1.5 tsi, any progress?

[Tester01]

There is an 2018 1.5 150 Troc in my family which I have driven a few times. I know not a Leon - but same engine.
Generally drove nice - feeling smooth, quiet and nippy.
Did a little hiccup when cold for me when first pulling away - but as I was not familiar with the car/clutch I wasn't too concerned, and the owner used to say it would hiccup/kangaroo when cold sometimes - but I think they have now learnt it's 'quirk' and drive around it - generally not being too gentle when on a cold start.

In my humble - this is due to the tuning and trying to get very quick warm up of the CAT for reduced cold start emissions - and as VW have had their fingers burnt with emissions, and this is how is has been homologated they won't be putting out any meaningful ECU fix.
I would think if kangarooing is an issue which can't be 'driven around' then a remap would help.

What’s the fuel like on that T Roc?

Still having crap mpg with mine, I think only solution for me is hoping a remap improves things.

But regarding mine is lumpy in the mornings I notice I’ve had the ECU for DADA, not as bad as it used to be pre update. Definitely not cured though.

 

[SuperV8]

What’s the fuel like on that T Roc?

Still having crap mpg with mine, I think only solution for me is hoping a remap improves things.

But regarding mine is lumpy in the mornings I notice I’ve had the ECU for DADA, not as bad as it used to be pre update. Definitely not cured though.

I think generally low 40's when putting about - and rises to 47-48 when on a motorway run.

I think in your position I would be seriously thinking of a re-map from one of the reputable tuners.

 

[Tester01]

I think generally low 40's when putting about - and rises to 47-48 when on a motorway run.

I think in your position I would be seriously thinking of a re-map from one of the reputable tuners.

Yeah only “solution” I see here.

Can’t remember if I mentioned it but back in June/July went back to dealer about the fuel issue. And said they can keeep it as long as they need to figure it out and feel free to drive it home etc - Even offered to pay for the fuel if necessary.

Apparently the lead technician guy managed to 45mpg in Eco mode on a 5mile journey…
Not that that’s impressive especially in reference to your T Roc on a run.

I personally think all he did was drive the car warm the engine up and then reset the overview mid journey. Drove a few miles and got a decent mpg and took a photo.

I mean I could do the same and get “amazing” mpg but it’s not reflective of a true report.

As im still yet to replicate such figures consistently, just did a 30 mile trip down the motorway before 34mpg…..

Think they did it to fob me off seeing as they’re probably sick of me booking it in.

Not convinced at all seems hood winking unless I’m doing something terribly wrong.

just wish I knew what the problem is seems nobody can provide a concrete answer as it’s definitely not right that I’m averaging 30mpg in a 150bhp Seat Leon.

If only I realised sooner hate that I’m so hung up on fuel economy but somethings just not right here.

 

[G.P]

What’s the fuel like on that T Roc?

Still having crap mpg with mine, I think only solution for me is hoping a remap improves things.

But regarding mine is lumpy in the mornings I notice I’ve had the ECU for DADA, not as bad as it used to be pre update. Definitely not cured though.

I can't be much help with MPG as since owning mine I've only relied on the infotainment read out and never worked out my MPG manually like I used to per fill, but my display varies between 38-55 MPG on different journeys.

 

[DEAN0]

just wish I knew what the problem is seems nobody can provide a concrete answer as it’s definitely not right that I’m averaging 30mpg in a 150bhp Seat Leon.

Agree - something seems off.

300hp Cupra - typical weekly mpg around 35
Good motorway run ( 70mph whenever possible ) - typically around 40

 

[Tester01]

I can't be much help with MPG as since owning mine I've only relied on the infotainment read out and never worked out my MPG manually like I used to per fill, but my display varies between 38-55 MPG on different journeys.

I’ve worked it out manually on my Leon in the past and it’s very similar to the trip computer, so concerns there regarding accuracy.

But your T Rocs defo better and SuperV8s is definitely much better than mine.

I’ve never seen 55 on a journey ever even on a long motorway trip.

Just so frustrating, no fault codes.

Don’t know what else I could check or try changing at home.

Truly baffling no matter what Seat tells me there’s definitely “nothing wrong” and it’s not “normal”

Has to be something that’s causing it

Agree - something seems off.

300hp Cupra - typical weekly mpg around 35
Good motorway run ( 70mph whenever possible ) - typically around 40

Yeah I’ve spoken to cupra owners previously they adveraged better. Ofc it’s never going to be like for like and directly comparable due to a number of factors but still.

Just stumped and stuck.

 

[Tester01]

Also random for any 1.5 TSI owners when opening your fuel cap do you get a hissing sound and like pressure release, noticed this for a while

When searching online getting mixed response as to whether it’s normal for cars.

I dunno if this could be having any impact on fuel economy

And if anyone has any suggestions of things to check re fuel feel free to throw them my way

 

[G.P]

Also random for any 1.5 TSI owners when opening your fuel cap do you get a hissing sound and like pressure release, noticed this for a while

Yes my Leon, Ibiza do this as does the Daughters KA..

 

[Tester01]

Yes my Leon, Ibiza do this as does the Daughters KA..

Thanks mate…

Really stumped what it could be.
Threw some fuel system cleaner in for the 100x time earlier this week no difference as expected

Wanna ask Seat to take a look again but chances are they’re just gonna scan the car which I can do at home and says there’s no faults

 

[Tester01]

Months on still no joy with finding cause.

Getting serviced this week.

Think maybe time to just get rid.

Getting 250-300 miles per tank is absolute pathetic somethings not right but no fault codes
Still averaging 30~ mpg even on a long run.

