The ignition system is a key part for car, which is also the source of many faults. If we went to troubleshoot problems, we must be in-depth analysis and to explore the ignition system fault diagnosis and maintenance. Taking Toyota Corolla ignition system as the analysis object, explore its fault diagnosis and maintenance , hope to help maintenance technicians to repair ignition system problems.

Ignition system with distributor

In the conventional ignition system, the current flows into the coil and be intensified field, routed through the distributor via contact with rotor on the distributor. The distributor is driven by the engine’s camshaft. As it rotates, the cam pushed the points open and close. Each time the points open, the flow of current is interrupted through the coil, collapsing the magnetic field and producing a high voltage surge through the secondary winding. Toyota Corolla use the electronic ignition system, which use semiconductor component to produce pulse signal to ignite. The current of Toyota ignition coil can be switched on and off directly, at the same time, the high voltage current in secondary circuit was distributed to the spark plug through the distributor and jump spark. If accompanied with failure, its diagnosis and repair need to pay attention.

Toyota Corolla ignition system overview

Electronic control ignition system of Toyota Corolla can control the current time of primary winding, also can eliminate the original vacuum type, mechanical centrifugal ignition advance angle adjustment device. Instead of electric control unit, the ignition advance angle is adjusted and controlled reasonably by the actual engine speed to achieve optimal performance, economic performance and power performance. In addition, detonation feedback in electric ignition system is knock sensor, when the operation engine is in critical state of detonation, engine performance can be maximum.

Toyota Corolla electronic ignition system components are spark plug, signal generator, ignition electronic components. The ignition system eliminates high tension wire and distributor to obtain a better ignition performance. Meantime it can control the ignition advance angle, interval angle precisely and work reliably. 

Fault diagnosis of ignition system in Toyota Corolla

Common system failures and Toyota Corolla ignition system fault positions

The ignition system is the core of the automobile electronic control system. It will develop towards the direction of electronization and intelligentization, making the ignition devices more light, small, low-cost and integrated.

1. The spark plug, focused on the fouling, corrosion, error model, carbon deposit and so on. There will be a spark plug gap which is too big or too small, resulting in a direct impact on the ignition voltage. But for the failure of high tension cable, it will be affected by fracture and wear due to its insulation performance. So once a high impedance comes on, there will be abnormal voltage values.

2. Distributor fault, contact-breaker gap is too small or too big, distributor housing broken. 

3. The ignition coil, the short circuit of secondary winding or the grounding primary winding lead to secondary voltage value peak decreases, even the secondary voltage will not produce again. The breakage of the insulating layer also can reduce secondary voltage value peak, and then secondary voltage cannot produce normally.

4. Too thin or thick air-fuel mixture, in fact, its concentrations does not lead to the ignition system failure, but the concentration affect secondary voltage combustion time, which can be reflected through the secondary ignition wave.

 Detection of ignition system failures

The ignition system failures of Toyota Corolla mainly includes spark plug fault, ignition controller (ignition coil) assembly fault, signal circuit fault, feedback signal circuit fault, etc.