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solving the GPF mystery

21K views 42 replies 19 participants last post by  mr.macspot 
#1 ·
so...My GPF light came on 2 days after buying the car (used 1 yr 7k miles)
MPG dropped massively, didnt notice too much change in performance
took it back to the dealer in anger and just so happened it switched off by the time I got there.

So anyway...ive done some digging/reading, few posts on here in the past about people having the GPF light come on quite a few times in the stinger and other models and various discussions/confusion about why and what to do with it. others have also noted a drop in MPG/performance. thought id share what I read as may help to clear some confusion

Full article:
The Gasoline Particulate Filter FAQ | | Hypermiling | Fuel saving Tips | Industry News | Forum

summary if you dont want to read the link:
1: Comparing to DPF: GPF has lower capacity, which may explain why it comes on more frequently

2. Passive regeneration, needs high temp and oxygen. however, Petrol engines burn most of the oxygen so regen cant really happen while driving, so it happens on deceleration (since engine still running but without burning petrol so higher O2 concentration available in exhaust)

3. Active regen: occurs if passive fails (e.g. not enough time in deceleration). GPF light comes on, air/fuel mixture changes to forcefully increase amount of oxygen available in exhaust to allow regen to occur (prob explains the drop in MPG and performance)

So to avoid the light coming on (or if it does come on), from what ive understood from the above and other articles is...
its not the fast driving/harsh acceleration on sport that causes regen - but the deceleration
so go up to high speed then just take your foot off the pedals and let the car slow down a bit (as long as its safe to do so!)a few of these passive decelerations every now and then should prevent it clogging up.

on the other hand long motorway miles with constant foot on pedal and without much deceleration prob more likely to cause GPF light to come on.

anyway hope that helps
 
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#2 ·
Thanks for the write up.

I had a similar experience with the car, twice in the first two weeks of ownership but cleared by the next day. I suspect it had been used only intermittently without much passive deceleration (ex-demo).

When mentioned to a dealer friend, he suggested taking it on a highway and sitting in 3rd or so for a few minutes, with the revs up high so as to "clear the filter".... After reading your article it was more the regular journeys and smooth deceleration that cleared it... either way it settled. Since those initial occasions it hasn't happened again.
 
#7 ·
When mentioned to a dealer friend, he suggested taking it on a highway and sitting in 3rd or so for a few minutes, with the revs up high so as to "clear the filter"....
Also known as an Italian tuneup.
Was often the way to help cure carb. problems back in the day!
Over 3 years and 42,000 miles, never had the light come on. Have always used premium grade petrol (mostly Shell 99) perhaps these help keep the filters clean?
 
#3 ·
so...My GPF light came on 2 days after buying the car (used 1 yr 7k miles)
MPG dropped massively, didnt notice too much change in performance
took it back to the dealer in anger and just so happened it switched off by the time I got there.

So anyway...ive done some digging/reading, few posts on here in the past about people having the GPF light come on quite a few times in the stinger and other models and various discussions/confusion about why and what to do with it. others have also noted a drop in MPG/performance. thought id share what I read as may help to clear some confusion

Full article:
The Gasoline Particulate Filter FAQ | | Hypermiling | Fuel saving Tips | Industry News | Forum

summary if you dont want to read the link:
1: Comparing to DPF: GPF has lower capacity, which may explain why it comes on more frequently

2. Passive regeneration, needs high temp and oxygen. however, Petrol engines burn most of the oxygen so regen cant really happen while driving, so it happens on deceleration (since engine still running but without burning petrol so higher O2 concentration available in exhaust)

3. Active regen: occurs if passive fails (e.g. not enough time in deceleration). GPF light comes on, air/fuel mixture changes to forcefully increase amount of oxygen available in exhaust to allow regen to occur (prob explains the drop in MPG and performance)

So to avoid the light coming on (or if it does come on), from what ive understood from the above and other articles is...
its not the fast driving/harsh acceleration on sport that causes regen - but the deceleration
so go up to high speed then just take your foot off the pedals and let the car slow down a bit (as long as its safe to do so!)a few of these passive decelerations every now and then should prevent it clogging up.

on the other hand long motorway miles with constant foot on pedal and without much deceleration prob more likely to cause GPF light to come on.

anyway hope that helps
Thanks. Very interesting even though I’ve never had a problem with mine in the 30 months I‘ve had the car.
 
