PX SCRIPT

The Px script uses a pressure transducer installed in place of a cylinder’s spark plug. The script allows for checking the characteristics of the cylinder, intake system, exhaust system and the timing system in order to evaluate the relative impact of these systems on the engine and each other.

This particular software automatically analyzes the cylinder pressure waveform and generates a print out or report with a number of additional parameters and characteristics of the engine and the associated control unit. The calculated values are pneumatic and geometric characteristics of the cylinder; the list of found deviations is displayed in the form of text messages. To improve speed and accuracy of valve timing research, the cylinder pressure waveform is converted into a diagram of the gas amount in the cylinder and is displayed in two different ways, using a script.

This test allows you to:

• To evaluate cylinder leakage
• To measure compression ratio
• Automatically measure the actual valve timing
• To use animations to show the real process of gas exchange that occurs in the cylinder during the measurement
• To identify insufficient filling of fresh mixture into the cylinder (volumetric efficiency), and to determine the cause
• To assess the effect of systems used to force extra air into the combustion chamber
• To evaluate the efficiency of the turbo or supercharger turbine
• To identify excessive cylinder pressures due to control system malfunction of the mechanical or turbocharger, which can cause piston and cylinder damage
• To identify power loss from scavenging exhaust gases from the cylinder including the loss from the turbocharger
• To check the ignition timing advance angle and identify modes of engine operation, in which the measured timing advance angle is later or earlier than optimum
• To check whether the diagnostic test is performed correctly

Signal recording order

• It is recommended to disconnect the fuel injector for the cylinder to be diagnosed if the engine to be diagnosed is equipped with a fuel injection system
• The black alligator clip must be connected to a metal part of the vehicle chassis. The red alligator clip must be connected to the "+" terminal of the battery
• Install pressure transducer Px35 in place of the spark plug for the diagnosed cylinder and connect it to the input №3 of the USB Autoscope IV
• The plug wire for the disconnected and removed spark plug must always be connected to a Spark Gap tester
• If necessary, use the deep well adapter when installing the pressure transducer and a plug wire to connect the Spark Gap tester to the ignition coil. This would be the case with DIS and / or coil on plug type ignition systems
• Connect the Sync transducer to the plug wire that is connected to the Spark Gap tester and connect to the input In Synchro
• Start the engine and allow it to idle
• In the USB Oscilloscope window select mode"Px => Px35" or, if the deep well adapter is used, select the corresponding mode
• Turn on "Record"
• After 3…5 seconds slowly raise the engine speed to 3'000…5'000 RPM with minimum opening of the throttle and then close the throttle
• After the idle speed has stabilized, quickly snap the throttle wide open. Then immediately close the throttle. Alternatively, instead of closing the throttle, you can turn off the ignition while keeping the throttle open until the engine comes to a complete stop. If keeping the throttle open while shutting off the ignition, additional information will be recorded for the script tabs "Inlet" and "Exhaust"
• Turn off the waveform recording
• Save the recorded waveforms
• Next you will need to analyze the recorded waveform

Documentation

	Px script – Manual
	Px script – Examples
	Px script – Common errors
	Px script – Diagnostics: No-Pressure Nissan Won’t Start, Gushes Exhaust Gases
	Px script – PlugIn "Phase measurement"

Waveform examples

	The USB Oscilloscope program is required for waveform playback
	Px - Valve timing too late - Toyota 1999 1.0
	Px - Too late ignition timing - Mitsubishi GDI
	Px - Mazda Tribute 2006 2.3 AT - 01 Restricted exhaust
	Px - Mazda Tribute 2006 2.3 AT - 02 Clean exhaust
	Px - Valve clearance too small - Honda Civic 1992 1.6 16v VTEC
	Px OK - Nissan Pulsar 2000 1.5 GA15DE
	Px - Honda VTEC