Volkswagen Caddy: 1.5 TSI direct injector clogging — rough idle and hesitation

The direct injectors on the 1.5 TSI clog over time, and poor-quality fuel accelerates it markedly. It shows as a rough idle, hesitation when you accelerate, fuel economy that has quietly worsened, and eventually misfires. Direct injection sprays fuel straight into the cylinder at very high pressure through a very small nozzle, which is why deposits matter more here than on an older port-injected engine — a partially blocked nozzle sprays a poor pattern rather than simply flowing less. On a working van the fuel comes from wherever is convenient, which is part of why this shows up. It is a cleaning or replacement job rather than a mechanical failure, so the value in identifying it is knowing you are not looking at something worse.

• Rough or uneven idle, worst when cold
• Hesitation or a stumble when accelerating
• Fuel economy noticeably worse than it used to be
• Misfire, or an engine warning light
• Engine feeling flat at low revs

Be there for a cold start and sit with it as it idles, because a clogged injector is at its worst then. Listen and feel for an uneven idle or a stumble, and watch the tachometer for a needle that will not settle, then check again with the air conditioning switched on, which loads the engine at idle and exposes a weak cylinder. On the drive, accelerate gently from low revs in a higher gear rather than flooring it, since that is where hesitation shows and hard acceleration masks it. Then accelerate firmly once and confirm it pulls cleanly through. Watch the dash for an engine warning light throughout, and treat a flashing one as a reason to stop. Ask where the van is normally fuelled and whether it is ever run near empty, since both bring sediment into the system, and ask what the fuel economy is and whether it has changed. Ask whether any injector has been cleaned or replaced. If a workshop inspection is possible: ask for stored misfire counters to be read, which name the cylinder.

Parts involved: Fuel injector.

$500 to $2,400 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the fuel economy got noticeably worse?”
• “Where is the van normally fuelled, and is it often run near empty?”
• “Have any injectors ever been cleaned or replaced?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.