetry beats several that respond to shared behaviour.

Answer: C

The rotor arm handles the high tension output and therefore belongs to the secondary circuit. The primary carries battery voltage through the coil, the switching device and the condenser. The two circuits are diagnosed differently. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb. Working one numerical case through both cases side by side fixes the distinction better than any rule of thumb.

Answer: D

Under load the plug demands more voltage and the spark takes the easier path through the damaged insulation. The visible flicker is direct evidence. A lean mixture genuinely raises the demand, which is why the fault appears only under load. The order in which the effects act is what decides the outcome, so it is worth establishing first. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. A single measurement chosen to respond to the one asymmetry beats several that respond to shared behaviour.