Engine Diagnostics in Northampton.

Symptoms worth investigating

• Misfire, shudder or vibration at idle or under load
• Noticeable loss of power or poor throttle response
• Rough or lumpy running when cold, or when warm
• Excessive smoke from the exhaust
• Rising fuel consumption with no change in driving
• Difficult starting, stalling or cutting out
• Rattles, knocks or ticking that change with engine speed

How the fault is traced

The scan is the starting point. From there the tests depend on what the data shows: fuel trims and injector balance for fuelling issues, ignition coil and plug testing for misfires, sensor plausibility checks where readings look wrong, and pressure or leak testing where air or compression is suspected.

The point of doing it in that order is that you end up replacing the part that is actually failing, once, instead of working through a list of likely candidates at your expense.

Diesel specifics

Diesel engines bring their own pattern of faults: blocked or regenerating DPFs, EGR valves sticking with carbon, glow plug circuits, turbo actuators and injector wear. Short urban journeys are the usual cause of DPF trouble, because the exhaust never gets hot enough to burn off soot. EE Motors will tell you whether a regeneration, a clean or a replacement is the sensible call.

Timing chains, belts and noises

A new rattle on start-up or a whine that tracks engine speed is worth checking early. Timing components that fail in service typically take the engine with them, and the difference in cost between a planned replacement and an unplanned one is substantial.

Frequently asked