Fire Two Spark Plugs Side by Side and Compare What You See
The AUTOOL SPT101 fires two removed spark plugs in air at the same adjustable rate so differences in spark strength are easy to spot through its transparent cover. It suits most 12 V gasoline car and motorcycle plugs; confirm suspected faults with the vehicle procedure.
- 2 Plug Sockets
- Up to 6000 rpm Simulated
- Transparent Safety Cover
- 100–240 V Adapter
Key Features
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Two-Plug Comparison
Test two plugs at once in sockets A and B and compare their sparks at an identical setting instead of judging one plug alone.
-
Rotary Speed Control
One rotary switch powers the tester on and sets the simulated engine speed; it is a bench firing rate, not real engine speed or load.
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Transparent Protective Cover
The cover shields the operator from the high-voltage test area while keeping both sparks in clear view.
-
Compact Bench Unit
Plug the supplied adapter into the side power socket and start testing.
Model Comparison
| SPT101 | SPT105 | SPT301 | SPT360 | |
|---|---|---|---|---|
| Plug positions | 2 | 2 | 3 | 5 |
| Adjustable socket height | No | Yes | Yes | Yes |
| Long spark plugs | No | Yes | Yes | Yes |
| LCD backlit screen | No | No | Yes | Yes |
| Simulated speed | 0–6000 rpm | Up to 6000 rpm | 200–9000 rpm | 200–9000 rpm |
What’s in the Box
- SPT101 spark plug tester
- Power adapter (plug type varies by region)
- User manual

How to Use
- Seat the plugsWith the power off, place a spark plug in socket A or B, or both for comparison.
- Close the coverLower the transparent protective cover before testing.
- Power onPlug the adapter into the side socket and turn the rotary switch clockwise.
- Adjust and observeKeep turning to raise the simulated speed and watch both sparks through the cover.
Operation, safety and troubleshooting: SPT101 user manual (PDF).
Good to Know
Caution
- Testing generates high voltage. Never touch the plug, socket or test area while powered, and never operate with the cover open.
- Switch off before inserting or removing a spark plug.
- Use only a compatible 12 V 1 A DC adapter.
Care
- Store dry and away from heat, humidity and corrosive liquids.
- Check connections regularly, tighten loose parts and replace aging wires.
- Confirm fitment before testing unusual or non-standard plugs.




















