Hi everyone

I own a Uno Mia 2003 model 1108cc, carburetted.

I have been battling to get my fuel consumption within acceptable range for months and have spent quite a bit of money. Averaging 350km on a full tank

I have:

replaced spark plugs
change air cleaner element
replaced entire distributor with new one from FIAT
had the carburettor overhauled by a carb specialist in Paarden Eiland, by a man named Danie.

Could an expert please answer the following questions that have been plaguing me for months now, and no mechanic can give me honest, technically sound answers.

1) Is the Uno temp supposed to remain with the needle in the middle of the gauge through all driving conditions?

2) At what temperature should the fan come on.

3) What is the purpose of the breather pipe that attaches to the air filter box close to the oil breather from the carburettor and what effect does it have on fuel economy and engine operation when blocked off? According to Danie, he just blocked it off in order to drop the idle revs, saying it does nothing...

4) Does the above mentioned work with a valve, is there a valve in the air box? According to Danie it has a valve that has failed, therefore he blocked it.

The new distributor has improved my ride by miles, but I'm still having fuel issues. I can smell fuel in the exhaust fumes, but Danie said its fine and one cannot get rid of the smell competely. Is this correct or is that not wasted fuel I'm smelling?

According to Danie the C02 percentage reading should be as low as possible indicating better fuel consumption, so to him 0.60 is better than 1.35 on the emissions meter. Is this correct?

Thanks for your patience and answers in advanced guys. I really appreciate it and need help. alexGS would love your input too as you seem to know a lot about these cars.

Thanks

Hey there 5tephen

I've owned 5 Fiat Uno's, 4 in SA and 1 in the UK. None of them smell like fuel, ever, unless I've had a problem. I had a carb gasket fail on me once which leaked fuel and gave me the kind of fuel economy you're talking about.

I also reversed into a rock once not realising it had punctured my petrol tank enough to cause it took leak fuel. Obviously economy suffered.

None of my Uno's remained at the half way mark on the temp gauge. Depending on whether, SA summers even, temp would be 75/80c sometimes cooler whilst driving especially on motorway. Around town I'd get up to 90c before the fan would kick in (which answers one of your questions). 90c is the normal temp your fan should kick in.

Fuel economy wise... Many years ago I would take leisurely drives from JHB to the Vaal dam where my Dad had a yacht. I used to get 20+ km/l averaging almost 500km on a full tank. Obviously around town it wouldn't be as good. I'd get 400-450km on a tank depending on how I drove.

Post a video of your car once she's warmed up. Be sure to let us see / hear the engine as well as the speedo and temp gauge.

I'll post a clip of my 1994 Uno so you can compare.

If you're smelling fuel change / check fuel filter as well as fuel lines. Look for obvious signs of fuel leaking around the carburetor.

-typed this on my phone, apologies for any spelling mistakes etc.

If the fuel smell is only coming from the exhaust coupled with poor fuel economy then it definitely sounds like she's running too rich. What about ht leads, distributor cap and rotor? Be sure to check/replace as necessary. I had a whole new distributor once from Fiat as well but it made no difference. Turned out to be the little rotor inside instead.

Other things to check:
Timing (make sure your timing is right)
Head gasket (is she running hot all the time, losing water?)

Let us know

This is the temperature my uno sits at while driving around town.

Hi core. Thanks so much for your input. I went to the carb specialist yesterday, but he was struggling to get proper C02 readings, he took carb off twice and replaced main jets, and idle jets apparently. He says I should see how it runs now....thevcar runs fine, but I still smell fuel at exhaust. I also noticed something that is confusing me tremendously. All sources and manuals esp the Haynes Manual says timing should be set at 825 to 850rpm with vacuum hose disconnected and plugged. I do this and set the timing and all is well, but as soon as I connect the vaccuum pipe to the vacuum advance, rpm goes up to plus minus 1100rpm. Is this supposed to happen?

Hi 5tephen

I would test the diaphragm of the vacuum advance first. To test it, pull the pipe off the unit and see if you can blow air freely through the unit, if you can, the diaphragm needs to be replaced. It can be changed without taking off the distributor, i think it's just 2 screws and a plastic rod that needs prising off from inside the distributor with the cap and rotor etc. removed.

Also, don’t forget to inspect the whole length of the vacuum pipe for cracks too.

Did you come right?