Frank Massey's Top Ten Tests with PicoScope

Frank Massey applies PicoScope to real workshop situations. These videos were made about 6 years ago but take the trouble to watch them because they contain valuable diagnostic insights.

Throughout this series, Frank discusses the theory of testing, what is being tested and how the use of a PicoScope simplifies the procedure. His demonstrations cover time-bases, voltage ranges, and, of course, the physical connections required.

Frank's unique approach emphases efficiency and speed to optimise the diagnostic process and reduce costs. He suggests, for instance, that one should read an Amp Clamp's voltage output to reduce setup time. With PicoBNC+, vertical scales are automatically converted to the correct unit as soon as you plug in the accessory (e.g. Amps for a Current Clamp) so it is no longer necessary to measure current using volts and do confusing mental calculations and conversions.

We have used letters (A-J) to identify the tests in this series to distinguish them from Pico's Top 10 Tests.

Test A: Cranking current

In the first video, Frank discusses using PicoScope to observe battery voltage drop against load, measured as current consumed by the consumer, the starter motor. This simple test measures voltage drop, current draw and rotation speed during cranking. Also see Test 1 of Pico's Top-10 Tests to learn how to check relative compression at the same time.

Running Time 12 min 39 sec.

Test B: Actuator Duty Current

In Frank's second test, he looks at a Turbo Control Actuator and measures the control duty cycle and current applied to the variable vane of the turbocharger. Use your scope in conjunction with other tools, gauges and test equipment to provide a complete picture.

Running Time 11 min 48 sec.

Test C: Air Mass Flow Meter conversion from Digital to Analogue

Frank discusses the type of Air Mass Flow Meter under test, converting a digital signal to an analogue display and evaluates the performance. The Two and Four-Channel Automotive PicoScopes e.g., the 4425A and the 4425A have built-in hardware frequency counters which are used in this test. The 8-Channel 4823 does not, but you can use a Maths Channel to display the frequency.

Tip: Use the maths channel if you want to measure frequency on multiple channels.

Frank demonstrates that current consumed by the Mass Airflow Meter appears to be proportional to the (decoded digital) output.

A Mass Airflow Meter controls the current through the sense wire to keep it at a constant temperature. As the airflow increases, heat is extracted from the wire and the current rises to maintain the temperature. Hence, the current consumed is proportional to the air-flow.

Running Time 13 min 37 sec.

Test D: Wide-band Lambda Sensor

Frank demonstrates how to confirm the correct response from the Lambda (Exhaust Gas Oxygen or EGO Sensor) Sensor. He establishes the correct function of a five wire air fuel sensor and compares it with load request (air mass meter).

He also demonstrates how to use filtering to clean up the signal.

Remember that an ECU usually measures current by measuring the voltage across a resistor in series with (i.e., carrying) the current. Hence, the current can appear as a voltage when you measure the Lambda Sensor's output.

A very important diagnostic concept is the fuel response time of the engine. Fuel should be delivered within about 200ms of an acceleration event for most, if not all engines. This delay can be measured at the Lambda Sensor. A longer delay can indicate a variety of potential problems listed by Frank in the video.

Running Time 14 min 46 sec.

Test E: Ignition Profiling

Frank discusses the test setup, how to set appropriate triggering, the use of the Coil-on-Plug or COP probe and determining the spark burn time.

Warning: Always use a 10:1 probe or an attenuator on BNC scopes when examining primary ignition voltage, or you may damage your PicoScope.

Frank then analyses and explains the ignition waveforms he captured in depth and explains the four most important things to look at in ignition systems:

Running Time 22 min 27 sec.

Test F: Power, Ground Current

In Frank's sixth video, he looks at the relationship between current, voltage drop and ground reference.

Consider using the Pico Milli-Ohm and Motor Tester to accurately diagnose potential volt drops that might be caused by bad connections.

Running Time 9 min 39 sec.

Test G: Common Rail Pressure Sensor Testing

In Frank's seventh video, he looks at the performance of the high-pressure pump under full load. Frank analyses common-rail systems and describes the most important characteristics that prove the performance of the pump under full load, from a diagnostic point of view:

Frank demonstrates an efficient test of the system that he developed, which proves the hydraulic efficiency of the system. This test is widely used and is both quick and accurate and proves the integrity of the system.

Running Time 23 min 21 sec.

Test H: Direct Petrol Injection - High Pressure Pump Testing

In Frank's eighth video, he looks at the function of the electronic control unit and hydraulic pump performance of pressure over time. The objective is to understand the importance of rise-time, maximum pressure and pressure hold.

He also presents another 'proof' test, appropriate to direct petrol injection.

Running Time 15 min 39 sec.

Test I: Compression Testing

In Frank's ninth video, he looks at real-time dynamic compression testing with the WPS500X pressure transducer.

Running Time 14 min 58 sec.

Test J: Diesel Particulate Filter (DPF) Sensor Testing

In Frank's tenth video, he looks at diesel particulate filter (DPF) sensor testing, using our PicoScope 4425.

Running Time 12 min 18 sec.