Starting Systems Questions and Answers

Answer: A

One to two hundred revolutions per minute is enough for a petrol engine, while a diesel needs rather more to reach compression temperature. Idle speed is far higher. Below the minimum the engine will not fire however good the spark. Reading the definition literally, rather than recalling a summary, avoids the usual confusion. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. The quantity that varies and the quantity that does not are worth naming before any substitution is attempted.

Answer: B

Compression ratios around eighteen to one demand far more cranking torque, and the charge must reach the self ignition temperature. That is why diesels use bigger starters and glow plugs. Diesels have no spark at all. Most errors here come from carrying across a result from a neighbouring case where it does not hold. The order in which the effects act is what decides the outcome, so it is worth establishing first. The quantity that varies and the quantity that does not are worth naming before any substitution is attempted.

Answer: C

A glow plug heats a small region of the combustion chamber so the compressed charge reaches ignition temperature from cold. Grid heaters in the intake genuinely serve the same purpose on many larger engines, which makes the last option a real alternative. Naming what changes and what stays the same is the reliable route through questions of this shape. Checking which component actually carries the load settles most questions of this kind at once. Working one numerical case through both cases side by side fixes the distinction better than any rule of thumb.

Answer: D

Glow time is shortened as the engine warms and afterglow continues briefly to reduce smoke and noise. Continuous operation would burn the plugs out. Simple older systems did use a fixed period, which makes the second option historically real. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb. Tracing the requirement back to the physical constraint that produces it makes the answer follow. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision.

Answer: A

Keeping the plugs energised for a minute or two after a cold start stabilises combustion and cuts the white smoke. Emissions legislation drove its adoption. Stalling is a real risk on a very cold engine, which makes the second option partly true. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision.

Answer: B

A sound plug reads well under two ohms and an open circuit one reads infinity. Current measurement of the set is genuinely a fast way to count working plugs, which makes the last option a real and useful technique. The order in which the effects act is what decides the outcome, so it is worth establishing first. Reading the definition literally, rather than recalling a summary, avoids the usual confusion. Most errors here come from carrying across a result from a neighbouring case where it does not hold.

Answer: C

Carbon seizes the plug in the head and the thin body snaps, leaving a difficult extraction with the head often needing removal. Thread repair is genuinely sometimes required as well. Penetrating fluid and a warm engine reduce the risk. Checking which component actually carries the load settles most questions of this kind at once. Most errors here come from carrying across a result from a neighbouring case where it does not hold. The quantity that varies and the quantity that does not are worth naming before any substitution is attempted.

Answer: D

Most manual vehicles require the clutch pedal to be depressed before the starter will operate. Automatics use an inhibitor switch on the selector instead. Some vehicles genuinely use a gearbox mounted switch, which makes the last option a real variant. Tracing the requirement back to the physical constraint that produces it makes the answer follow. Naming what changes and what stays the same is the reliable route through questions of this shape. Checking the units of each quantity catches a wrong formula before the arithmetic begins.

Answer: A

A switch that never closes leaves the solenoid unenergised and nothing happens when the key is turned. Intermittent operation from partial travel is a genuine variant of the same fault, which makes the last option a real symptom. The shared behaviour explains why these belong together and the differences explain why both exist. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb. Most errors here come from carrying a result across from a neighbouring case where it does not hold.

Answer: B

A relay spares the ignition switch the solenoid current, and on modern vehicles the engine controller commands that relay. Controller commanded starting is now the norm, which makes the last option correct for a current vehicle rather than wrong. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision. A symptom that appears under one condition and not another is what narrows the diagnosis quickly.