MRCARTOOL H90 Dual-Hole Spark Plug Tester with 500-9000 RPM Digital Adjustment

Compare Two Spark Plugs Side by Side Under Simulated Engine Speeds

The H90 fires two spark plugs at once so you can compare their ignition strength while simulating real engine conditions, with the simulated RPM shown on a digital display. It is intended for spark plugs from 12V gasoline vehicles.

Dual Test Sockets
500–9000 RPM
Height-Adjustable Sockets
Battery Clamp Power
Digital Display

Key Features

Dual-Socket Testing

Test two spark plugs simultaneously to quickly identify a faulty plug.
Adjustable Socket Height

Accepts standard spark plugs as well as the longer plugs used in BMW, Volkswagen and Audi vehicles.
Battery Clamp Connection

No power outlet needed; connect the clamps directly to the battery.
Digital RPM Control

Turn the knob to set the simulated speed and read the value on the display; different speeds represent different working conditions.

Highlights

Two spark plugs firing in the MRCARTOOL H90 dual test sockets — Two Plugs at Once

Each socket has its own signal lamp for side-by-side comparison.

H90 with a long and a standard spark plug in height-adjusted sockets — Long and Standard Plugs

Raise the socket to fit longer spark plugs.

H90 connected to a 12V battery with red and black clamps — Powered From the Battery

Red and black clamps connect the tester to a 12V battery.

H90 digital display showing the simulated engine speed — Speed on Display

The digital readout shows the simulated RPM as you adjust it.

Basic Version vs H90

	Basic Version	H90
Simulated RPM	0–6000 rpm	500–9000 rpm
HD digital display	No	Yes
Battery clip design	No	Yes
Adjustable socket height	No	Yes
Long spark plug testing	No	Yes
Safety protection cover	Yes	No

What’s in the Box

H90 main unit
Battery clamp cable
User manual

MRCARTOOL H90 main unit, battery clamp cable, retail box and user manual — H90 package contents.

How to Use

Fit the plugsAdjust the socket height and insert each spark plug into a test socket.
Connect the clampsAttach the red clamp to the positive terminal and the black clamp to the negative terminal.
Switch onTurn the switch and observe how the spark plugs work.
CompareAdjust the simulated RPM and compare the plugs under different working conditions.

Good to Know

Caution

Spark plug voltage reaches tens of thousands of volts during operation; never touch the plugs while testing.
Switch off the power before inserting or removing a spark plug.