Guides
WaveAssist Pro Guides
Practical diagnostics reference for automotive scope work and engine-sound analysis. Start with the fundamentals, or jump straight to the pattern you're chasing.
Prerequisites
Verify these before trusting any waveform, scan-tool reading, or drivability diagnosis.
Oscilloscope fundamentals
Start here if you're new to lab scopes or need a refresher on setup and controls.
- Automotive oscilloscope guide
What a scope does, choosing probes, safe hookup, and the patterns that matter most.
- Triggers & timebase
Pick the right trigger mode and timebase so the event you care about lands on screen.
- Current clamps for engine diagnostics
Read starter, injector, and parasitic-draw currents without breaking any circuit.
- ROTKEE sensors on PicoScope
What to set for the PS16, PDS and VS, what ROTKEE publishes, and what nobody knows yet.
Waveform patterns
Deep dives on the shapes that reveal misfires, weak coils, bad injectors, and dead cylinders.
- Ignition waveform diagnosis
Firing line, spark line, coil oscillations — decode secondary and COP patterns.
- Fuel injector waveforms
Voltage and current signatures for saturated and peak-and-hold injectors.
- Relative compression test
Find a dead cylinder in five minutes with a starter current capture.
- CAN bus diagnosis
Capture CAN-H and CAN-L, check termination, and spot bus-off and voltage faults.
- Known good waveforms
Why stored reference captures mislead, and what to compare against instead: physics baselines and cylinder-to-cylinder comparison.
- Automotive oscilloscope: how to read waveforms
What a lab scope does, how to hook it up, and the three-pass method for reading any automotive waveform.
- In-cylinder pressure analysis
Read a running compression trace: peak, the two pockets, exhaust/intake ramps, intake closing — then confirm with a second test.
Working with capture files
Get your scope files into WaveAssist Pro quickly and without data loss.
Practical techniques
Field workflows for the hardest, most profitable faults.
Engine sound diagnostics
When the scope isn't out, your ears (and a phone recording) still catch a lot.
- Engine sound diagnostics overview
What noises to trust, how to record them cleanly, and how to feed them into the analyzer.
- Sound diagnostic checklist
Step-by-step checklist for recording clips and gathering data so the AI gives its best diagnosis.
- Knock vs bearing noise
Tell spark knock, rod knock, main rumble, piston slap, and wrist-pin tick apart.
- Belt & timing chain noise
Serpentine squeal, tensioner rattle, chain slap at cold start, VVT actuator tick.
WaveAssist Pro testing standard · CSV, pictures & sound
Before You Capture: A Reliable Testing Checklist
Good diagnosis starts with usable data. Use this checklist from the first observation through testing and confirmation. Follow the applicable vehicle procedure and check these conditions before recording.
- Identify the vehicle and concern. Correct year, make, model, engine, symptoms, and relevant fault codes.
- Know the test conditions. Idle, cranking, fixed RPM, or load; required temperature and test prerequisites.
- Check equipment and connections. Correct probes, connection points, grounding, scaling, units, and recording settings.
- Verify relevant power and grounds. Check component supply voltage and ground voltage drop under load where applicable.
- Control comparison tests. Keep the setup and starting conditions consistent. Change only what the procedure specifies.
- Consider outside influences. Weather, altitude, cold-soak conditions, and software/calibration when relevant.
- Inspect capture quality. Avoid clipping, inadequate sampling, unreadable scales, and excessive background noise.
- Confirm before condemning. Check repeatability and independently verify questionable readings.
Keep the test controlled. An idle comparison must start at comparable idle conditions. A 1,000-RPM throttle change introduces another variable. An RPM drop caused by disabling an injector is part of the test response: record it rather than masking it.
Apply the checklist to your recording
Vehicle and test context. Know which engine and operating state you are testing. When weather affects the concern, note ambient temperature, humidity, barometric pressure or altitude, and cold-soak duration. Check PCM/ECM calibration and applicable bulletins when software may explain the behavior. Keep these details in your job notes.
CSV waveforms. Label every channel and retain its units, probe ratio, and calibration. Zero current clamps as specified. Choose range, sample rate, timebase, and record length that preserve the event without clipping. For baseline/commanded comparisons, keep connections and acquisition settings identical, meet the procedure’s starting conditions, and record RPM throughout. Use simultaneously recorded channels for timing relationships; separate files are comparisons, not automatically synchronized evidence.
Waveform pictures. Show the complete relevant trace, channel labels, voltage/current/pressure scales, timebase, and trigger information. Keep the display settings consistent between pictures. Check that labels and event details remain readable after saving. A zoomed image can explain a local event, but include the wider view when repetition or timing context matters.
Sound recordings. Keep microphone location, distance, orientation, device, and gain consistent. Match starting RPM, temperature, and accessory load. Avoid clipping, handling noise, wind, and unrelated shop noise. Include enough stable recording before and after a specified change to hear its effect; document any automatic recording adjustments that cannot be controlled.
Injector-disable example. Establish idle and record the baseline. Disable only the injector specified by the procedure, identify the change, and record the response. Do not raise throttle by 1,000 RPM to make the second capture look different or conceal the response. Restore the injector and check recovery before repeating. Apply the procedure’s tolerance to starting conditions; there is no universal RPM tolerance for every test.
Power, grounds, and physical confirmation. Where relevant, check loaded supply voltage at the component and voltage drop across its ground path and relevant engine/chassis grounds. Battery voltage alone does not verify component supply. Cross-check suspect electronic readings with an appropriate independent measurement: a vacuum-gauge comparison to MAP must account for atmospheric pressure because MAP is absolute pressure; infrared surface temperature is not a direct coolant-temperature measurement.
Check before repeating or replacing. Inspect the first recording before collecting more of the same. Correct unusable data first, then check repeatability and recovery where practical. Following this checklist improves evidence quality; it does not alone prove that a particular component is faulty.