What are the common faults in the ignition system?
4 Answers
Common faults in the ignition system include: difficulty starting, delayed ignition, and engine shaking when the vehicle is stationary. 1. Difficulty starting: Mainly manifests as trouble when starting the vehicle, with normal idle speed and normal acceleration in neutral gear. Occasionally, the vehicle may jerk when starting, and it's prone to stalling when starting on an uphill slope. 2. Delayed ignition: Characterized by heavy muffler noise, backfire in the carburetor during rapid acceleration, higher engine coolant temperature, and weak vehicle performance. 3. Engine shaking when the vehicle is stationary: Primarily occurs when the vehicle is stopped at traffic lights, causing the engine to shake. Increasing the engine speed can help stabilize the operation.
I've been driving trucks for over a decade and often encounter ignition issues. The most troublesome is spark plug problems - too much carbon buildup prevents ignition, and rainy days make starting difficult. Then there's aging ignition coils, especially in winter when rubber shrinks causing electricity leakage, resulting in cylinder misfires and shaking. High-tension wire wear is also common; driving on rough roads for long periods can cause short circuits and sparking, sounding like firecrackers. Loose or corroded battery terminals can prevent starting too, requiring sandpaper cleaning. Control module failures are more complex, with the ECU misreporting codes that even mechanics find troublesome. Unstable alternator output also affects ignition - I once broke down on the highway because of this. Oh, and a faulty crankshaft position sensor can prevent the engine from turning over at all - now that's really frustrating.
I've modified racing cars myself, and ignition system failures significantly impact performance. Incorrect spark plug gaps cause sluggish acceleration, while ceramic cracks lead to misfires, resulting in black exhaust. When upgrading to high-power ignition coils, be cautious—poor heat dissipation can cause them to melt. Distributors are common in older cars; burnt platinum contacts cause unstable idling, and adjusting the gap is particularly tedious. Aging high-voltage wiring with electrical leakage may show blue sparks under the hood. When the ECU receives incorrect RPM signals, the engine may start but fail to accelerate—these intermittent faults are the hardest to diagnose. Idle control motors can seize, causing frequent stalls in traffic, requiring disassembly and cleaning of the valve body. I recommend regularly checking the ignition system, especially for modified cars.
I've been working in an auto repair shop for twenty years, and ignition failures are a daily occurrence. The most common issues are spark plugs reaching the end of their lifespan or being the wrong model, which immediately causes fuel consumption to skyrocket. Cracked or leaking ignition coils are the most annoying, making it hard to start a hot engine. Damaged insulation on high-voltage wires causing sparks is especially dangerous on rainy days. If the battery doesn't have enough charge, you'll just hear clicking noises without the engine starting. Cracks in the distributor cap can cause cross-firing, and a worn distributor rotor leads to fluctuating RPMs. A faulty crankshaft position sensor is the worst—after the dashboard lights flash, the car just dies. A malfunctioning camshaft position sensor disrupts ignition timing and causes knocking. Burnt contacts in the ignition switch can also prevent the car from starting. Actually, 90% of these issues can be avoided with regular maintenance.
