TSI (Cupra 4WD) Engine noisy on start up

[seatgraham]

Hi

Mk3 leon cupra 300bhp 4WD TSI Estate/ST (2019)

Noticed it being noisy on start up a couple of times.
Wife was outside car and asking why I continued to start it after engine started. But it's push button start. But that might give an idea of the sound.
I think the car is not running as efficiently too. Never great economy but mpg seems a bit down - although some shorter, low speed runs recently.

Any ideas?

 

[nd-photo.nl]

Any chance to shoot & upload a video?

 

[SRGTD]

Hi

Mk3 leon cupra 300bhp 4WD TSI Estate/ST (2019)

Noticed it being noisy on start up a couple of times.
Wife was outside car and asking why I continued to start it after engine started. But it's push button start. But that might give an idea of the sound.
I think the car is not running as efficiently too. Never great economy but mpg seems a bit down - although some shorter, low speed runs recently.

Any ideas?

A bit of a shot in the dark, but could it be that your car’s GPF is trying to complete a forced regeneration?

If driving a higher proportion of longer journeys when the engine’s up to optimum operating temperature, accumulated particulate matter in the GPF will burn off passively. However, if you’re driving a high(ish) proprtion of shorter journeys on a cold engine, the exhaust temperature might not be getting hot enough to neutralise accumulated particulate matter in the GPF passively, so the car will initiate a forced regen - more short journeys will mean a higher frequency of forced regens, and if the forced regeneration process is interrupted before it’s completed then it’ll recommence at the next (and subsequent) ignition cycle(s) until it’s finished.

The forced regen process uses additional fuel to help raise the exhaust temp to neutralise accumulated particulate matter in the GPF and that might help explain your increased fuel consumption.

When I had my VW which had a GPF, tell-tale signs of a forced regeneration were;

• significantly increased fuel consumption (by around 30-35%)
• a gruff ‘throaty’ exhaust note (could that be what you’re describing as a noisy engine?)
• slight hesitancy under acceleration and a slight jerkiness in stop/go traffic
• stop/start function is disabled
• engine cooling fan runs continuously when the engine gets up to temperature until the forced regen has finished

In my car, the regen process took around 30 minutes to complete, then everything went back to normal.

 

[seatgraham]

A bit of a shot in the dark, but could it be that your car’s GPF is trying to complete a forced regeneration?

If driving a higher proportion of longer journeys when the engine’s up to optimum operating temperature, accumulated particulate matter in the GPF will burn off passively. However, if you’re driving a high(ish) proprtion of shorter journeys on a cold engine, the exhaust temperature might not be getting hot enough to neutralise accumulated particulate matter in the GPF passively, so the car will initiate a forced regen - more short journeys will mean a higher frequency of forced regens, and if the forced regeneration process is interrupted before it’s completed then it’ll recommence at the next (and subsequent) ignition cycle(s) until it’s finished.

The forced regen process uses additional fuel to help raise the exhaust temp to neutralise accumulated particulate matter in the GPF and that might help explain your increased fuel consumption.

When I had my VW which had a GPF, tell-tale signs of a forced regeneration were;

• significantly increased fuel consumption (by around 30-35%)
• a gruff ‘throaty’ exhaust note (could that be what you’re describing as a noisy engine?)
• slight hesitancy under acceleration and a slight jerkiness in stop/go traffic
• stop/start function is disabled
• engine cooling fan runs continuously when the engine gets up to temperature until the forced regen has finished

In my car, the regen process took around 30 minutes to complete, then everything went back to normal.

I wondered about that and does sound possible.
Wasn't sure about the ignition though.
Sounded as though car was trying to start after already started from a cold start...?

 

[seatgraham]

Any chance to shoot & upload a video?

Will try to get video - but typically, the problem didn't show today!
Always more tricky to diagnose intermittent issues...