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please help up until recently i put £10 petrol in i got about 90mpg its ok... but from last week it dropped down to 50 - 60 mpg please help im only a student and its gettin expensive...
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You're sure the petrol wasn't more expensive, i.e. you got less for a tenner?
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Just before I go onto calculating this, realistically you couldn't expect to better late 40's on this car at best on day to day driving.
Are you sure you've worked these figures out correctly darrenmc? How many miles were you getting for a tenner?
It's very difficult to accurately calculate fuel consumption using monetary figures and not without filling the tank.
Best procedure:
Fill the car up and reset the trip counter.
When the petrol tank is getting towards empty - Fill the car up and note the number of litres used from the pump along with the current mileage reading.
Divide the number of litres by 4.546 for gallons.
Now divide the mileage travelled by the car and voila - you have your fuel consumption figure.
E.g. from my own Vectra recently:
358.6 miles from a filled tank
50.31 litres to fill the tank to brim again so divide by 4.546 gives 11.06 gallons.
358.6 miles divide by 11.06 gallons = 32.4 mpg
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How many miles were you getting for a tenner?
I think he means 90 miles on ten pounds, not 90 miles on a gallon..
Fill the tank up
Student, remember? Apart from the monetary implications, this could introduce all sorts of new problems, ie rusting leaking fuel tank from condensation, feeding crud through the fuel system.
90 miles on 10 pounds would be about 38-40mpg, 60 miles would only be mid to high 20's.
Has the Uno been serviced lately? Does it run rough at all? Any difficulty in starting it?
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>> How many miles were you getting for a tenner?
90 miles on 10 pounds would be about 38-40mpg, 60 miles would only be mid to high 20's.
Sorry, but at 75p a litre, you get 13.33 litres of unleaded for £10. 90 miles into 13.33 litres times 4.546 equals 30mpg ish.
I count on petrol costing me about 8 to 9p a mile for 40mpg.
Ben
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Is your Fiat Uno carb or SPI and have you also noticed a drop in performance on hills?
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Bet you've been doing shortish runs.
Freezing cold weather, choke on for twice as long as normal,price up by 2p/ltr,= lower mpg.
Mark
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Whatever the actual mpg, the point here is that is has CHANGED, quite significantly. Far and away the most common cause on this engine is failure of the distributor vacuum advance unit diaphragm. Did two in one day last week ! Only available from Fiat dealer, against VIN No., at about £15 + Vat. Fitting not difficult and does not usually involve removal of distributor, but timing needs setting afterwards.
HTH, Adam
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how can i check if its the the cacume diaphragm???
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Please don't type with your mouth full!
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To check the vacuum unit remove the vacuum supply pipe. Fit a length of suitable size rubber pipe to the vacuum unit and apply vacuum using a vacuum pump, or simply suck on the pipe. You should see the pick-up plate inside the distributor move in response to vacuum (having removed distributor cap, rotor arm, and flash guard), and if you place your tongue over the end of the tube, or clamp it with a pair of pliers, it should hold vacuum until released. If you can simply suck air through the pipe, without any movement inside the distributor, the diaphragm has failed.
The vacuum pipe removed from the distributor unit should have vacuum present at idle - if not check pipe back to port at base of carburettor.
HTH, Adam
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I would check the basics first..
I would make sure no fuels leaking out .. are the fuel supply pipes heavily corroded and leaking ?..
Then check the plugs , leads, rotor arm and distributor cap are all clean and in good condition
If the plugs are very sooty you have a fuel problem.
Make sure the choke goes off when the engine warms up and the air filter is clean (replace if in any doubt) . Check that all connections around the engine are good (remove the connectors to check their making good contact).
If your car has a carburettor the air correctors could be bunged up causing it to run too rich. Something else to check is that the advance mechanism in the distributor isnt seized if your uno doesnt have ecu controlled ignition.
If the car isnt getting hot enough (failed thermostat) replace it as your engine wont be running efficiently if its not getting hot enough.
hope this helps
steve
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