GPF Filter linked to poor fuel consumption?

[wbt]

Hi everyone,
After about 4 weeks of owning a Tuscon 2022 mild hybrid my GPF filter has come on, I can't quite be certain if its a coincidence or not but I seem to be doing rubbish with my fuel consumption...I drive approx 10 miles to work, approx 5 minutes at 70mph, 5 minutes at 50mph and 10 minutes at 30mph and its costing me around 15 miles of fuel.

I'm not a lead footed driver and the car is in Eco Mode, is this just "one of those things" or is it something more sinister?

Thanks in advance.

P.S booked in at the garage to clear my GPF filter.

[daibill]

I haven't had the GPF light come on myself but take a look at this

https://www.hypermiler.co.uk/gasoline-p ... ning-error

[XADE]

Yes the car runs 'lean' until it clears the gpf, which means you'll get worse economy.

I've had mine cleared by a dealership, and cleared it twice more myself in 18 months.

[wbt]

Great thanks, you’ve cleared it twice yourself…following the instructions above?

Thanks!

[Toucan]

I've had my Tucson for twelve months, the GPF light has not come on but the fuel economy has been worse over the last couple of months, and not just the effects of colder weather. Today I went on a motorway trip that I would have expected high 40s MPG from, but the car struggled to just about average 40mpg by half distance. Thinking that this could be connected to the GPF I dropped a couple of gears and gave it a good blast in fourth, accelerating and then letting the car drop speed, then repeated a few times before coming off the motorway for a break. On the second half of the journey the car averaged an indicated 56mpg, the traffic was a little lighter but I believe it just needed a good clear out after a few months of light low rpm running and some cold short journeys.

[XADE]

Great thanks, you’ve cleared it twice yourself…following the instructions above?

Thanks!

Yeah pretty much, I have a decent loop stretch of road where it takes 5-10mins to warm up, then 15mins of the above to clear it. It's worked twice for me.

Even better (I think) is if you have a hilly area where you can accelerate down a hill, and roll up in a lower gear to naturally slow the car. It probably doesn't make THAT much difference, but that's worked for me.

[swanseadavid]

My Tuscon is only 4 months old with just over 2000 miles and I have just noticed a dramatic reduction in my fuel consumption again with no GPF warning light.
I will try your fix and see if any change otherwise dealer to resolve.

2023 1.6 Ultimate in teal

[Robbit]

My Tuscon is only 4 months old with just over 2000 miles and I have just noticed a dramatic reduction in my fuel consumption again with no GPF warning light.
I will try your fix and see if any change otherwise dealer to resolve.

2023 1.6 Ultimate in teal

Interesting. My car is the same age as yours. I was averaging around 39-40 MPG on rural roads. I then had to go into the depths of despair (London) and found during the following weeks I was struggling to get 30-32 MPG.

No GPF warning on the dash at any point.

Last month, I covered around 400 motorway miles, since then 46-48 MPG.

So I bet we have the new software that delays the GPF cluster light. The car runs lean before the light shows (just a theory).

[PhilHornby]

the car runs 'lean' until it clears the gpf, which means you'll get worse economy.

Why would running lean result in worse economy?

I could well believe that an engine with, effectively, a blockage in its exhaust system would not be running at peak efficiency

[Robbit]

the car runs 'lean' until it clears the gpf, which means you'll get worse economy.

Why would running lean result in worse economy?

I could well believe that an engine with, effectively, a blockage in its exhaust system would not be running at peak efficiency

A complex conundrum. Engines with a leaner fuel to air mixture will indeed run hotter and use less fuel.

However, I ‘think’ Hyundai advance the timing for earlier ignition to achieve a leaner mixture. The downside of this is pre-combustion knocking (good old pinking) which can damage the engine and cause an increase in MPG. I have a feeling this change in mixture is very short lived before the car requires regeneration via CAN Bus.

As I understand it, the changes Hyundai made to reduce the GPF issue was to delay the GPF warning icon whilst simultaneously advancing the timing. In many cases this would clear the filter without the driver being aware, the downside is it does decrease MPG as noted above.

Its smoke and mirrors, the physical mechanics are still the same, the filter is still sooting up as before, but the warning comes on later, so drivers are not complaining that the filter has gone on strike.