General Crazy fuel consumption problem...

[Nick_K81]

Hi guys...

First of all nice forum. I'm the proud owner of a Fiat uno (and before the uno I had a Brava)

Its a temporary car for when I was inbetween jobs, but anyway I have nice job again and I'm using the little bugger to get to and from

The crazy thing that has happened is that the fuel consumption is through the roof. I can drive 200km's on a full tank !!
The car doesnt respond or feel any different then before, when the consumption was normal. Onley thingy that sometimes happenes when I start the car is that it seems to run on less cilinders and I can't rev the engine without letting it stall. I gently have to apply powers, and then all cilinders fire up. This is the onley thing that's odd with the car (but this has onley happened twice now)

So anybody with similar experiances ?? What could it be ? A stuck fuel valve, choke ? Its a Fiat uno 45 i.e from 1992 and has driven 95 000 km.
I've owned the car for 2 months now. Worked fine before, now I need 20 liters for 100km :S

Greetz

 

[Peterg]

Welcome to the forum.
Do a cheap check first b4 u spend any money and check the distibutor cap , leads and take out the plugs to check their condition, this may point you to one cylinder not firing.
It may be a timing issue unless it revs freely when warm at higher revs.
Of course first thing u do is look 4 a fuel leak, run from the tank all the way to the engine bay, and do not use a match as some bright sparks do!
I get about 400kms on a full tank and mines a 1108cc carb model so you as say you def have a problem with consumption.
The guys here are very friendly and helpful and I am sure will assist you in the right direction
Pete

 

[Luke]

Ive just had a quick nose in the haynes manual, and these things can also contribute to excessive fuel consumption...
* Worn jets
* Over rich mixture
* Sticking mechanism
* Dirty air filter element

Also mentions the possibility of leaks or float chamber faults.

And because its a fuel injection... Could be a airflow sensor fault or coolant temperature sensor fault.

 

[Morty Mort]

I also got 200 km on 40 litres of petrol. It was a hole in the fuel tank... Do you smell petrol when you are around the car?

Morten.

 

[alexGS]

It might depend a little on how you are using the car. E.g. if you have a leaky fuel injector, that will have a big effect for a number of short journeys, but you might not notice the effect on a long trip (have you checked the economy for a long trip?)

I think this engine has just a single fuel injector? Why not have it cleaned/tested by an injector cleaning specialist?

I lean towards suggesting this because of your starting issue you describe. Otherwise, suspect the coolant temperature sensor as Luke says. It's fairly cheap to replace, and if faulty will tell the ECU to increase the fuel at all times. Then again, so would the airflow meter if stuck... so many possibilities!

You might be best off to have a diagnostics specialist go over it, it will save you money compared with replacing parts (I think, but it depends how cheap your parts are!) Anyway, at that level of consumption you have to do something! It must be killing the catalytic convertor as well...

-Alex

 

[Nick_K81]

Thanks for advice guys.

I have ofcourse checked for puddles/leaks. My drive to work and back is onley 5 km, but threw heavy traffic and alot of traffic lights.

But the problem seems to have have gone... dunno if I'm to happy about that because I hadnt done anything yet.
The problem is probably the fuel injector, gonna have a look at it

Nick,

 

[andre79ge]

Hello!
Did you checked your vacuum advance? If it's broken, you get your spark advance really NOT advanced...
so you get flat performance! Then engine doesn't works at top of its power.

You can also check lambda sond (if lambda gives wrong signals could cause mixture to be too rich).
What about oil consumption?
A lot of oil consumption means a weak engine, and it can also cause lambda sensor to deteriorate!