Intermittent issue polo GTI plus

[Bigbirdkate]

Has anyone had an intermittent issue where the start stop stops working, the fan is always on, the car smells hot when you stop, fuel consumption drops to around 15 mpg, exhaust sounds throaty and power seems to lag? No warning lights on and all fluid levels are fine. Happens in any mode, DSG or manual. Seems to stop on its own after a few days to a week.

This is the 3rd time my car has done this in the 18 months I’ve had it. First time I called VW breakdown out and they said nothing was wrong. 2nd time I tried to book in to VW to get it looked at and they said there was a 3 month wait! It’s done it again now and I’ve booked it in to be seen on the 17th but it probably won’t be doing it by then!

Should I take it to an independent garage and pay for diagnostic while the issue is happening? Anyone else had this? Any ideas what it could be?

[S_94]

Welcome to the forum Bigbirdkate.

Sounds like a regen issue which has been commonly reported by GTI owners. Have a look at this thread: viewtopic.php?f=71&t=73177

I've had my GTI since May 2019 (10,000 miles done) and this has happened to me about three times now. Taking the car for a good 20-30 minute drive should sort the issues out. If you're doing a lot of short journeys that could be what's causing it.

[Bigbirdkate]

Thanks, sounds like the same issue. I will take it for a longer drive tonight. I tend to do very short journeys so makes sense. Hopefully it will sort it.

[SRGTD]

As @S_94 has said, it’ll be the GPF going through the regeneration process. The symptoms of the particulate filter going through the regeneration process are described in the owner’s manual (p236). It only makes reference to the Diesel particulate filter in the text, but symptoms are pretty much the same - from the manual;

Function
The particulate filter (depending on the vehicle equipment) filters out soot particles in the exhaust gas.
Regeneration
In normal vehicle operation, the filter cleans itself. If it is not possible for the filter to clean itself, for example if the vehicle is only ever used for short trips, the filter will become saturated with soot. The diesel particulate filter requires cleaning (regeneration).
Noises, slight smells and increased engine speeds may occur during regeneration. The radiator fan may run on while the vehicle is moving or when the engine has been switched off.
To assist the regeneration of the particulate filter, Volkswagen recommends that you avoid making only short journeys.

@Bigbirdkate; It’s good to know that you don’t need to take it to the dealer for investigation . Regularly giving your car a decent run would also be good for its general mechanical health as it’d give the engine a chance to get up to normal operating temperature which it’s unlikely to do on short journeys. Not so easy to just go for a drive under lockdown though as I dare say the police wouldn’t consider just going for a drive to stop your car’s GPF getting clogged as an essential journey if they were to stop you! .

I’ve yet to experience a GPF regeneration in my GTI+. I’ve owned the car for almost five months, but haven’t covered 2,000 miles yet (a consequence of lockdown!). I’d say that probably 70% of my journeys are 25 - 30 miles or longer, so that might be sufficient to keep the DPF clear, or at least clearer for longer.

It’s interesting that I’ve not seen any mk7.5 Golf GTI or R owners (2.0 litre EA888 engine) with GPF equipped cars on other forums reporting that they’ve experienced regeneration symptoms with their cars.

[monkeyhanger]

Definitely a GPF regen, our first happened at 5k miles then every 2k mikes thereafter. Getting it warm and coming off the throttle to slow down helps (pulls excess air though the engine to allow oxygen to burn the soot in the GPF. If your driving ste is always on the accelerator or the brakes, not enough oxygen gets through the GPF to burn the soot to CO2.

The most shocking thing with aGPF regen is the fuel economy drop. With a Diesel undergoing a DPF regen its about 10% thirstier, with a petrol undergoing GPF regen its about 40% thirstier.

[lancslad1985]

Mines done this twice, including a couple of weeks back. Get the engine warmed up, stick in sport mode (if it’s not massively slippery) and manual. I take it 15 mins down the motorway (7.5 mins each way) getting it to 4000 rpm then just taking my foot off until it dropped to 2000 rpm then repeating after monkeyhanger suggested getting it to engine brake previously.

