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Focus 2008 Mk2 1.8 Duratec He Petrol Poor Mileage


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Hi

Im new member here and have the common problem with my 2008 focus 1.8 duratec HE petrol engine, its poor mileage.

First i bought this car its done 17MPG on urban driving and thats painful. I've been searching on the web and found that i should check on air filter, plugs, oils. So i changed all in the list and still get the same 17MPG (i use Shell v-power). Then i realize the temp gauge is not achieve in the middle so i assumed the engine was too cold and the fan is kickin from the beginning of the engine starts. But when i checked on the lcd secret menu, the temp is 70C on cold and 137C when its hot so thats mean something wrong on the gauge or the temp sensor. I changed the temp sensor and the gauge is rising to the middle and fans kicks on around 125C. Im not resetting the ecu and i've got 25MPG but with speedo gauge dead (after i changed temp sensor).

So i decided to reset the ecu and i've got 3 codes and erase them, and voila... Mileage is back to 17MPG. Im not sure whats wrong here but maybe someone can help me fix this because it was painful to have 17MPG from a 1.8 car. My buddy here drive a 2.0 focus and he get 25MPG so thats causing me to keep searching whats wrong with my car.

Thanks

Jap

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OK. Obvious question... What were the error codes?! Might be a clue there. Also, 125c seems a bit high to me...

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By the way, I got 43mpg out of a full tank last month from my petrol 1.8 so there's something fairly wrong with your friends car as well... Or his driving

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1 - Are you sure your temps are not on Fahrenheit and not centigrade - 70 when cold and 137 when hot, and the fan coming on at 125, are very high if they are centigrade

2 - v-power is expensive, just use the cheapest pump / supermarket petrol you can find, you won't get better MPG but it will cost you less/ save you money because it is cheaper - it will not have as much detergent in it and the octane rating may be lower than v-power, but for most motorists - that won't matter but the money saving will

3 its not mileage, its MPG or miles per gallon - if you are asked what the milage is on a car they don't mean the MPG

4 - is the 17mpg what the computer reads or the actual MPG? - work out the actual MPG using traditional methods (eg brim-to brim or reset the mileometer to see how far you get on x amount of fuel ) (the speedo/ milometer would need to work to do this)

5 if the ECU "thinks" the engine is cold after it has warmed up, it may mess up the air/ fuel ratio - this is analagous to an old -style carburetted cars' automatic choke sticking closed and running rich

6 - if you are driving around town all day, sitting in traffic with the AC on and the engine running, then "booting" it in the lower gears, 17mpg may very well be what you are getting in those conditions, when top gear test a car, the MPG often drops at the test track, even a Toyota Prius only achieved 17,2mpg in ten laps, (being driven flat out) a BMW M3, following behind at the same speed as the Prius, achieved 19.4MPG, - so its not just what you drive but the way you drive it

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The digital dash temp is the head temp the dial is the coolant temp so youre wasting youre time with that one as its the way its meant to be the coolant is about 40 degrees cooler than the head so 137 means 97 degrees in coolant temp at 125 thats 85 which is too low so youve caused an issue by doing the sensor im afraid possibly an airlock or the coolants low

As for mpg having had a 1.8 urban mpg unless youre booting it every where you should at minimum get 28-32.

v power once in a while is okay not all the time thats a waste and wont gain you bhp ide suggest a decent garage has a look the fan

unless the aircon is set to windscreen it shouldnt be on from the start that will overcool the engine causing poor mpg it may have a faulty fan switch if so its likely severe overcooling is causing the low mpg

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Thanks for the replies. First thing is i dont remember the error codes but i remember one with "fuel" on it, lol

Yes i also tried traditional mpg count and the result is just a little bit different, like on the dash said 17MPG, the traditional way get 17.6MPG

@artscot79 : if you said overcooling, the temp gauge is now a little pass the midline when its hot so i guess it was a good running temp right?

Is there a chance the thermostat is also bad?

And i read somewhere that if you change the temp sensor uou should put a copper washer on the sensor so it will read correctly, anyone?

My guess is still temp problem but i dont get it where is it.

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Drove my focus today with medium traffic jam and lcd says 15MPG, this is the worst i've got after change the temp sensor, im starting to think i should sell this thing before it get me broke, but somehow im still curious what's wrong and how to fix it.

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OK, have you actually done what a poster said previously and measured the mpg accurately? You're not going to get any where near accurate results from the LCD unless you reset it anyway (hold down the set button when its displayed).