#4 ·
This is good to know. I came from 10 years of 15-20k mile a year diesel driving with DPF's and never had a single light. I was pretty miffed when mine came on a week after buying the car and it being a petrol with no change to my driving habit! Same as you, shocking MPG and felt juddery on cruise and trying to accelerate but by the time I got home it had cleared and not been seen since.

I suspect like Strobe that as mine was a year old and ex demo with only 1100 miles it has never been properly driven to clear it. I have done nearly 3k miles in the two months since and it has not come on again. The amount of driving I do I reckon I should do enough decelerating through normal use, even if a lot is on the motorway for it to hopefully not be an issue again.
 
#5 ·
That may have solved it !! I am a low mileage owner even more this year, on returning from a trip from Yorkshire after completing 280miles the light came on which I could not understand as I was driving it hard at the time, I slowed down up and down the hills on the moors due to traffic, and then stopped for a coffee the light went off, only to return 2 weeks later, then my dealer done a forced regen :mad: so it looks like I need to find a route now to force my own regen (y)
 
#6 ·
You can't make this up! Same day I said hopefully this won't happen any more and guess what happened on the drive home?!

I did 98 miles this morning to work and 15 miles into the drive home on the motorway at 70 and the yellow GPF light came up on the dash, mpg tanked and juddery ride. I kept driving it for another 20 minutes but the last time this happened the light would only reset after the engine was turned on and off.

I wasn't going to stick with that awful mpg and shuddering for another 50+ miles so pulled into the services after 20 minutes more driving, turned the engine off and back on and the light had gone and everything back to normal. Wish they worked more like a DPF and did it through acceleration rather than deceleration.

The 15 miles up to the motorway I had been hooning it in sports mode with a fair few red lines, wonder if this extra hard driving possibly temporarily clogged it and caused the light or a coincidence? If anything you would think temperatures would be raised and this would clear it.

One thing I have noticed is the exhaust on this even when the engine is completely warm spits out so much water vapour when you boot it. Anybody else noticed this? Floor it at 50 and you can see it all shoot out in your rear view mirror.
 

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#28 ·
One thing I have noticed is the exhaust on this even when the engine is completely warm spits out so much water vapour when you boot it. Anybody else noticed this? Floor it at 50 and you can see it all shoot out in your rear view mirror.
I've noticed this too. Hard acceleration on the motorway, looked in the mirror and there were clouds of water vapour. I can't recall ever seeing this on other cars I've owned, or the other Stinger I had. Maybe I just haven't been looking ! Does seem a bit unusual though.
 
#10 ·
The GPF lamp came on, I have a 2.0 GTs line. Dealer advice was: once up to normal operating temperature, select sport (so the manual gear selected holds) drive at 55 to 60 with engine RPM at 2700 to 3000 rpm for 30 mins. I did this but only for 20 mins. Stopped for petrol on the way home. Upon re-start the lamp was off.
Short journey's caused the issue. Thanks COVID19 !!
 
This post has been deleted
#12 ·
Hi

I had the same GPF warn light come on, after a run it did go out. However the explanation you have put out looks like great advice. I will now let my Stinger 3.3GT do some coast down work after running I do about 20 miles to work mostly motor way driving. So plan is pre slip road for exit to let car cost foot of accelerator and see how she goes, Hopefully never see the pesky light again.
Thanks for the write up, I contacted Kia, they just want the car in to play with and charge me some cash. I will see how it goes will let you know if any further occurrences.

Tony (axeltramp)
BTW its a great car, keep your BMW and Merc, this is such fun to drive and has everything. Head up. display is a revelation.
 
#13 ·
i have had in occur 3 times now and the pattern is consistently about every 4000 miles. Each time it takes a good 40 mins of I constant high revs (at least 2800-3200rpm) with occasional full throttle blasts plus sum engine braking. Seems excessive and I wonder how other petrol engined high performance cars fair. My driving does have a relatively small amount of high speed action so I'm sure it would be less frequent if I was doing more motorway miles
 
#14 ·
The Gpf alarm is on for the 3rd time on my 2020 3.3 stinger.
It will not reset even after a long run and trying sudden deseleration.
Is is also in for its 2yr service and Kia are refusing to treat it as a warranty claim as the car has only done 5000 m.
So it bye bye Kia I wont be buying another one.
 