 

[decker53]

Also random for any 1.5 TSI owners when opening your fuel cap do you get a hissing sound and like pressure release, noticed this for a while

When searching online getting mixed response as to whether it’s normal for cars.

I dunno if this could be having any impact on fuel economy

And if anyone has any suggestions of things to check re fuel feel free to throw them my way

I get this every time I open the fuel cap to fill up

 

[Mr Pig]

Months on still no joy with finding cause.

Getting serviced this week.

Think maybe time to just get rid.

Getting 250-300 miles per tank is absolute pathetic somethings not right but no fault codes
Still averaging 30~ mpg even on a long run.

Yes, that's terrible. I would be thinking about getting rid of the car too. your MPG is terrible. My 150hp 1.4tsi gets between 40 and 50 mpg all the time. Usually around 45.

The hiss when you open the filler cap is normal incidentally.

 

[Tester01]

Yes, that's terrible. I would be thinking about getting rid of the car too. your MPG is terrible. My 150hp 1.4tsi gets between 40 and 50 mpg all the time. Usually around 45.

The hiss when you open the filler cap is normal incidentally.

Yeah honestly resent car and due to no answers it’s becoming more annoying the more I think about it.

wish I got the 1.4 they seem so robust.
Sick of being told mpg is “normal” as no issue as there’s no fault codes.

I have never seen 50mpg lol
Unless I reset the since start data mid drive lol

On another note

I’m now suspecting I may have a coolant flow issue, that’s been going on for a while.
That I forgot about and recently picked back up tracking.

no fault codes but noticed coolant temperature at radiator outlet never reaches anywhere near the specified value or other colant sensor temps

 

[Mr Pig]

Yeah honestly resent car and due to no answers it’s becoming more annoying the more I think about it.

wish I got the 1.4 they seem so robust.
Sick of being told mpg is “normal” as no issue as there’s no fault codes.

I have never seen 50mpg lol
Unless I reset the since start data mid drive lol

On another note

I’m now suspecting I may have a coolant flow issue, that’s been going on for a while.
That I forgot about and recently picked back up tracking.

no fault codes but noticed coolant temperature at radiator outlet never reaches anywhere near the specified value or other colant sensor temps

I track my mpg religiously, actually working it out for each tank, and my normal is about 46. I've got over 50 a few times and only three or four dropped below 40 to high 30s. You can't trust the car, you need to work it out. Fill the tank, reset the trip and when you come to fill the next time use the miles and liters you put in to work out the exact mpg you got out of that tank. It's very easy.

I don't know if a coolant would cause poor mpg but I imagine it could cause all sorts of issues. Have you checked your silicone bag? I removed them from our cars. I think the 1.5 is probably just as good as the 1.4 but it's being hobbled by the way it's being managed. Mechanically, it's probably just as good an engine. My daughter has one in an Ateca with an auto gearbox and it's fine.

 

[Tester01]

I track my mpg religiously, actually working it out for each tank, and my normal is about 46. I've got over 50 a few times and only three or four dropped below 40 to high 30s. You can't trust the car, you need to work it out. Fill the tank, reset the trip and when you come to fill the next time use the miles and liters you put in to work out the exact mpg you got out of that tank. It's very easy.

I don't know if a coolant would cause poor mpg but I imagine it could cause all sorts of issues. Have you checked your silicone bag? I removed them from our cars. I think the 1.5 is probably just as good as the 1.4 but it's being hobbled by the way it's being managed. Mechanically, it's probably just as good an engine. My daughter has one in an Ateca with an auto gearbox and it's fine.

been a while since I’ve manually tracked but recall doing it over a tank or 2 and the figures were similar to the computer.

Ill do it again on next fill up

 

[SuperV8]

On another note

I’m now suspecting I may have a coolant flow issue, that’s been going on for a while.
That I forgot about and recently picked back up tracking.

no fault codes but noticed coolant temperature at radiator outlet never reaches anywhere near the specified value or other colant sensor temps

This seems weird/wrong.
Coolant/temp issue could absolutely cause crap MPG.
I would check your temp sensors/wiring and check your thermostat.
Can you log your engine temp over a drive?

 

[SuperV8]

Found an exploded image of the 1.5tsi mechatronic thermostat/pump assembly:

 

[Mr Pig]

Found an exploded image of the 1.5tsi mechatronic thermostat/pump assembly:

Is that the same as the 1.4? So much plastic.

 

[Tester01]

This seems weird/wrong.
Coolant/temp issue could absolutely cause crap MPG.
I would check your temp sensors/wiring and check your thermostat.
Can you log your engine temp over a drive?

Will track it later today.
When you say engine temp do you mean coolant temperatures or another sensor readings should be looking at

From memory when driving when I’ve last looked at coolant temps using obd I’ve seen it in the 90s go up to 110.

Just the radiator outlet temp always looks way out of wack in comparison and maybe why I’ve not heard the fans in a long time.

Funnily enough I had a mechanic out in January one of those mobile ones to see if they could shed any light on why fuels so poor.

It was a snowy day so outside temp was 2c. He plugged his diagnostic tool in and started the engine and within less than minute, coolant temps was showing at around 29c.

Which he said was suspicious and thought based on that one of the sensors could be giving false readings.

Would you agree with that being odd? I’d imagine the coolant temp would’ve been same as outside temp initially?

 

[SuperV8]

Is that the same as the 1.4? So much plastic.

I think the 1.4 uses 2x conventional (wax/mechanical) thermostats, but in a similar housing on the end of the head.
The 1.5 is using that stepper motor to rotate the drum to vary the coolant path depending on ECU demand.