Get to the cause of the engine fault
Rough running, hesitation, poor power or a fault that keeps returning needs more than another part fitted against a code. At Llandow Tuning, we investigate petrol and diesel engine behaviour for owners and garages, including vehicles already repaired elsewhere.
Start with our free code scan, printout and initial assessment. We make a diagnostic plan from the findings, discuss the next useful tests and then explain the appropriate repair or further investigation.
Which engine problem needs investigating?
Misfires & rough running
Cold starts, uneven idle, hesitation and faults remaining after plugs, coils or other repairs.
Turbo & boost faults
Underboost, overboost, limp mode and power loss before deciding whether a turbo needs replacing.
Injector & fuelling faults
Investigate the vehicle first, then decide whether supported petrol or diesel bench testing helps.
Non-starts & starting faults
Failure to start, difficult starting, starting then stopping and relevant immobiliser warnings.
How the investigation develops
- Free scan and assessment. Review symptoms and repair history, read stored codes where communication is available and provide the scan printout.
- Agree the diagnostic plan. Explain useful measurements and checks, and discuss the scope of further chargeable work.
- Test the suspected cause. Compare evidence under suitable conditions; select further tests if the cause is not yet established.
- Discuss repair and verification. Explain the findings and next step, including separate repair work and relevant checks afterwards.
Measurements that help answer engine questions
Manufacturer diagnostic tools and live data let us examine what the control unit reports. Pico oscilloscope measurements help investigate signals and component operation. In-cylinder pressure analysis helps assess compression, valve events and timing-related running behaviour where appropriate.
Fuel analysis, mixture and emissions measurements, and supported injector testing can help investigate fuelling and combustion concerns. Logging under load is used when the vehicle's condition and test plan make it suitable.
See our workshop tools and facilities and ASNU petrol and Delphi diesel injector testing. Each test has its own scope and limits; equipment alone does not establish the diagnosis.
A fault that keeps returning deserves another look
Tell us what happened before and after each repair. Bring codes, invoices, measurements and logs. Intermittent faults may need more than one observation period, and some mechanical concerns require access to components or dismantling.
Related services include ECU testing, DPF diagnostics, AdBlue diagnostics and EGR diagnostics and repairs.
Fault diagnosis before performance work
We investigate standard cars as well as modified engines. An unresolved running fault comes first. Our engine check-over and fit-to-map check assess a running vehicle before tuning; a tuning inspection examines an existing calibration.