MajorCommonEngine

MG ZS: 1.0 T-GDI: intake valve carbon build-up, misfires and hesitation

1.0 T-GDI: intake valve carbon build-up, misfires and hesitation is a common engine fault on the MG ZS on the 2017 onward cars, and we rate it major. Putting it right costs $600 to $2,500 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 14 documented faults on the MG ZS.

Vehicle: MG ZS
Engine: 1.0L
Years: 2017 onward
Fuel: petrol
System: Engine

This page covers the MG ZS as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All MG ZS faults14 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Diesel particulate filter or Fuel injector or Turbocharger yet. We would rather show none than show a picture of a different part.

What goes wrong

The 1.0-litre three-cylinder turbo is a direct-injection (GDI) engine, so fuel never washes the intake valves and carbon builds up on them, especially on cars used for short urban trips. The result is hesitation, lumpy idle, misfires and a down-on-power feel; several owners have had near-new cars back at dealers repeatedly for misfire faults. Auto cars also run a petrol particulate filter (GPF) that needs regular longer runs to regenerate — constant short trips cause running problems. A walnut-blast intake clean restores performance; ignored, fouled valves lead to coil, injector and eventually valve work.

What you would notice

Hesitation or 'holding back' under acceleration
Rough or lumpy idle when warm
Engine warning light with misfire codes
Poor fuel economy for the size of engine

How to check it

Where to look. Intake side of the 1.0 turbo engine; GPF in the exhaust under the car

Cold-start the engine yourself and listen for uneven idle. On the test drive accelerate briskly from low revs in a high gear and feel for stumble or hesitation. Ask what kind of trips the car does — a short-trip city car is the worst case. Have any stored misfire codes read before purchase.

Parts involved: Diesel particulate filter, Fuel injector, Turbocharger.

What it costs to put right

$600 to $2,500 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.

Ask the seller

“Has it ever been back to the dealer for misfires or hesitation?”
“Has the intake ever been carbon cleaned?”
“Does the car mostly do short trips?”

Now check the MG ZS you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

MG-Rover.org thread: Misfire/timing type fault with new ZS Auto 1L turbo
MG-Rover.org thread: MG ZS known issues (GPF regeneration problems)
FixMyCar / Bumper MG ZS common problems guides

MG ZS buyer questions

Is 1.0 t-gdi: intake valve carbon build-up, misfires and hesitation serious on a MG ZS?

We rate it major and common on the MG ZS. The 1.0-litre three-cylinder turbo is a direct-injection (GDI) engine, so fuel never washes the intake valves and carbon builds up on them, especially on cars used for short urban trips. The result is hesitation, lumpy idle, misfires and a down-on-power feel; several owners have had near-new cars back at dealers repeatedly for misfire faults. Auto cars also run a petrol particulate filter (GPF) that needs regular longer runs to regenerate — constant short trips cause running problems. A walnut-blast intake clean restores performance; ignored, fouled valves lead to coil, injector and eventually valve work.

How much does it cost to fix on a MG ZS?

$600 to $2,500 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which MG ZS years are affected?

Our research records this fault on the 2017 onward MG ZS. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.