GTI Engine noises and performance issues

[john896]

Hi, I was wondering if someone may be able to help with regards the mrs polo GTI+ before I take it to the dealers. She noticed a lack of power when she was driving to work a few days ago saying it felt like it was dragging and after about 4 miles could smell burning. She doesn’t drive it fast having only passed her test earlier in the year and always has it in eco mode. I was away so I couldn’t have a look but she stopped driving it in fear of causing any damage. When I got home I drove it about 5/6 miles and could smell burning and the car felt hesitant when cruising along at any speeds. What I did notice was when revving the engine when stationary was the sound of what can only be described as a waste gate(dump valve) which I have never noticed before and thought things like this were only fitted by those who like to modify their cars. She’s had it from new so it’s not modified in any way and only has 1800miles on the clock but something seems wrong. I will be taking it to the dealers and also getting them to try the revving on the demo to make sure it’s not a normal sound but just wondered if anyone else has come across this so I have an idea of what is wrong before the usual dealer fob off. No warning lights are present on the dash and all temps seem normal that I can see.

[MattHGR]

Sounds like your typical OPF/GPF regeneration procedure.
Hesitation, burning smell and a louder sounding engine all line up with this theory.
There will be a thread somewhere in this forum with people in similar situations.

Though I must say, it was normally happening for people nearer 5k miles if I remember correctly.
Bit odd to have the GPF filled up in less than 2k miles.
What type of driving does this car normally do ? Short journeys and traffic crawling?

Sent from my SM-N9750 using Tapatalk

[SRGTD]

@johnn896; It does sound like the GPF was going through the regen process.

This is the discussion thread @ MattGR was referring to;

https://www.uk-polos.net/viewtopic.php?f=71&t=73177

[john896]

It certainly sounds like that’s what’s happening especially as her daily drive consists of about 4miles each way to and from work. You would expect a warning to say that’s what’s happening as she thought her car was on fire and was afraid to drive it anymore until it has been checked. I will give it a good thrashing for 30mins and see if it clears it.

Can anyone confirm if they hear the waste gate vent off if revving the engine with the bonnet up as I have never noticed it before and seems a bit odd.

[monkeyhanger]

It certainly sounds like that’s what’s happening especially as her daily drive consists of about 4miles each way to and from work. You would expect a warning to say that’s what’s happening as she thought her car was on fire and was afraid to drive it anymore until it has been checked. I will give it a good thrashing for 30mins and see if it clears it.

Can anyone confirm if they hear the waste gate vent off if revving the engine with the bonnet up as I have never noticed it before and seems a bit odd.

It's not thrashing it needs, GPFs need air in the exhaust to burn the carbon soot and convert to CO2.

Unlike diesels, there isn't an excess of air when burning fuel - the car pulls in just enough air to manage its oxygen needs tk turn petrol into water and carbon dioxide.

The way to get that excess air through is to have tge car running on no fuel. Get the engine hot (oil up to 90C, about 6 or 7 miles driving) and then drive on dual carriageway at about 70mph, frequently coming off the accelerator and allow the car to decelerate down to 60mph and then take it back up to 70mph and repeat...for about 10 miles. If the road is busy and you don't want to annoy other drivers, you could do same but 75mph down to 70mph and back up again.

[john896]

I get that I just mean give it a good run out stretching it’s legs as it never goes above 40mph and mainly doing 30mph on a daily basis as the mrs doesn’t take it any distance or on dual carriageways. It’s like a caged animal wanting to run.

Do either of yours or your mrs Polos dump the air when revving like it has a dump valve fitted. Never noticed it before and just seems a bit weird when it’s the sort of noise you wouldn’t find out of place on a fast and furious movie or a boy racers Subaru.

[TheRacingRat]

Sounds like your wife may have bought the wrong model of polo. Sounds like the 1.0tsi would have suited her driving better. I take mine on the motorway at the weekend for a blast if it’s been around town all week.

[john896]

Sorry but the 1.0tsi is not a polo GTI in looks or performance so why would she want one of those. I’m sure it’s a more than capable car and will suit some for looks and performance but in mine and her opinion it’s not a patch in looks on the GTI. Also I’m sure the issue of the gpf regen would have still cropped up with that also.

It’s her first car having only passed her test earlier in the year so she is building up her confidence so buying a car with hardly any power would have just meant buying a more powerful one later so it makes more sense to me to cut out the gutless one.

[The Random Dan]

Having it in Eco mode all the time on short journeys probably doesn’t help.

Eco mode is a waste of time, just leave it in normal, you won’t see any negative effects on your fuel efficiency

[stuartrendall]

I drive my car 50% of the time in eco and 50% in individual and I can say there is a massive difference in the 2 especially where I live. I get 50+mpg in eco where as I get about 35mpg in individual. Eco is very helpful imo.

[The Random Dan]

What do you have the individual settings as?

I get 50mpg in normal mode on a good runout

[stuartrendall]

Gearbox in sport, engine sound on eco, steering in sport and suspension in normal.

[monkeyhanger]

I drive my car 50% of the time in eco and 50% in individual and I can say there is a massive difference in the 2 especially where I live. I get 50+mpg in eco where as I get about 35mpg in individual. Eco is very helpful imo.

I bet you try harder to drive sedately and economically in Eco mode, and that's why your mpg is so much better.

Apart from the marginal fains to be had from coasting down hill, all Eco does is blunt the throttle response and change up a gear a little earlier.

You can drive economically with the engine in Sport mode and the gearbox in D mode. There is no magic eco mode for the engine - if you put your foot down in Eco mode, it's not economical, similarly you can drive frugally in Sport mode - it's all in the throttle response.

The GTI engine is economical when it has the Budack cycle running, and that kicks in below about 20kW output, no matter what engine mode you're in.

[monkeyhanger]

Gearbox in sport, engine sound on eco, steering in sport and suspension in normal.

Gearbox in Sport, as in S1, S2 etc. rather than D1, D2 etc?

That'll be why your car is so thirsty.

There's no reason for the gearbox to be in S mode. If you need to hang on to gears, you use the paddles or go full manual mode, then you change up when you're done accelerating.

Engine: Sport, Gearbox: Normal, Engine sound: Eco, Steering: Sport, Suspension: Normal (for comfort).

[stuartrendall]

Gearbox in sport, engine sound on eco, steering in sport and suspension in normal.

Gearbox in Sport, as in S1, S2 etc. rather than D1, D2 etc?

That'll be why your car is so thirsty.

There's no reason for the gearbox to be in S mode. If you need to hang on to gears, you use the paddles or go full manual mode, then you change up when you're done accelerating.

Engine: Sport, Gearbox: Normal, Engine sound: Eco, Steering: Sport, Suspension: Normal (for comfort).

I always drive in manual mode when not in eco. Be a bit pointless using it otherwise. Being in eco helps my economy massively when going to and from family/friends/work as it is really hilly here and being in eco allows the car to go to neutral when going downhill or when approaching traffic and unnecessarily holding a gear.