The engine then seems to go back to normal after that. It’s isn’t half noisy when it’s regenerating though.

[Stuart_Rendall]

Strangely I am coming up to almost 10,000miles with 90% of my journeys being more than 30miles and not noticed a regen yet (car is OPF/GPF model).

[TheRacingRat]

I think you’ve answered your own question Stewart! Lots of longer journeys=less GPF regent. At 3k on mine and no regen yet.

[OomStu_ZA]

Thank heavens we dont have them installed here in ZA from factory so one less problem to contend with.

[West Riding Limited]

Had what was presumably my first regen this morning at 2700 miles. I noticed that the gearbox seemed jerkier and held on to gears for longer, engine and exhaust sounded louder, stop/start and the Eco coasting thingy (don't know what it's called, when you take your foot off the gas in Eco mode but don't brake and it stays in gear with minimum power) disabled, and at one point a burning smell in the cabin. Didn't feel any loss of power, but when I got to work MPG was 26 as opposed to an expected 40+.
Seems back to normal coming home.
My commute is 16 miles on a mix of roads so I use a mix of driving styles once the engine has warmed up, seems this isn't quite enough to avoid a regen then.
I have to wonder what is the point of filtering out the crud only to then burn it off all at once and use up more fuel doing so...

WRL

[monkeyhanger]

Had what was presumably my first regen this morning at 2700 miles. I noticed that the gearbox seemed jerkier and held on to gears for longer, engine and exhaust sounded louder, stop/start and the Eco coasting thingy (don't know what it's called, when you take your foot off the gas in Eco mode but don't brake and it stays in gear with minimum power) disabled, and at one point a burning smell in the cabin. Didn't feel any loss of power, but when I got to work MPG was 26 as opposed to an expected 40+.
Seems back to normal coming home.
My commute is 16 miles on a mix of roads so I use a mix of driving styles once the engine has warmed up, seems this isn't quite enough to avoid a regen then.
I have to wonder what is the point of filtering out the crud only to then burn it off all at once and use up more fuel doing so...

WRL

The point is that it emits CO2 rather than releasing soot particles that get breathed into the lungs. The fuel penalty for an active regen is huge on a petrol car with GPF as opposed to a diesel car with a DPF though.

[fazzy]

There is only one solution: Remove the GPF, remove software in the ECU - hassles and problems with GPF are gone. Keep the GPF in the garage, install before the sale or RW test.
Result: more power, better response, better sound and no regens.

[Andy Beats]

Didn't feel any loss of power, but when I got to work MPG was 26 as opposed to an expected 40+.
Seems back to normal coming home.
My commute is 16 miles on a mix of roads so I use a mix of driving styles once the engine has warmed up,

40+ MPG, mixed driving...?
Lucky if I got that in my 95bhp, never mind the Gti.
Genuine question, do you live in one of those flat counties in England where you can see for miles and miles?
They're a bit alien to us Scots, but obvious why they'd be beneficial to MPG

[Andy Beats]

There is only one solution: Remove the GPF, remove software in the ECU - hassles and problems with GPF are gone. Keep the GPF in the garage, install before the sale or RW test.
Result: more power, better response, better sound and no regens.

Are GPFs under the same MOT scrutiny as DPFs?
Removal is a no-no these days, although leaving them in and gutting the internals is still unlikely to be discovered.
Don't know what an RW test is.

[SRGTD]

Are GPFs under the same MOT scrutiny as DPFs?
Removal is a no-no these days, although leaving them in and gutting the internals is still unlikely to be discovered.
Don't know what an RW test is.

I think they are subject to the same scrutiny. I dare say that if you’re using a GPF-equipped car on public roads in the UK, removal of the GPF might also invalidate your insurance if you’re unlucky enough to be involved in an accident, the insurance company inspects your car and discovers the GPF or its internals have been removed.

I’d hazard a guess that an RW test is a road worthiness test - the equivalent of the UK’s MOT.