2017 Smart FourTwo Passion Premium 1.0L - Petrol leak

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Tue 3 Jan 2023 17:15
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - JK60
I purchased this 1L petrol car in the summer as a runaround with the intention of reducing costs but it feels anything but economical!
I’m noticing a strong smell of petrol on startup and my mpg is about 50 which I achieved by driving carefully and mostly doing 56mph where possible!
I have a years warranty and took it back on 2 occasions where they’ve even checked emissions but they cannot identify a problem!
Anyone else experienced similar problems or have any ideas please!
Thanks in advance
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Tue 3 Jan 2023 18:34
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - FP

A smell of petrol when starting from cold is almost inevitable. However, the thread title is "petrol leak", which is another matter. What evidence do you have of an actual leak? Can you smell petrol at times other than starting?

Real-life mpg of around 50 mpg doesn't sound too bad.

Edited by FP on 03/01/2023 at 18:37

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Tue 3 Jan 2023 18:46
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - Adampr

I agree, 50mpg sounds about right. Have you checked that the engine bay cover (under the boot carpet) is fixed in place properly?

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Wed 4 Jan 2023 08:13
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - JK60
Will check the engine bay cover but thought the garage would have done so on both occasions I revisited but still disconcerting that a cover needed to mask a possible leak
I’m an oldish guy now who used to tinker a lot with Minis back in the late 70’s and still have a bit of savvy but never experienced such strong smell of petrol apart from having flooded a carburettor back in the day !
Just seems very unusual but the garage seems to dismiss that there is any problem!
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Wed 4 Jan 2023 08:02
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - JK60
Thanks for your reply??
I have no proof that there is a leak but the fact that the strong smell indicates a leak to me coupled with the below mpg figures! I generally only notice smell on initial start up and lately on subsequent restarts. A mate mentioned it could be a cold start injector problem so just seeing if this could be a possibility …. or maybe something else?
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Wed 4 Jan 2023 09:07
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - elekie&a/c doctor
I’m sure if there was a leak you’d see evidence on the ground. It’s possible the fuel smell is from the fuel tank evap system pipe work. Also is the correct fuel cap fitted and sealed correctly. Btw , cold start injectors haven’t been used for around 30 years .
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Wed 4 Jan 2023 10:16
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - Andrew-T
It’s possible the fuel smell is from the fuel tank evap system pipe work. Also is the correct fuel cap fitted and sealed correctly. Btw , cold start injectors haven’t been used for around 30 years .

Back in the 90s I ran a Fiat Punto for a while - well-designed car, quite nice to drive, comfortable and economical. But one of its quirks was a noticeable smell of petrol if the sunroof was open. Clearly a gentle suction problem, never sorted it out.

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Wed 4 Jan 2023 09:19
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - Big John

If you look at car real mpg figures on this site then 50mpg seems reasonable. You don't mention driving type - ie urban, motorway etc. Is your car manual or auto?

www.honestjohn.co.uk/realmpg/smart/fortwo-2014

Re strong smell of fuel on safety grounds you should get this checked but it's usual for some unburnt fuel to come out of the exhaust pipe on first start up especially cold - petrol injected on initially turning the car over before it fires into life. With a Fortwo it's tiny so you are close to the exhaust pipe.

Edited by Big John on 04/01/2023 at 09:20

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Fri 6 Jan 2023 10:56
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - JK60

Thanks Big John!

It’s a manual petrol where over a 3 month period I achieved approx 50 mpg doing a mixed range of driving (mostly 30 mile trips) but to a maximum of 56 mph which I gather is the optimum speed to achieve the best figures!?

People have mentioned a leak would be evident which the garage assures me isn’t the case but that was during the very warm summer/autumn when it would probably evaporate than leave a pool of petrol so I’d imagine it’s a small leak if any!
As the smell gets more evident of late, I’m also noticing a hesitance in power when trying to accelerate…especially after starting from cold!

You’re right in saying that the engine is in close proximity to driver so it will be more noticeable but the fumes are really strong so either my nose is over sensitive or the garage mechanics are nose blind!
Whilst I’m trying to achieve the economic benefits, like you I’m also concerned at the safety issue but having taken it back twice I don’t know what else to do!?
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Fri 6 Jan 2023 12:15
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - Andrew-T

I would assume the fumes are being drawn in via the 'fresh-air' intake vents. What happens if you switch to Recirculate ?

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Sun 8 Jan 2023 11:56
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - JK60
No trace on recirculate!
I only notice the strong smell as I say on start up because I have to open/close my gate so it’s so noticeable!
Lucky I don’t smoke! ??
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Sun 8 Jan 2023 12:47
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - FP

"I only notice the strong smell as I say on start up because I have to open/close my gate so it’s so noticeable! Lucky I don’t smoke! ??"

The petrol smell on start-up is because the engine needs a richer mixture when cold, some of which ends up unburnt in the exhaust. No doubt you walk past your tailpipe when you open the gate.

In reality there isn't any fire risk.

We still haven't established whether there is any actual fuel leak, but after all that's been posted I doubt it.

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Sun 8 Jan 2023 15:02
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - Andrew-T

The petrol smell on start-up is because the engine needs a richer mixture when cold, some of which ends up unburnt in the exhaust. No doubt you walk past your tailpipe when you open the gate.

Surely we aren't discussing a petrol smell outside the car ? That would hardly be a 'problem' and would in any case be only temporary. Hence my query about Recirculate.

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Sun 8 Jan 2023 17:21
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - FP

"Surely we aren't discussing a petrol smell outside the car ?"

I think we are.

Q by Andrew-T: "I would assume the fumes are being drawn in via the 'fresh-air' intake vents. What happens if you switch to Recirculate ?"

A by OP: "No trace on recirculate! I only notice the strong smell as I say on start up because I have to open/close my gate so it’s so noticeable!"

So he doesn't get the smell when ventilation is on Recirculate and he notices it when outside the car.

Edited by FP on 08/01/2023 at 17:23

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Mon 9 Jan 2023 23:18
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - JK60
With respect, I have owned many cars in my 40+ years driving and at no time have I experienced fumes this strong which is evident on the outside of the car not inside!
It appears that I’m reaching a dead end with this unless someone knows otherwise!
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Mon 9 Jan 2023 23:39
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - Adampr

You don't have a leak, but it may be that your engine is running rich. Has the garage checked diagnostic codes?

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Wed 11 Jan 2023 22:48
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - JK60
Yes they’ve done emission tests and found to be normal !
Anyone else got any ideas ?
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Wed 11 Jan 2023 22:56
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - elekie&a/c doctor

Yes ,sell it and buy something sensible. Remember, the only thing "Smart " about these , is the badge .

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Wed 11 Jan 2023 23:20
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - Adampr
Yes they’ve done emission tests and found to be normal ! Anyone else got any ideas ?

If there are no fault codes the emissions are fine, the fuel's not going anywhere, it doesn't smell inside the car and it only smells outside the car when first starting from cold, ignore it.

If you really want to get to the bottom of it and are anywhere near Bristol / Somerset, call Richard at the Smart Workshop on 01934 833334 and he can take a look or, indeed, tell you that they all stink. In fact, he can probably do the second down the phone.

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Thu 12 Jan 2023 06:09
2017 Smart FourTwo Passion Premium 1.0L - Petrol leak - paul 1963

.......And if your anywhere near Guildford there's a smart car specialist on the slyfield industrial estate.

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