2004 1.4p MPG

Munkypuzzle

Munkypuzzle

Member
Afternoon folks,

Apologies if this is a repeated thread but after looking through quite a few, I can't seem to find something that is as near as to bad as mine. (Also please forgive me as I am not hugely mechanically minded, but I am learning as I go).

I've just bought an A2, its mint and I love it.........but the MPG is atrocious and I need some guidance on what to try next. I am currently getting about 20-22mpg which is half of what I see others talking about and I have no clue why it's so bad. I'm averaging 200/220miles to a tank (42ltr) and I use the correct 95fuel from my local BP garage. I do only do small runs for a few miles here and there and probably average about 300/500miles a month max. I know I do get slightly better MPG on a motorway run, but I think the best I have seen is 29MPG.

It's running 17inch tyres at the right pressure, and had new oil and filter at the last service but I have no clue as to why the MPG is so bad. I thought about the spark plugs maybe needing changing, but it seems to run and pull fine so I don't think that is a real issue.

Any pointers would be welcomed as I would love to have it running as sweet and frugal as possible.

Cheers

Neil
 
Hello,

Even if you only drive short, urban environments, you should definitely be achieving better than that.

Firstly, Have you calculated the MPG figures based on how much fuel you’ve actually put in it to fill the tank, as opposed to relying on DIS (if your car has that)? This is the only way to get a known-accurate figure as you may already be well aware.

Next step is two-fold:

1) give the thing a “birthday service”. Replace all fluids and filters, spark plugs and coil packs if not known-good (and especially if they are not original equipment / VAG, Bosch or NGK). Clean out the crankcase ventilation system.

2) I would scan the car for engine fault codes on VCDS - Check the members register elsewhere on the forum.

Once all that has been crossed off the list I would certainly feel confident that all is as it should be.

Someone else will be able to advise on other things to look for / check.

As a side note, I would definitely consider getting a set of smaller and lighter wheels on it. I’m biased but I do think pepper pots with 185/60/15 tyres are the ideal combination of looking OK, performing well and enabling a useful fuel efficiency increase just in themselves because they are so light.
 
What is the milleage on your A2? Does it use oil? Have ever lambda sensors been changed in the past?

Spark plugs change is always right thing to do ;)

Also 17" wheels will have some factor in the consumption, but definitely not that great. From my point of view 16" are just as fine looking and still have some rubber.
 
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Munkypuzzle said:
It's done 102k overall and yes I've calculated the MPG based on the miles driven over the 42ltr I put in the tank.
Click to expand...
Has it been scanned, with a VAG specific scan tool, to check on the health, or otherwise, of the engine? If not, then that should be done urgently.
There's obviously something wrong, and continuing to drive it, without knowing what, risks permanent damage.
All the suggestions are worth considering, also.
Mac.
 
Ok, thank you for all the advice, looks like I have some work to do, but glad I was right in thinking "there's definitely something wrong here"
 
The 1.4 petrol is the least fuel efficiency version of the A2, however as others have said it shouldn't be anywhere near as bad as you say.
I would personally check that the brakes aren't binding, particularly the rear drums and would jack the wheels up and spin them and see. Test them individually with the handbrake on and off which is also good to check that there isn't a braking imbalance over the rear axle and that both sides are working correctly as well as checking for binding which is common.
The second thing would be to check that the car is getting to 90° when up to temperature as it could be the temperature sender which is a common fault and causes the car to over fuel (a scan as recommended would be wise).
I would also check the condition of the tyres, the brand of them and reference how fuel efficient they are (you can search the tyre label online), check the tyres pressures are correct and finally (something that I thought to mention when I saw your first post but held back) check the condition of your wheels on the insides as although they look fabulous on the A2 and there is nothing at all wrong with them contrary to what some others say but because they wear low profile tyres which offer little give and because of the terrible state of our roads with pot holes everywhere they tend to pick up flat spots, sometimes many of them which cause them to go out of round and in some cases more square than round which obviously really effects the ride quality. Although not massively economy related it is definitely something I would check (on a wheel balancer if possible) but at least by jacking each wheel up (when you check the brakes) and look at the inside rims whilst spinning them as fast as you can. If you are lucky and they are still good avoid potholes like the Plague and you will be fine 😁

Good luck 👍

Edit- I just saw you already checked the tyre pressures what are you running front and rear?
 
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A2Z said:
The 1.4 petrol is the least fuel efficiency version of the A2, however as others have said it shouldn't be anywhere near as bad as you say.
I would personally check that the brakes aren't binding, particularly the rear drums and would jack the wheels up and spin them and see. Test them individually with the handbrake on and off which is also good to check that there isn't a braking imbalance over the rear axle and that both sides are working correctly as well as checking for binding which is common.
The second thing would be to check that the car is getting to 90° when up to temperature as it could be the temperature sender which is a common fault and causes the car to over fuel (a scan as recommended would be wise).
I would also check the condition of the tyres, the brand of them and reference how fuel efficient they are (you can search the tyre label online), check the tyres pressures are correct and finally (something that I thought to mention when I saw your first post but held back) check the condition of your wheels on the insides as although they look fabulous on the A2 and there is nothing at all wrong with them contrary to what some others say but because they wear low profile tyres which offer little give and because of the terrible state of our roads with pot holes everywhere they tend to pick up flat spots, sometimes many of them which cause them to go out of round and in some cases more square than round which obviously really effects the ride quality. Although not massively economy related it is definitely something I would check (on a wheel balancer if possible) but at least by jacking each wheel up (when you check the brakes) and look at the inside rims whilst spinning them as fast as you can. If you are lucky and they are still good avoid potholes like the Plague and you will be fine 😁

