1.0 TSi 115 occasionally fails to start

[oldglosracer]

Hi there,

We've had our 2020 1.0 TSi Excellence DSG for 2 months now.
We've noticed sometimes it fails to start and then the starter continues and you have to press the button to stop it and then try again.
It always starts the 2nd time.
It's only done 7k miles in 3 years, so I wonder if the plugs are fouled up?
I've put some Shell V power through it, but it still does it sometimes.
Or maybe a failing brake switch kills the starting?
Guess I need to get the fault codes read.

 

[kurac338]

I don't have experience regarding this issue with this particular engine, but I had a similar issue with a Suzuki Swift M13A engine.

The usual culprit would be a dirty throttle body butterfly valve. If enough carbon and oil is stuck around the valve edges, air cannot get through.
This is usually manifested when the engine tries to turn over, but fails due to not having enough air in the cylinders.

A simple cleanup of the valve usually fixes the issue.

You can try to confirm this suspicion before dissembling any thing in the engine bay.
Next time you try to start the car, first push down the throttle pedal a bit to open up the throttle body valve, and than push the start button.

I hope this helps