Is This Poor Fuel Economy?

[Lordbenny]

23 year old 1.4 litre Citroen AX GT, twin choke carb. £25 worth of petrol got me 114 miles which equates to approximately 25 MPG. Mainly motorway miles at around 70 MPH. Shouldn't it be better than that? What can I do to improve it apart from drive less spiritedly! Im always being told that my car should be good on fuel, the diesel model was once the most fuel efficient car in the world!

[HellDiver]

Could be worse, with the snow the past few weeks I got 17.1mpg out of my last tank of petrol. I usually get 34mpg on average.

[Mark-C]

When it was last treated to a service?

[slomax]

sounds way off to me. should be getting nearer to 35 from it. My brothers 1.6 volvo S40 does 37MPG and the AX is a lot lighter and smaller, even though it is an older car, i would expect better economy than that. Not too familiar with the AX, what carbs is i on, did Citroen still use Solex ones on the AX?

Might be worth going along your fuel supply line and see if there are any leaks, especially round the tank and fuel pump. Does it feel rough to drive? It may be running rich, but i wouldn't have thought enough to alter it by ~10MPG, otherwise it wouldn't start/flood the engine.

Also if you get carb clean and spray it down the car, might clean things up a bit and might help.

[B'stard Child]

Lordbenny said:

23 year old 1.4 litre Citroen AX GT, twin choke carb. £25 worth of petrol got me 114 miles which equates to approximately 25 MPG. Mainly motorway miles at around 70 MPH. Shouldn't it be better than that? What can I do to improve it apart from drive less spiritedly! Im always being told that my car should be good on fuel, the diesel model was once the most fuel efficient car in the world!

Is it std or has it got the all essential air intake mods cone filter and noisy exhaust?

If it's std then a good service plugs and air filter - check tyre pressures (oversize tyres cost fuel)

Check the odometer over a measure distance for accuracy

Only way to accurately calculate fuel usage is brim fill to brim fill using the same pump at a filling station

- if it's a weber twin choke (35 IBSH rings a bell) watch the float needles for wear as they ridge and then let by and it runs rich as heck intermittantly

I had the 1360 Pug equivilent and aside from when I had issue with float needles it consistantly returned 37 - 43 mpg

[sn00per]

The official fuel consumption for the AX GT was 30.4mpg when new, so to be fair you arent far off. Shocking mpg really for a car which weighs not a lot and only a 1.4

[pacman1]

Carb eh? I remember a guy who had an old BX that had ste mpg. He put it down to the lack of lead in the fuel providing sufficient lubricant to the carb. The jet needle simply wore the whole bigger.

[christofmccracke]

HellDiver said:

Could be worse, with the snow the past few weeks I got 17.1mpg out of my last tank of petrol. I usually get 34mpg on average.

been getting similar

[Larry Dickman]

HellDiver said:

Could be worse, with the snow the past few weeks I got 17.1mpg out of my last tank of petrol. I usually get 34mpg on average.

I don't think that's right & would be trying to diagnose the problem.

[edo]

get it serviced.
check the air pressures in the tyres. 60 psi should help.

[B'stard Child]

edo said:

check the air pressures in the tyres. 60 psi should help.

^ needs a wink if your intention isn't to see it off the road rather than on it

[edo]

B'stard Child said:

edo said:

check the air pressures in the tyres. 60 psi should help.

^ needs a wink if your intention isn't to see it off the road rather than on it

er, seriously? I don't think so. If it needs a wink, he needs to give the license back!

[CobolMan]

I had that 1360 engine in a Pug 309 many years back; it averaged 19mpg but then the carb was knackered (at 35,000 miles) and I was too pig-headed to pay for something that should have been replaced under warranty.

[Tunku]

I do wish people who mention fuel economy would quote gallons or litres as well as price. It is fking meaningless to say "I put £10 in and got x miles"

[Jayho]

hmmmm..... is it bad that i'm running on 36PSI then? thought that was normal as its suggested by user handbook...

[sn00per]

Tunku said:

I do wish people who mention fuel economy would quote gallons or litres as well as price. It is fking meaningless to say "I put £10 in and got x miles"

When the OP has already done the math and calculated his mpg, whats the point?

[B'stard Child]

edo said:

B'stard Child said:

edo said:

check the air pressures in the tyres. 60 psi should help.

^ needs a wink if your intention isn't to see it off the road rather than on it

er, seriously? I don't think so. If it needs a wink, he needs to give the license back!

Maybe he'll get it - other readers may not - I guess was the point I was making

[B'stard Child]

sn00per said:

Tunku said:

I do wish people who mention fuel economy would quote gallons or litres as well as price. It is fking meaningless to say "I put £10 in and got x miles"

When the OP has already done the math and calculated his mpg, whats the point?

I guess the jury is still out on the accuracy of the calculation (base on information provided)

I filled the car up drove 250 miles and then put a tenner in so that's 100 mpg yes?

[007 VXR]

Lordbenny said:

23 year old 1.4 litre Citroen AX GT, twin choke carb. £25 worth of petrol got me 114 miles which equates to approximately 25 MPG. Mainly motorway miles at around 70 MPH. Shouldn't it be better than that? What can I do to improve it apart from drive less spiritedly! Im always being told that my car should be good on fuel, the diesel model was once the most fuel efficient car in the world!

my 6.0s/c V8 will do 26mpg at 70mph on the m/way

[Tunku]

sn00per said:

Tunku said:

I do wish people who mention fuel economy would quote gallons or litres as well as price. It is fking meaningless to say "I put £10 in and got x miles"

When the OP has already done the math and calculated his mpg, whats the point?

So when I search for the same problem in 2015 I want to work it out for myself?