Technical Help!!! fuel consumption problem

[Elihani]

iam facing one to the most annoying problem concerning my fiat punto HGT model 2002...
well ,its consuming too much gas above the average let say...
i have done my research indeed and i've cleaned my air filter,,,new spark plugs and new belt motor...
i was wondering if someone can advise me about what to do regarding this issue. i've read that his could be a symptom of oxygen sensor but the scanner shows no fault!!!
Any help is really appreciated
Cheers

 

[benny279]

Whats your average MPG? Also fuel consumption is based on more than one factor such as for example righty foot, tyre pressures, road conditions etc. Also what engine size have you got? But guessing by a HGT it'd be a sort of bigger engine than 1.2 so fuel will be consumed a bit more than a 1.2.....

This probably won't help but as I said fuel consumption is based on many factors so never point at one thing. Believe me I've had same issue before filled up next minute i found myself at a petrol station again

Just try do eco-driving for a bit and see if it improves.

 

[Ziggy122]

if the airfilter is clean and new that thats eliminated

To test lamba's you can wait years for a fault code to appear
OR
get something like Fiat Ecu Scan (Multi-ecu scan) and watch the voltages
The Pre cat sensor should peak and trough,
And the Post cat IIRC should remain fairly stable showing the cat is working

if either lamba's decides to die but not enough the car picks up on it - then your fuel consumption will shoot up

So get the voltages checked

Also - consider using a website called Fuelly - Fill up - put your details in and see where you stand with real life consumption

Ziggy

 

[Elihani]

its a 1.8 L 16V engines ,,,exactly its bigger than the ordinary engine ...
i know many factors are in charge of his process but as far as i can remember ,,,last year i had no such problem of this type ,,,so believe its an ecu issue
thx for ur opinion

 

[Ziggy122]

its a 1.8 L 16V engines ,,,exactly its bigger than the ordinary engine ...
i know many factors are in charge of his process but as far as i can remember ,,,last year i had no such problem of this type ,,,so believe its an ecu issue
thx for ur opinion

Dont blame the ECU untill your 100% sure

It could be forwell the lamba's are playing up themselves

Ziggy

 

[Elihani]

if the airfilter is clean and new that thats eliminated

To test lamba's you can wait years for a fault code to appear
OR
get something like Fiat Ecu Scan (Multi-ecu scan) and watch the voltages
The Pre cat sensor should peak and trough,
And the Post cat IIRC should remain fairly stable showing the cat is working

if either lamba's decides to die but not enough the car picks up on it - then your fuel consumption will shoot up

So get the voltages checked

Also - consider using a website called Fuelly - Fill up - put your details in and see where you stand with real life consumption

Ziggy

lets assume its an ecu problem ,,, could the ecu fault increase the consumption by 140 Kilometers per gallon???
can u provide me with more info regarding the fiat ecu scan?

 

[s and b]

sticky brakes would be my first assumption
followed by possibly a slipping clutch/diaphragm

think of the ecu as your own heart
ie if it goes on the blink you would get tale tale signs like skippy bunny jumpy and difficulty in starties occasionally
put fiatecuscan into google for linky to doing your own live data details

 

[benny279]

I'd agree with Ziggy on this it could well be your lambda's playing up, also for the fiat ecu scan you can download it by google searching multi ecu scan you can use the free version to check most things all you'll need is the vag-com diagnostic cable pretty cheap as well. This will help you determine if it is a lambda or ecu issue, or see if theres any problems there that may be causing your fuel consumption issue.

 

[s and b]

I'd agree with Ziggy on this it could well be your lambda's playing up, also for the fiat ecu scan you can download it by google searching multi ecu scan you can use the free version to check most things all you'll need is the vag-com diagnostic cable pretty cheap as well. This will help you determine if it is a lambda or ecu issue, or see if theres any problems there that may be causing your fuel consumption issue.

elm for injun diagnostics
rare for lambda not to put the light on by the way
obviously a quick solution would be an exhaust gas analyis

 

[benny279]

elm for injun diagnostics
rare for lambda not to put the light on by the way
obviously a quick solution would be an exhaust gas analyis

Yeah but you can use the vag-com to get live data off the car or clear engine ecu codes as I used this a while back as soon as I got a laptop and the cable

But yes I also agree with the exhaust gas analysis.

