Poor fuel economy

MrMatteh

MrMatteh

MrMatteh

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Joined
22 Feb 2004
Posts
2,417
Location
Essex
I came back from uni today ~ 220 miles. i sat at about 75-80mph max. most of the way (few sections of roadworks).

however, this took an entire tank of petrol! the light came on just as i got home! normally it takes just over half.

Before i left, i topped up the coolant but i think i might've filled it up too much. the temp guage was at ~ 0 the whole journey (temp guage normally works). Am i right in thinking that this would cause the engine to be running with the choke on, thinking it was cold, shattering my economy?

car is a mk1 1.8 8v clio
 
No idea what the problem is I apologise, but I see an oppertunity for me to whine....

My 1.3 (naff) Fiesta get 270 miles on a whole tank, thats £35 from 59bhp. Nobody EVER buy a 1.3 Fiesta ffs. This includes maybe half the tank or more of motorway work.
 
MrMatteh said:
I came back from uni today ~ 220 miles. i sat at about 75-80mph max. most of the way (few sections of roadworks).

however, this took an entire tank of petrol! the light came on just as i got home! normally it takes just over half.

Before i left, i topped up the coolant but i think i might've filled it up too much. the temp guage was at ~ 0 the whole journey (temp guage normally works). Am i right in thinking that this would cause the engine to be running with the choke on, thinking it was cold, shattering my economy?

car is a mk1 1.8 8v clio
Click to expand...
Something is wrong even my MR2 Turbo can get 300miles to a tank on a motorway run but that does have a fairly big 55L tank.
 
how wierd. have you checked there aren't any petrol leaks? my astra had a minor leak but repairing that made the difference between 350 and 450 miles per 50l tank
 
this is a 40L tank.

normally this journey only takes ~ 1/2 a tank, i usually get about 350-380 miles/tank.

just wondering if the thermostat being 'stuck' on a cold setting would cause the car to run richer.
 
well it depends how the ecu reads the temp.

the thermostat being stuck open would make the car take longer to heat up, by maybe 5-10mins longer.
the temp sensor could be faulty (~£3-5 from a motor factors) or the connector to it could be corroded and needs cleaning.
its also likely that the ecu reads the temp from a different sensor.

so i would be looking for a petrol leak, from the fuel pipes, filter or tank especially as the car is a mk1 and is at the age when things like hoses and fuel pipes are old and brittle.
 
you think that is bad i got 240 miles to a full tank of motoway milage in my old Renualt 5 1.1 47bhp engine now thats pathetic worked out about 27 MPG, now i own a 1.5 engined car and can easily get 45 MPG.

thedazman
 
Managed a trip up to Essex from Devon and a few trips while we're here and I've got just under a quarter of a tank left, 10 gal tank iirc and the trip comp reckons an average of 37.5mpg. And that's for a mk1 172! I know an 8v is generally seen as less efficient than a 16v, but I'd have thought you'd get more than that out of it.

Problem I've found with less powerful cars is I tend to be heavier with the go pedal. Unless I'm pushing it I rarely need to press hard at all on the accelerator to make decent progress, not the same can be said when driving the 1 litre micra :)
 
I usually get about 320 miles to a tank in a 1.8 VTI Civic, the most I've had is nearer 340 odd but until I got my wheel bearing sorted I was getting 280. Thats a 55l tank as well!
 
Sounds like your CTS has packed up or your thermostat has seized open.

If your CTS is broken the car will always think its cold and overfuel itself. If the stat is open constantly the car does not get a chance to warm up as all the coolant is directed to the raditor straight away.

the thermostat being stuck open would make the car take longer to heat up, by maybe 5-10mins longer.
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Incorrect the car will not warm up at all unless you leave it their idleing. If you are on a motorway the car wont warm up at all (coolant wont but the oil will just)

1.8 8v? is that the RT or RSI?
 
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Acolyte said:
Sounds like your CTS has packed up or your thermostat has seized open.

If your CTS is broken the car will always think its cold and overfuel itself. If the stat is open constantly the car does not get a chance to warm up as all the coolant is directed to the raditor straight away.



Incorrect the car will not warm up at all unless you leave it their idleing. If you are on a motorway the car wont warm up at all (coolant wont but the oil will just)

1.8 8v? is that the RT or RSI?
Click to expand...

its the RT (no one would quote me for an RSI, didnt even bother with the 16v ;))

*normally* its fine, im going to drain the coolant a bit later and go for a drive (need to go to enfield) and see what happens :)
 
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