Fault Finding & Diagnostics
Accurate diagnosis, using the right tools and experience to get to the root cause and keep you on the road.
From intermittent electrical gremlins to poor running, starting issues and carburettor-related drivability problems, we use a methodical approach to diagnosing faults rather than guessing and replacing parts unnecessarily.
Why Proper Diagnosis Matters
Classic cars are different from modern vehicles. Their mechanical and electrical systems are simpler, but faults can be less obvious and often interconnected. Many issues are symptoms rather than the real cause, and replacing parts without proper diagnosis can be costly, time-consuming and unnecessary. Our experience with classic vehicles helps us identify the true cause, saving you time, money and frustration.
What We Diagnose
- Poor running & misfires
- Starting & charging issues
- Carburettor & ignition faults
- Electrical gremlins
- Overheating & cooling issues
- Intermittent faults
- Suspension & handling faults
Typical Faults We Help With
Ignition faults
Misfires, weak spark, faulty distributors and ignition components.
Charging system problems
Alternator, dynamo, regulators and charging circuit faults.
Fuel and carburettor issues
Tuning, mixture problems, fuel delivery and carburettor faults.
Poor starting
Hot or cold starting issues, fuelling, ignition and electrical checks.
Gauge and wiring faults
Inaccurate gauges, faulty senders, wiring issues and electrical faults.
Suspension and handling faults
Knocks, poor ride quality, vague steering, alignment and stability issues.
Overheating & cooling issues
Cooling system faults, temperature control and general running problems.
Intermittent electrical faults
Occasional cut-outs, poor connections, earth faults and hard-to-trace electrical issues.
How a Diagnosis Actually Works
We start by talking through exactly what the car is doing — when it happens, under what conditions, whether anything's been touched recently. From there we work through the system methodically: checking the straightforward possibilities first, ruling things in or out with evidence rather than assumption, and only moving to more invasive checks once the simpler explanations are exhausted. If a fault needs to be replicated to catch it in the act — a long run, a fully warmed engine, a specific load — we'll do that rather than guess from a five-minute look on the ramp.
What You Get
A written diagnosis report explaining what we found, what's causing it, and what the fix involves — before any repair work is authorised. If the cause turns out to be something that needs further investigation once we're into the job, we'll tell you that too, rather than quietly padding the bill with parts that were never the problem.
What's Excluded
The diagnosis fee covers identifying the fault, not the repair itself — rectification is quoted separately once we know exactly what's needed. On faults that are genuinely intermittent, we'll be upfront if more time or a specific set of conditions is needed to catch it reliably, rather than promising a same-day answer we can't stand behind.
Frequently Asked Questions
My fault is intermittent — can you still diagnose it?
Intermittent faults are exactly where methodical diagnosis matters most. We build a picture from when and how the fault occurs, check the likely causes systematically, and where needed replicate the conditions that trigger it rather than guessing at a fix.
Do you diagnose electrical faults on old wiring looms?
Yes — old cloth looms, deteriorated earths, and non-standard wiring from decades of previous repairs are common on classics, and it's one of our most requested diagnostic jobs.
What if the previous garage already tried replacing parts?
That's a very common starting point for us. We start again from the symptoms rather than assuming the earlier parts-swapping ruled things out correctly, since it often hasn't.