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Car mechanics/experts?

24
Found 15th Jul
my gf as a mark 2 1.6 petrol focus. it's mpg is shocking. 25mpg. she does very short trips under 2 miles. apart from changing car is there anything else than can be done to improve mpg. I've changed oil, filter, plugs etc. one thing I particularly want advice on is I'm currently using a 5w30 oil. would swapping to 0w30 help fuel economy or be so bad for engine? thanks in advance.
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Have you checked for a fuel leak? Either from the tank or lines?
Regular short trips will give the worst mpg - the engine is at is most efficient when at optimum temperature.
Maybe it’s a combination of the above and her driving style?
ktm66610 m ago

Have you checked for a fuel leak? Either from the tank or lines? Regular …Have you checked for a fuel leak? Either from the tank or lines? Regular short trips will give the worst mpg - the engine is at is most efficient when at optimum temperature. Maybe it’s a combination of the above and her driving style?


No fuel leaks. She's drives like miss daisy. I've noticed though when checking it with an obd scan tool the fuel trims are negative 8
That sounds about right the urban mpg figure for that car is around 27mpg, as she is doing very short journeys the car isn't getting up to the optimal operating temperature. As you have a OBD scanner scan the car for faults and report back any fault codes present.
Manual or auto? Mrs has an auto 1.6 focus and that returned under 30mpg (short journeys)
Edited by: "u664541" 15th Jul
Sprograt10 m ago

That sounds about right the urban mpg figure for that car is around 27mpg, …That sounds about right the urban mpg figure for that car is around 27mpg, as she is doing very short journeys the car isn't getting up to the optimal operating temperature. As you have a OBD scanner scan the car for faults and report back any fault codes present.


Yea I agree. This sounds about right. Maybe worth checking the tyre pressure? Could possibly get it a little bit higher with some economical driving as you should be able to get it near to the 30mpg
Sprograt22 m ago

That sounds about right the urban mpg figure for that car is around 27mpg, …That sounds about right the urban mpg figure for that car is around 27mpg, as she is doing very short journeys the car isn't getting up to the optimal operating temperature. As you have a OBD scanner scan the car for faults and report back any fault codes present.


No fault codes. Just the fuel trims should be around 0ish and the car is subtracting fuel -8. Always a petrol smell coming from the exhaust as well. Sounds wierd but true.
Checked tyre pressure and they're right.
Thanks for all the comments.
Anyone know if changing to 0w30 would help?
She might be driving like miss daisy but in the wrong gear. You want it In 5th as soon as possible. I'm regularly in 5th from about 20mph in Town. And on 30mph roads I'm always in 5th unless it's a big hill.

Changing the oil shouldn't make a noticeable difference. At least I never noticed anything on my car when I change oil between 5w and 0w.
I always find changing or gapping the plugs makes the biggest difference, but you already did that.
MonkeysUncle3 m ago

She might be driving like miss daisy but in the wrong gear. You want it In …She might be driving like miss daisy but in the wrong gear. You want it In 5th as soon as possible. I'm regularly in 5th from about 20mph in Town. And on 30mph roads I'm always in 5th unless it's a big hill. Changing the oil shouldn't make a noticeable difference. At least I never noticed anything on my car when I change oil between 5w and 0w.I always find changing or gapping the plugs makes the biggest difference, but you already did that.


There is them four point Bosch ones fitted. So no need to gap. I might try swapping with the ones you can gap.
Sounds about right, must be always on 'choke' at 2 miles, that might explain the petrol smell. Take it for a longer run and see if it still smells, if it does then further investigation may be needed.
Changing from a decent sparkplug anyway wouldn't make a difference. If its a constant fuel trim of - 8 there could be a chance a injector is leaking.
A minus shows its trying to lean the mixture where a plus means its richening the mixture.
Although is its not throwing a code so its within tolerances.
I have a Mk1 1.8L, get 20mpg, feel your pain.
dcx_badass1 m ago

I have a Mk1 1.8L, get 20mpg, feel your pain.


Lol
compadre6 m ago

Sounds about right, must be always on 'choke' at 2 miles, that might …Sounds about right, must be always on 'choke' at 2 miles, that might explain the petrol smell. Take it for a longer run and see if it still smells, if it does then further investigation may be needed.


Good idea
MonkeysUncle13 m ago

Changing from a decent sparkplug anyway wouldn't make a difference. If its …Changing from a decent sparkplug anyway wouldn't make a difference. If its a constant fuel trim of - 8 there could be a chance a injector is leaking. A minus shows its trying to lean the mixture where a plus means its richening the mixture.Although is its not throwing a code so its within tolerances.


