Px8 pressure transducer

Px8 pressure transducer is designed to assess the engine mechanical condition using an oscilloscope. It allows you to display on the screen of an oscilloscope a waveform of the pressure in the cylinder of an engine in the range -0.95 … +6 Bar (-14 – 87 psi). Px8 is designed to work with USB Autoscope Lite oscilloscope.


130 $


The Px8 pressure transducer is designed to diagnose the condition of the engine mechanical condition using an oscilloscope. It allows you to display on the screen of an oscilloscope a waveform of the pressure in the cylinder of an engine operating on:

  • gasoline,
  • liquefied gas,
  • compressed gas,
  • alcohol-based biofuel.

The pressure transducer is installed where the spark plug vould normally be.

During measurements, it is necessary to disable combustion in the tested cylinder. This can be done with a spark tester and a plug wire adapter.

If the engine is equipped with two spark plugs per cylinder, the second plug wire of the cylinder under test should be connected to another spark tester.

In cylinder pressure waveforms allows you to diagnose the condition of the cylinder and piston , the presence of cylinder leakage from the combustion chamber, measure the actual valve timing, check the operation of the intake and exhaust system of the engine, and also measure the actual ignition timing.

It works with all automotive oscilloscopes equipped with BNC connectors, or suitable adapters.

The USB Autoscope software automatically analyzes the cylinder pressure waveform. The result of the analysis is presented in an easy-to-understand form. The analysis algorithm is called Test Px.

Px Test is the intellectual property of Autoscope Technology. All rights are reserved.

Appearance: px35 pressure transducer
Measured pressure range: -0.95…6 Bar
Sensitivity: ~643 mV / Bar
Output voltage range: 0.225…4.7 V
Formula for converting output voltage to relative pressure in Bar units: P=1.5554519·U-1.3110904
Formula for converting output voltage to absolute pressure in Bar units: P=1.5554519·U-0.3110904
Formula for converting output voltage to relative pressure in PSI units: P=22.560274·U-19.016055
Formula for converting output voltage to absolute pressure in PSI units: P=22.560274·U-4.5120548
Sensitivity: ~643 mV / Bar
Output voltage at atmospheric pressure 1000 mBar (750 mmHg) ~843 mV
Response time: < 1 ms
Maximum duration of measurements: < 2 min
Working temperature range: -20…80 °C
Supply voltage: 8…15 V
Current consumption: < 30 mA
Inlet Thread Size: M14 x 1.25 Male (standard spark plug thread)
Output connector type: XLR MALE
Output connector pinout: 1: Output, 2: GND, 3: +
Diameter: < 30 mm
Length: < 145 mm

Specific points and sections of the in-cylinder pressure waveform of a gasoline engine operating at idle speed. In this form, the waveform can be obtained using any oscilloscope. However, a lot of knowledge and time is needed to properly analyze its characteristic points.

The USB Autoscope software automatically marks the specific points of the cylinder pressure waveform, displays a mask of their permissible positions, as well as the actual value of the deviation from the norm.

For detailed analysis of the cylinder pressure waveform, including in transient engine operating modes, the USB Autoscope software is equipped with the Px script. The script displays the results of the analysis in the form of a detailed and visual report.

It takes only 30 ... 40 seconds to complete the Px test.

The script automatically measures and analyzes the key characteristics of the cylinder, intake and exhaust system, the valve timing mechanism and the ignition timing control system, and provides: - automatic measurement of real valve timing; - assessment of the degree of compression and leakage of the cylinders; - checking the exhaust system; - diagnostics of fixed and variable intake systems, turbo and superchargers, VVT, Vanos, and VTEC systems. - check the ignition timing system.


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