#20 ·
The GPF light has just come on mine. I've only had the car for a few days. Car was just over three months old and with 2k miles on when I bought it. Since buying it I've done a return trip to Cornwall, (about 850 miles mostly motorway), a few miles locally including a 50 mile A-road run yesterday. Total miles since I bought it is just over 1k. The light came on when I started the car this morning and is still on this evening. If this turns out to be a recurring problem the car will be going in short order.
 
#24 ·
How many miles did you do between the morning and evening? The light coming on isn't a problem, it's if it will never go out that it is an issue.

Mine came on within a couple of days of ownership at 1k miles and probably from all the short journeys it had recently had at the dealership.

Mine came on part way through a 200 mile drive and after I had just been spanking it so the whole drive it hard doesn't seem to change the frequency of it coming on. Mine comes on every 3-4k miles and will always go out after a 30ish mile drive. Fortunately, this is my trip to work so no unnecesary driving needed. As long as it goes out it isn't an issue. If you only do short journeys and the light is stuck on because this is all you do then the dealers have to force and regen and this is unfortunately the future of all petrol cars. GPF's are put in lots of modern petrols with short journey drivers complaining across all manufacturers. Short journeys are rubbish whether you have a diesel or a petrol now. The cynic in me would say it is a way of the EU regs to force us to hybrids and electric 😂
 
#25 ·
I probably did about 50 to 60 miles the day before the light came on. This was at a mixture of speeds and included a bit of town driving. I'm inclined to use engine braking a lot anyway which should be good for the GPF if what I've read is correct.
 
#26 ·
Interesting! Had my Stinger GT for 4 weeks. GPF light came on this morning. Drove the 18 mile commute and back home in the evening, and the light is still on. Reading the above, perhaps it might be best to remove it as my local Kia stealer wants £170 to force a re-gen! The stealer reckoned they just throw a bottle of 'Cat Cleaner' in and leave it ticking over for an hour. Is it possible to remove it entirely?
 
#29 ·
It's possible to remove but you would need somebody who knows how to code out the engine light that will come on and put in a dummy looking GPF in its place or you would fail every MOT, same as if you remove a DPF. Or just find a friendly tester who doesn't care.

They are the future of petrol cars unfortunately.
 
#27 ·
Update on mine.

After a combination of driving conditions, and trying the reset methods described earlier in the thread, the GPF light is still on. I drove about 80 miles today at sensible speeds on A roads with a short stretch of dual carriageway. - average mpg less than 24. At a steady 60/70 on the dual carriageway the car has a noticeable "roughness" which disappears if you put your foot down.

It's booked in tomorrow at the dealers.
 
#30 ·
Update on mine.

After a combination of driving conditions, and trying the reset methods described earlier in the thread, the GPF light is still on. I drove about 80 miles today at sensible speeds on A roads with a short stretch of dual carriageway. - average mpg less than 24. At a steady 60/70 on the dual carriageway the car has a noticeable "roughness" which disappears if you put your foot down.

It's booked in tomorrow at the dealers.
That mileage and speed should have definitely cleared it so good to get it booked in. The roughness is from it overfuelling to try and raise exhaust temperatures to burn it off and why the mpg also tanks. The car feels terrible when it does it.
 
#31 ·
Just got the car back from the dealers, they had to do a regen to clear the light. The regen must use a LOT of fuel as the mpg for the last eighty miles has fallen from 24 to 19.5 and the car hasn't left the workshop.

The technician confirmed that they do have several cases of GPF filter issues. If I could find someone to remove it I would.

Just a thought but could the clouds of "steam" from the exhausts under hard acceleration actually be a product of over-fueling ? Clearly when the GPF light comes on the car fuel consumption drops dramatically and this can only be due to excess fuel being injected.
 
