our uno '93 1.0 injection is drinking a lot of fuel. can't exactly say how much because i don't drive it but i suspect it is cca 9-11liter /100km. i noticed that temperature gauge is raising very slowly. after 10km it shows 60°C only . i noticed also that it heats the cabin OK only on max mode with fan on. i believe that all this is because of the thermostat going bad and makes it drinking much more fuel. what's your idea?

Yes, bad thermostat makes consumption higher, because ECU is injecting more fuel until engine heats up.

Uno driver said:

Yes, bad thermostat makes consumption higher, because ECU is injecting more fuel until engine heats up.

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:yeahthat:

The ecu regards the engine is 'warming up' unless the temperature goes above approx. 75 - 80 degrees. Below that the ecu richens the mixture as a form of 'choke'. A faulty thermostat will make the engine run cool and use extra fuel as a result.

Change your thermostat!

thank you both. it is 1st priority on our uno.

The 'extra fuel when warming up' - this is only on the fuel injected carbs right?

ralphnz said:

The 'extra fuel when warming up' - this is only on the fuel injected carbs right?

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also on normal engines. when engine is cold the sensor gives more fuel to run/ start better. but when the sensor is broken it thinks it is still cold when it's wormed up and runs it with bigger amount of fuel -> bigger consumption. symptoms are temperature gauge not raising, even after 15km. older cars had manual choke button near steering wheel but if you don't have choke button (usually to pull) than it is automatic.

ralphnz said:

The 'extra fuel when warming up' - this is only on the fuel injected carbs right?

Click to expand...

It really applies to ANY car - even fancy new engines use more fuel during the warming-up period. Although a heat engine is theoretically most efficient when the air is infinitely cold and the combustion infinitely hot, in practice a cold engine isn't as efficient because the fuel/air mix condenses on cold surfaces, so less of the fuel actually burns. Pistons don't fit the bores properly. Oil is thicker, so more energy is lost in pumping oil around the moving parts.

Basically, you want the engine (and oil) to be hot, and the intake air cold - except that if the air is too cold and damp, the carburettor venturi may have problems with freezing... which is one reason why fuel injection is better.

-Alex

thermostat bought. damn i read somewhere that you can also test old thermostat by boiling it in water but sooner or later it'll need to be replaced.

Replace it, it's cheap - 11 eur (original)

11eur?? i found it for 20eur. stupid, i should buy it in italy is 2km away. probably it would be +4 eur less.

so the thermostat is changed with new one. on the package it says that it is for Cinquecento and Stilo. the design, holes and the material is the same.

with old one the gauge didn't cross 70°C. now it crosses 70 but only till 75°C. if i stop at the gas station, turn it off, fill the tank and start it again, it shows 85°C/ 90°C. around 90 the fan kicks in.

tested old thermostat by boiling it and it opened itself with no problem. so is the problem solved or what??