That's my suspicion or the fuel pressure regulator. Just too scared to take in and have big bill.
Edited by: "Ayden1977" 15th Jul
Take it for a trip where it can get up to temperature and then see what fuel consumption you get at "normal driving conditions".

Unfair to comment on a car's mpg over such short distances. I would suspect everything is as it should be.
A shot of cataclean for petrol engines in the fuel might help a little.

If she’s doing short trips the engine isn’t getting hot enough to burn efficiently, so that’s probably why the economy sucks. An electric car would suit that type of driving well!
Edited by: "cmdr_elito" 15th Jul
cmdr_elito28 m ago

A shot of cataclean for petrol engines in the fuel might help a little. If …A shot of cataclean for petrol engines in the fuel might help a little. If she’s doing short trips the engine isn’t getting hot enough to burn efficiently, so that’s probably why the economy sucks. An electric car would suit that type of driving well!


Cheers will try that. Can't afford electric car at moment
A hybrid ?

I had a 1.6 MK2 and did an 8 mile 30/40mph stop start drive to work . Struggled to get above 27 mpg measured from brim to brim . To me sounds about right. Does the fuel economy increase when on a long / motorway run ?

Only thing that Might be worth it is taking it for an "Italian" tune up could get another 1/2mpg out of it. Just take it on the motorway and give it the beans through the first 3 gears then cruise at 70/75 in 4th for a bit .
muz3794 m ago

A hybrid ? I had a 1.6 MK2 and did an 8 mile 30/40mph stop start drive to …A hybrid ? I had a 1.6 MK2 and did an 8 mile 30/40mph stop start drive to work . Struggled to get above 27 mpg measured from brim to brim . To me sounds about right. Does the fuel economy increase when on a long / motorway run ? Only thing that Might be worth it is taking it for an "Italian" tune up could get another 1/2mpg out of it. Just take it on the motorway and give it the beans through the first 3 gears then cruise at 70/75 in 4th for a bit .


Yes it does increase slightly when on longer runs.
Need more info into what your 2 mile trip is.
Driving style, controlled acceleration or ragging the car, 20 mph streets or dual carriageways, stop starting or continuous driving.

Driving in first and second gear for 10 minutes in really heavy traffic gives me about 20mpg and going on a motorway in 6th gear for 10 minutes gives me about 55mpg. Nearly treble just because of how the car is being driven within that 10 minutes.

Have you tried resetting the mpg and driving on the motorway and then google the real average mpg of your make and model. Make sure it’s a real mpg and not an official one as they are always higher.
jayonline8511 m ago

Need more info into what your 2 mile trip is.Driving style, controlled …Need more info into what your 2 mile trip is.Driving style, controlled acceleration or ragging the car, 20 mph streets or dual carriageways, stop starting or continuous driving. Driving in first and second gear for 10 minutes in really heavy traffic gives me about 20mpg and going on a motorway in 6th gear for 10 minutes gives me about 55mpg. Nearly treble just because of how the car is being driven within that 10 minutes. Have you tried resetting the mpg and driving on the motorway and then google the real average mpg of your make and model. Make sure it’s a real mpg and not an official one as they are always higher.


Like he says. Even 1.0 engines can struggle to get 30odd mpg for short journeys.
Tbh 25mpg on short trips sounds about right. I Remember having a old 2.0 audi, I was lucky to get 20mpg on short journeys. I used to think 37mpg on a motorway run was doing well.
I’m no expert!
But experience is telling me -it’s a 1.6 Petrol plus Urban driving! And my missus has a lead foot and she’d give Hamilton a run of the lights!
I’ve had 1.1 / 1.4 / 1.4 1.25 petrol engines in that order and I’ve alway averaged 30-40 mpg urban but as soon as I hit the motorway and hit the seaside 40-50 the difference is crazy! And people that have had 1.6 petrol fords I know have always said there thirsty! Hence why most people now have like 1.1l ecoboosts but it terms of the question I have zero idea on that!
That's perfectly normal for short journeys. You can do things to help improve mpg like making sure the tyres are the correct pressures, service it, give it an Italian tune up but it won't make much difference.

Lamba sensors and faulty catalytic converters can cause incorrect fueling but it seems normal imo.

Constant short journeys will gum the pistons and shorten the oil lifespan along with the battery etc etc. but better than a diesel would be.

Thrash it to help clean the gum off the pistons occasionally.
You need to speak to JohnChappell. He's the self appointed HUKD expert on fuel trims and just about everything else mechanical. Maybe you already know him?
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