#34 ·
Thanks, @Caliden. My bullet-point summary from reading Hypermiler article and others:
  • GPF = Gasoline Particulate Filter (=PPF, Petrol Particulate Filter} removes tiny bits from exhaust.
  • It's a European 6c emissions requirement for direct injection engines (GDI).
  • When engine gets hot, collected bits evaporate. So it should work forever. Nothing to replace.
  • Cold-engine journeys will accumulate bits and throw up a warning message to drive hot.
  • However, once you get a Kia warning, long drives may not clear the system.
  • When filter blockage detected, temperature raised by burning more fuel (hence lower mpg).
  • Or.. When filter blockage detected, spark timing delayed to burn lean, using more oxygen.
  • Lots of braking can help (eg when going up and down hills or twisty roads).
  • Long drives on motorways, including in lower gears, seem less likely to help.
  • Removing the GPF would fail MOT and likely cause permanent warning and 'limp home' mode.
  • Seems to happen with petrol and MHEV. Less or none with HEVs and PHEVs.
  • Same experience with Hyundai (including unhelpful suggestions).
References:
A word of advice on Kia Sportage GPF (Petrol Warning Light) - Which Mobility Car Forum
Particulate Filter: Is There One In My Petrol Engine? | SINSPEED
The Gasoline Particulate Filter FAQ | | Hypermiling | Fuel saving Tips | Industry News | Forum (from Caliden)
 
#35 ·
Clearly the GPF filter doesn't "work forever" in all cases and requires regeneration by a dealer. Long fast journeys seem to be the main cause of GPF issues which is ironic as the Stinger is designed as a GT car. I wonder if owners in the USA and Australia have the same problem as I imagine they're more likely to complete longer journeys. Are cars in those markets fitted with a GPF or is it confined to EU cars, i.e. just another ill prepared piece of legislation. ? I realise that it's an MOT failure and probably illegal to remove the GPF but I've no doubt that isn't stopping many owners of other brands doing exactly that. If it was a choice between removing the filter or getting rid of the car I know what my choice would be.
 
#36 · (Edited)
I believe it is only the EU market (lucky us) that has the GPF. It makes sense that I get it every 3k miles or so because my car lives on the motorway. The fastest I have ever cleared it was in 10 minutes really early in the morning and I held it in third gear, went up to 80 and coasted down to 60 using engine braking on the motorway. This is the easiest and fastest way but completely unrealistic or safe during 90% of the day. 31k miles in and mine has never stayed on after a drive yet. It either goes out during a drive or not reappeared once turning the car on so hopefully it continues that way.
 
#40 · (Edited)
My GPF light has been on for a week now, with around 150 miles driving and a bottle of Wynns Cat Cleaner in the tank, but that pesky light is still on. So today I tasked myself with trying to get rid of it. What eventually worked was, stick it in Sport to stop it defaulting to "D", select 3rd with the paddles, then drove 16 miles, keeping the revs between 2000 and 4500 all the time. Light went out and all is back to normal. Hope that will be the end of it. It seems it's the on and off the throttle that helps, build some heat in the exhaust, then off the throttle so the higher oxygen content in the exhaust oxidises the ash and cleans the filter.

It'll probably do it again soon, but hopefully I'll have a fix ready if the light comes on again. Love this car, makes me grin!
 
#41 ·
My GPF light come on 3500mils into having the kia sportage mk51.6 GDI, dealer said to do 3 to 4 thousand revs in 4 gear, i did this for 70mils the light was still on so i started to get mad revving the bulls out of the car letting it decelerate at the same time, i didn't know this at the time i was decelerating it because I was that mad how much fuel it was taking, then the light goes off. Now a 1000 mils later its back on as of today 1/2/23, so I google to see the best way of doing it and seen this post then it poped in my head about the deceleration, so i just jumped in my car went down to the bypass put it in 3rd gear revved to 5 to 6 thousand revs let it decelerate to 3 thousand revs thereabouts, then booted back up then let it do the same again ect ect started at 6.20 pm light went off 6.42 pm i am going to be doing this evey time it comes back on now. F**K the GPF Lol :p
 
#42 ·
Hi Guys, I am new to this so wondering if anyone has taken this up with KIA and what the response is. I have had my Sportage 3, petrol, manual, for 3 months and done 2K miles - mostly urban. The warning light is now on and after 60 miles still on. The MPG has dropped by about 20%. Since the filter is fitted to reduce pollution and the remedy is to burn fuel which increases pollution are these filters fit for purpose? Anyone tried this on KIA?
Joe4597
 
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