Also check that your brakes aren't binding. My front left was binding and it was causing my car to steer left and lower economy. I initially thought it was my tracking...

Also, these problems don't usually just manifest out of thin air without some kind of warning. Has the car always had poor economy? Anything look out of place from visual inspection under the bonnet? Any strange sounds? What mileage has the car done?

I'd also check and log sensor readings from your odb reader and check the values look sensible. Check your pre cat o2 sensor is operating correctly as well as this affects air fuel ratio.

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OK, have you actually done what a poster said previously and measured the mpg accurately? You're not going to get any where near accurate results from the LCD unless you reset it anyway (hold down the set button when its displayed).

Also check that your brakes aren't binding. My front left was binding and it was causing my car to steer left and lower economy. I initially thought it was my tracking...

Also, these problems don't usually just manifest out of thin air without some kind of warning. Has the car always had poor economy? Anything look out of place from visual inspection under the bonnet? Any strange sounds? What mileage has the car done?

I'd also check and log sensor readings from your odb reader and check the values look sensible. Check your pre cat o2 sensor is

operating correctly as well as this

affects air fuel ratio.

Yes i've done brim to brim way and i also reset the lcd. My car mileage is 35,000 miles and the engine sounds good from under the bonnet and yes it always have poor MPG since i bought it (maybe thats why the previous owner sells it).

I wanna check the value on obd but i dont know the standards, where i could find them?and the pre cat O2, how to check it?

Thanks

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When was it last serviced? it sounds to me like you have a few different issues which may be better after a service, my thoughts are:

1) Air filter may be dirty, as such its not taking in enough air to burn the fuel properly so the fuel is being wasted2

2) The mass air flow sensor is dirty, so its not recognising the right amount of air in the systerm, thus overfuelling

3) the Fuel filter may be dirty - contaminating the fuel and offering a poor MPG

4) if the oil and filter are in poor health, they are not lubricating the engine properly and your resulting in a bad health

5) Split air hose somewhere, means that air is going out and again causing overfuelling and poor burning

6) faulty or stuck EGR valve which is causing the recirculated air to be used more than it should reducing the efficiency and making the engine work harder.

17MPG is terrible at any time, but on an 08 plate, it shows there are going to be either one massive problem, or more likely plenty of little problems all making it much worse

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When was it last serviced? it sounds to me like you have a few different issues which may be better after a service, my thoughts are:

1) Air filter may be dirty, as such its not taking in enough air to burn the fuel properly so the fuel is being wasted2

Air filter is brand new, i changed it last month on service.

2) The mass air flow sensor is dirty, so its not recognising the right amount of air in the systerm, thus overfuelling

I serviced the car last month cleaning, here's the list of service i've done:

- air filter change

- battery change (varta)

- plugs change (motocraft)

- carbon clean

- transmission fluid change

3) the Fuel filter may be dirty - contaminating the fuel and offering a poor MPG

This type of engine doesnt have changeable fuel filter, its located inside the tank with the fuel pump

4) if the Oil and filter are in poor health, they are not lubricating the engine properly and your resulting in a bad health

Engine oil is changed on 33,000miles now the car is 35,000

5) Split air hose somewhere, means that air is going out and again causing overfuelling and poor burning

I havent check leaks, will do

6) faulty or stuck EGR valve which is causing the recirculated air to be used more than it should reducing the efficiency and making the engine work harder.

Where is the EGR valve located and if it fault how can it be fixed?

17MPG is terrible at any time, but on an 08 plate, it shows there are going to be either one massive problem, or more likely plenty of little problems all making it much worse

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I search the web and finds that EGR valve is only exist on diesel engine is that correct?

I am curious about the engine temp, previous post said it was engine coolant temp which is 40degrees higher than engine temp, so i check again on lcd hidden menu and it says "engine temperature" which is showing 121 C when its hot.

One more, if engine oil can make poor MPG, let say i wanna change the oil, what oil is recommended for duratec engine and what is the SAE if the oil should be use?

Thanks

Jap

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Make sure that the plugs are gapped correctly and that the leads are fitted fully.

Also make sure that the battery is silver calcium otherwise it will cause more trouble than not.

EGR I believe can also be fitted to the Petrol engines these days, I would suggest that you follow Lenny's guide in the guides section for fitting an EGR blanking plate to see if you can locate the EGR.

With regards the oil, I believe you need 5w30 Synthetic to get the best out of the car.

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Make sure that the plugs are gapped correctly and that the leads are fitted fully.

Also make sure that the battery is silver calcium otherwise it will cause more trouble than not.

