Each engine produces a predictable pattern of these pulses which can easily be displayed on your oscilloscope.

The pressure pulse wave is detected, measured and Firstlook sends a signal to the oscilloscope.

Changes or irregularities in the pressure pulse pattern can be linked to problems within the engine.

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Because of this many diagnostics are forced to increase the RPM of the engine thus shortening the ignition cycle thus saturating the waveform of the cycle.

All oscilloscopes have screens on which the waveform is shown.

The screen can be a cathode-ray tube type, a liquid crystal display (LCD) or in the form of a computer program.

The typical oscilloscope screen is divided into equal spaces (divisions) which allow to visually interpreting the parameters of the signal.

The graphics shown on the monitor are called waveforms.

Usually oscilloscopes show only waveforms of the voltage.

This form of visualization shows the change of voltage through time.

The divisions marked on the horizontal(x) axis allow for the time parameters to be measured, and the vertical(y) axis allow for the voltage values to be measured.

Often the problem hasnt recorded an error code (DTC) in the corresponding ECU, a DTC that can be read with a code reader.

Usually a DTC is recorded when there is a broken cable or a cable has short circuited to a positive or negative supply.

But when a detector or a mechanism has stopped working in some mid position, there is no error recorded.

In this case, as when you need to find the reason that caused an error to be recorded the automobile oscilloscope is your most needed instrument.

With the increase of sensors, actuators and wiring diagrams built in the modern automobiles, the automobile oscilloscope is an instrument which diagnoses irregularities in the automobile faster and easier.

The oscilloscope is a irreplaceable tool, when you have to observe output signals from inductive sensors, whose output signals form a impulse sequence, slow-changing analog signals, primary and secondary ignition circuits, intake manifold absolute pressure, starter current waveforms, charging currents and etc.

They show detailed graphics, and can usually show high frequencies, but are not suited for observing short processes repeated through a long time interval or relatively slow processes like the ones in an automobile.

Further more only the current screen shown on the monitor can be saved, and a sequence of many screens can later be opened and observed through time as an animation.

There are two kinds of digital oscilloscopes: independent which are external device, and PC oscilloscopes.

The PC-based oscilloscopes are a new type of oscilloscope that consists of a specialized signal acquisition board, which can be an external USB or Parallel port device, or an internal add-on PCI or ISA card.

In automobile repair, an ignition analyzer is used to show the spark waveforms for each cylinder.

In this way the specialized automobile oscilloscopes are also used for testing injectors, ABS, O2 sensor, quick compression tests, fuel pump, CAN Bus and much more.

In order for the oscilloscope to observe other physical parameters, as well as observing voltages outside its original ranges different types of additional attachments and transformers that convert the given input into voltage are used.

The main difference between a motortester and a universal oscilloscope is that the motortester is capable of visualizing short-timed processes like the ignition spark process.

This process is exceptionally fast, and the period of repeat of the ignition of sparks in time is many times greater than the time the spark itself exists.

This is easily observable when testing the engine in idle speed, when the majority of the measurements are conducted.

For example: if we observe the ignition cycle of a 4 cylinder gasoline engine, and an ignition spark that lasts around 2ms, at 800 RPM, the time period between sparks on a single cylinder would be 150ms.

What this means is that the length of the spark would account for around 2 of the actual work cycle, and therefore the burning of the sparks will be seen as very thin lines on the screen of the oscilloscope, and no information about the phases of the ignition would be seen.

Fuel Injector Oscilloscope Pattern