Lx1 inductive sensor for diagnosing ignition system

In Stock

The sensor is designed for diagnosing distributor, DIS and COP systems. Two or more ignition coils are diagnosed one by one. The sensor also receives a signal of synchronization from the first cylinder. It’s used for measuring secondary voltage parameters, accessing ignition spark capability and identifying problems related to high-voltage wires, plugs, caps and coils.



ROTKEE (Ukraine)

Number of simultaneously diagnosed coils


Output connector


Supply voltage

not provided

Output Signal Type


Operating temperature range

-20 to 80℃

Recommended Sampling Rate

250 kHz minimum

Signal Cable Length

2.5 m

Housing Material



155 g


Items Included 

  • Lx1 sensor – 1 pc
inductive sensor Lx1 items included

Video Tutorials

Diagnosing an ignition system with the help of a Lx4 sensor and MT Pro automotive oscilloscope, connecting the sensor to the engine, oscilloscope tuning, waveform recording while idle running and increased load. I’ll demonstrate all of this with an example of Seat Ibiza.

Sensor Design

A soft microphone cable with thick braided screen is used as a cord. BNC is used as a sensor-oscillograph connector.

The sensor case is made of polyurethane, which makes a fragile sensor element damage-proof.

While developing the sensor, high emphasis was placed on cable and sensor joints as this junction is damage-prone. This joint includes a circuit board with the sensor’s electronic components. The board not only supports the loads, but also fixes the cable. Such solid joints prevent cable breakdown and increase its durability.

The sensor was developed as compatible with MT-Pro automotive oscilloscope as well as any other oscilloscope, analog channel or synchronizing channel (if used as a synchronizing sensor).

Diagnostic Technique

The detecting element of the Lx1 sensor is an inductance coil. In order to detect a secondary voltage signal, the sensor’s detecting heads are to be fixed on the surface of the ignition coil, within its electromagnetic field. Generally, the upper part of the ignition coil is a flat area for the detecting head to be placed on. Double-sided foam tape will do for the fixing on the coil case. Before assembling, the surface of the coil and sensor is to be cleaned and dusted.

Sensor Operation Principle

The ignition coil of the internal-combustion engine operates on the principle of a step-up transformer and has two windings and a shared core. Therefore, when current strength in the primary winding changes, it triggers emf, which results in current strength change in the secondary winding, and vice versa. If an extra inductance coil is placed in the ignition coil’s electromagnetic field, it’ll cause emf in proportion to the changes in the coil’s magnetic field. This is how a secondary voltage waveform is obtained.

The secondary voltage signal’s shape depends on the sensor’s location in relation to the coil’s electromagnetic field. That’s why when placing a detecting head it’s advisable to keep in mind the following. The symmetry axis of the sensor’s detecting coil is to be placed along the axis of the ignition coil’s core. The distance between the coil and the head is to be as minimum as possible. If you can’t define the ignition coil’s type by eye, you can then change the sensor’s location in relation to the ignition coil until the oscilloscope receives a signal with the biggest amplitude.

The precise Lx1 synchronizing sensor’s location isn’t that crucial, as its function is restricted to detecting breakdown impulse.