EGR I believe can also be fitted to the Petrol engines these days, I would suggest that you follow Lenny's guide in the guides section for fitting an EGR blanking plate to see if you can locate the EGR.

With regards the oil, I believe you need 5w30 Synthetic to get the best out of the car.

I havent change the gap of the plugs, what is the best gap i should have?

Yes the battery is silver calcium

I will check out Lenny's guide about EGR and i will try to change the oil to make sure, thanks a lot

I'll post updates soon

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No worries, as for the gaps, I believe its documented as 1.3 but its best to have these at 1.0 for best running (I believe thats right and not the other way around!)

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No worries, as for the gaps, I believe its documented as 1.3 but its best to have these at 1.0 for best running (I believe thats right and not the other way around!)

Ok I'll check the gap also

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Ok here's a little update :

- i found out that this 08 duratec engine doesn't have MAF sensor, they use T-MAP sensor instead. I removed it with pain because of the location is very tricky to remove, carefully clean the round brass like tip with WD40 and cotton bud. The T-MAP sensor looks clean when I pulled it out (i've seen the gummy oily tip on the net)

- checked the plugs gap and its on 1mm straight so i guess that was correct gap

- the job took about one hour with battery unplugged so i thought this will reset the ECU

- running test the car and i've got better MPG (just from my feeling for watching the fuel gauge drops), lcd says 19.1 MPG but i also got less power at mid throttle than before. Lcd hidden menu still read engine temp 125C when blower kicks on.

Im thinking to change engine oil with fully synthetic 5W-30, i wonder what brand will be best for this engine?

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Motorcraft is the one you tend to find Ford use.

2mpg is an improvement I would be looking for another issue though

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Motorcraft is the one you tend to find Ford use.

2mpg is an improvement I would be looking for another issue though

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Yes i am still looking for another issue. I will try change the engine oil and filter.

And i've noticed that on the hidden menu, there is road speed, engine speed, odo count, which all have zero value is that normal?i only see a/d fuel, engine temp, RAFE, fuel flow, fuel percent that have values.

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depends if your standing still at the time your looking at it :p

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Update after driving the car, i again tried brim to brim and best is i only get 19.5 MPG. I am now wondering if i should try cleaning the EGR?will it be worth with the risk error appear on the car because i read there's hassle from cleaning the EGR so i have doubt to try it.

And i also read of updating ECU sensor will affect performance and fuel economy, is that possible?

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Wow, how is this still happening... did you check the brakes aren't binding? It sounds like you've checked most things, whether or not you checked them properly I don't know.

As for the o2 sensors... Torque is an Android app that has a "Test results" option to show you if the pre cat sensor is oscillating correctly.

Failing all of the above sounds like you need to take it to a garage. I can't believe 19.5mpg and it's cause would be that hard to spot, either visually or audibly.

Whereabouts are you? Have you had another better performing Focus to test against?

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Wow, how is this still happening... did you check the brakes aren't binding? It sounds like you've checked most things, whether or not you checked them properly I don't know.

As for the o2 sensors... Torque is an Android app that has a "Test results" option to show you if the pre cat sensor is oscillating correctly.

Failing all of the above sounds like you need to take it to a garage. I can't believe 19.5mpg and it's cause would be that hard to spot, either visually or audibly.

Whereabouts are you? Have you had another better performing Focus to test against?

I dont know what's wrong with the car since it already like that by the time i bought it. Brakes are good, no bindings.

The torque apps, i have to buy the OBD2 interface also right?the O2 checking is one of my curiosity lists, lol but the price of O2 sensor is not cheap.

Im in indonesia. There's several people here drive a 2.0 petrol focus mk2 (mine is 1.8) and they've got average 23-26 MPG so i envy them, they have more power with the 2.0 and better MPG.

I

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  • 7 years later...
On 7/14/2014 at 7:32 PM, fourspeed said:

I dont know what's wrong with the car since it already like that by the time i bought it. Brakes are good, no bindings.

The torque apps, i have to buy the OBD2 interface also right?the O2 checking is one of my curiosity lists, lol but the price of O2 sensor is not cheap.

Im in indonesia. There's several people here drive a 2.0 petrol focus mk2 (mine is 1.8) and they've got average 23-26 MPG so i envy them, they have more power with the 2.0 and better MPG.

I

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Did you ever manage to fix this issue as i have the exact same problem with my 1.8 petrol. Thanks 

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@Roo123 you do know that the original post is over 7 years old ?

The OP has not been back to the forum since November 2014, so I'm quite sure he's not going to answer you.

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