Fire Two Spark Plugs Side by Side, Including Long-Reach Plugs
The SPT105 fires two removed spark plugs in open air at the same bench setting so you can compare spark strength and continuity through a transparent cover. Height-adjustable sockets fit plugs with longer terminal ends. It tests spark plugs only; it is not a full ignition-system diagnostic tool.
- 2 Test Sockets
- Adjustable Socket Height
- Up to 6000 rpm
- Transparent Safety Cover
- 110 V / 220 V Versions
Key Features
-
Side-by-Side Comparison
Two sockets fire at once, so a suspect plug can be checked directly against a known one under identical conditions.
-
Adjustable Test-Hole Height
Raise or lower the sockets to fit longer spark plug ends used on BMW, Volkswagen, Audi and other models.
-
Rotary Speed Control
A control knob sets the simulated engine speed so you can watch plug behavior at different firing rates.
-
Visual Spark Check
Judge ignition strength, spark continuity and relative performance through the clear cover.
-
Protective Cover
Closing the cover before testing reduces direct exposure to sparks.
Model Comparison
| SPT101 | SPT105 | SPT301 | SPT360 | |
|---|---|---|---|---|
| Test positions | 2 | 2 | 3 | 5 |
| Adjustable socket height / long plugs | No | Yes | Yes | Yes |
| Simulated speed | 0–6000 rpm | Up to 6000 rpm | 200–9000 rpm | 200–9000 rpm |
| LCD backlit display | No | No | Yes | Yes |
What’s in the Box
- SPT105 spark plug tester
- Power adapter
- User manual
- Retail box

How to Use
- Place the spark plugSeat the plug securely in the test hole, adjusting the height for longer plug ends.
- Close the coverClose the transparent protective cover before starting the test.
- Power on and set speedConnect the correct 110 V or 220 V supply, then set the simulated speed with the control knob.
- Observe and compareWatch the sparks through the cover and compare both plugs at the same setting.
Height adjustment, speed simulation and safety: SPT105 user manual (PDF).
Good to Know
Caution
- Always close the protective cover before testing and keep hands away from the test holes while the tester is working.
- Choose the 110 V or 220 V version that matches your local supply before ordering or connecting power.
Care
- Confirm the plug thread, seat, reach, terminal shape and cover clearance before testing a long plug.
- Confirm any suspected ignition fault with the vehicle procedure; an air-bench result does not reflect real engine load.




