 

[s and b]

Yeah but you can use the vag-com to get live data off the car or clear engine ecu codes as I used this a while back as soon as I got a laptop and the cable

But yes I also agree with the exhaust gas analysis.

ive only found the blue cable suitable for doing airbags in conjunction with the red lead

 

[benny279]

ive only found the blue cable suitable for doing airbags in conjunction with the red lead

Mind you I was only using the free version of FES at the time But the blue cable came in handy about a month or so ago when I did my very first scan on the car, and came across a VSS error cleared it never returned. Now you've reminded me I have to get hold of the airbag cable to run a diagnostic on it, never had the airbag light on my Punto

 

[fingers99]

No ECU light would point me to look outside the engine first -- brakes, etc.

The ECU on the HGT doesn't appear to have a high fail rate by any standards.

 

[Ziggy122]

i agree never hear a hgt ecu failure

since hgt has rear disc check.the hanbrake to it is releasing and the front wheels spin easily


ziggy

 

[PuntoHowTo]

When you say above average fuel use what is the actual fuel use? The 1.8 is a fairly thirsty engine anyway, but what are you getting MPG, Km/L ?

Without knowing how bad the issue is its very hard to say what the problem is 140Km per gallon I calculate to be 84mpg which would make it the most fuel efficient punto ever so I suspect you got this wrong. Could be something as simple as a stuck thermostat

Much more information needed I think

 

[benny279]

When you say above average fuel use what is the actual fuel use? The 1.8 is a fairly thirsty engine anyway, but what are you getting MPG, Km/L ?

Without knowing how bad the issue is its very hard to say what the problem is 140Km per gallon I calculate to be 84mpg which would make it the most fuel efficient punto ever so I suspect you got this wrong. Could be something as simple as a stuck thermostat

Much more information needed I think

Mine gets on average on a motorway run around 60-72mpg although yes it's a 1.2 engine but still good MPG I suspect a 1.8 to be around 40-50?

 

[PuntoHowTo]

Mine gets on average on a motorway run around 60-72mpg although yes it's a 1.2 engine but still good MPG I suspect a 1.8 to be around 40-50?

I'm gonna guess you're talking instantaneous figures off the dash rather than an average accurate fuel consumption the 1.2 combined official figure is 49.6mpg so a very long way off 60-72mpg and extra urban (ie motorway driving) is still less than 60mpg

The 1.8hgt combined fuel consumption is 34mpg which isn't as good as some bigger heavier cars with similar sized engines.

That aside would be fare more interested to know what the OPs fuel consumption actuall is

 

[benny279]

I'm gonna guess you're talking instantaneous figures off the dash rather than an average accurate fuel consumption the 1.2 combined official figure is 49.6mpg so a very long way off 60-72mpg and extra urban (ie motorway driving) is still less than 60mpg

The 1.8hgt combined fuel consumption is 34mpg which isn't as good as some bigger heavier cars with similar sized engines.

That aside would be fare more interested to know what the OPs fuel consumption actuall is

Maybe so but hardly anyone goes by those stated figures that Fiat say, well I certainly don't when my car does the stated figures (official) I don't get much for my money with the dash telling me I'm doing above average I get more for my money as in around 55mpg at one point travelling from where I live to London.

 

[Elihani]

When you say above average fuel use what is the actual fuel use? The 1.8 is a fairly thirsty engine anyway, but what are you getting MPG, Km/L ?

Without knowing how bad the issue is its very hard to say what the problem is 140Km per gallon I calculate to be 84mpg which would make it the most fuel efficient punto ever so I suspect you got this wrong. Could be something as simple as a stuck thermostat

Much more information needed I think

as u said ,,,if my car consumes 84mpg ill be the happiest man on the planet but ,,,i used to have a fair fuel consumption until 2 months ago i started to feel some kind weird ,,,
could it be an oxygen sensor failure???
a Lambda up high score???
ill provide u more infos later on after registering to fuelly.com

 

[Ziggy122]

as u said ,,,if my car consumes 84mpg ill be the happiest man on the planet but ,,,i used to have a fair fuel consumption until 2 months ago i started to feel some kind weird ,,,
could it be an oxygen sensor failure???
a Lambda up high score???
ill provide u more infos later on after registering to fuelly.com

Lambas need a series of runs to get a true view of what there doing
If there flat lining and the ecu hasn't picked it up - check the wiring

Fuelly is a great way to show a long life mpg, as you can see from mine - i drive terrible, because i do no end of short runs (1 or 2miles)
All day everyday

Ziggy