Good luck 👍

Edit- I just saw you already checked the tyre pressures what are you running front and rear?
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The engine temperature is very important, as it's the major influence on the ratio of fuel to air. If the engine isn't getting up to temp, or the ECU thinks it's not getting up to temperature, fuel consumption will be high. The temperature gauge in the dash is not a good indication of the engine temperature though ...
The dash may show that all is well, but because the dash gauge uses a different sensor to the ECU, actual engine temperature is known only to the ECU. So a failure of the engine temperature sensor, (not unknown by any means), goes undisclosed, that is until OBD diagnostics are used.
So, as well as a scan for faults, any OBD diagnostics should include checks of critical things like engine temperature.
Mac.
Edit:
In the same way, failure of the dash gauge sensor can, of course, lead to a unnecessary thermostat replacements. So, check the actual engine temperature, via the OBD port, before pic up your spanners, or credit card.
 
One of the most common thread subjects here concerns engines that are not reaching running temperature, usually based on the temperature "gauge" reading.
The thermostat is (nearly), always seen to be the culprit. And there are quite a few instances of the thermostat being changed two, or even three times, along with disparaging comments about the quality of thermostats.
Basing that amount of work, and expense, on a temperature gauge, which is not a gauge at all, (it's only an indicator), is, in my view, questionable.
The temperature indicator's relationship with the sensor it represents is ... vague. The temperature indicator is driven by an algorithm in the instrument controller, not by the sensor. The algorithm ensures the needle moves nice and smoothly, shows 90C when the coolant temperature is any in the "normal" range. No movement of the needle as the coolant temperatures varies with load, ambient conditions, thermostat opening and closing, etc, nice steady 90C.
More significantly to @Munkypuzzle the sensor the algorithm uses is completely separate from the coolant temperature sensor that the ECU uses to control the engine, and in particular relevance to mpg, the fuel air mixture. If the ECU sensor is reading low, the ECU will fuel the engine as if it is cool, even if it is actually running at the correct temperature. This condition is unlikely to trigger a DTC, so a scan will not show any fault.
The only way to check the coolant temperature used by the ECU, is via the OBD port, using Measuring Blocks. The coolant temperature sensor can be read in this way with any version of VCDS, even the free version. (Engine Group 001).
Failure of coolant sensors, both the temperature indicator one, and the ECU one is not uncommon.
So, a simple check may save one, two, or even three thermostat replacements, and the consequent frustration and expense. (Bad news for the thermostat manufacturers though).
Even better, a log of the coolant temperature will show it warm up, reach normal temperature, and with a bit of enthusiastic driving, or a longish steep hill, will show the temperature drop as the thermostat opens, and rise as it closes. That is, again, in my view, a very good way to diagnose a temperature related problem, .
Again, available with any version of VCDS, including the free one.
Happy logging.
Mac.
 
Munkypuzzle said:
Afternoon folks,

Apologies if this is a repeated thread but after looking through quite a few, I can't seem to find something that is as near as to bad as mine. (Also please forgive me as I am not hugely mechanically minded, but I am learning as I go).

I've just bought an A2, its mint and I love it.........but the MPG is atrocious and I need some guidance on what to try next. I am currently getting about 20-22mpg which is half of what I see others talking about and I have no clue why it's so bad. I'm averaging 200/220miles to a tank (42ltr) and I use the correct 95fuel from my local BP garage. I do only do small runs for a few miles here and there and probably average about 300/500miles a month max. I know I do get slightly better MPG on a motorway run, but I think the best I have seen is 29MPG.

It's running 17inch tyres at the right pressure, and had new oil and filter at the last service but I have no clue as to why the MPG is so bad. I thought about the spark plugs maybe needing changing, but it seems to run and pull fine so I don't think that is a real issue.

Any pointers would be welcomed as I would love to have it running as sweet and frugal as possible.

Cheers

Neil
Click to expand...
Any obvious signs of the car running rich? Sooty exhaust, rough idle etc? Have you checked the air filter is not completely blocked solid?
 
2002 1.4 petrol, for info average consumption over 7,200 miles since purchase 51.3 mpg. Best run so far, yesterday from Darlington down the M1 to Heathrow 263 miles / 17.7 litres = 67.55 mpg!
 
My last 2001 AUA averaged 45mpg over the 2 years I had it but my current 2000 AUA is only averaging 40mpg although I've only owned this since October and 90% of my journeys are less than 5 miles. It also has an EML on due to EGR fault. Both cars on pepperpots.
I'm intrigued to hear if you find out what's causing the poor fuel economy
 
Particularly if parts do get replaced, the temp sensor and lambda do benefit from being top notch genuine substitutes - on ours the lambda in particular being the proper NGK/NTK one made the single biggest overall improvement on fuel economy of all the replaced bits getting it running properly after years of mistreatment. Agree with everything else posted above.
 
Munkey puzzleI can’t add to the excellent tech advice you’re got here. I have a 1.4 and it moves maybe once or twice a week, very short 5 min journeys and idles for 5 mins or so before moving. Filled the tank yesterday and worked out last tank gave me 37.5 mpg which I’m more than happy with given how the car is currently used.
 
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