General is it the fuel pump or a blocked tank vent..

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General is it the fuel pump or a blocked tank vent..

lashlondon

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Hi all

Its a Fiat Uno Fire which simply stops in heavy traffic or under load...the fuel filter bottle is always empty when this happens..

..if its the pump, no probs- that seems easy to whip off, but if its the breather hose on the tank (as there is always suction on the petrol cap when it comes off), where in the world is this! I had a look the other day, got the fuel outlet pipes but couldn't see the tank breather hose...

whadya reckon?

Dave :)
 
Hei.

I had to change my fueltank last winter. I had struck somtehing sometime earlier, which started a corrotion under the tank. Suddenly there was always this (lovely) gasoline smell around the Uno, and it started to use over 1 litre of gas on 10 km. In Norway we don't have gallons or miles, but 1 litre per 10 km is very much on this little engine (1.1i.e). It usaually consumes 0,65 litres per 10 km in city driving though.

Anyway. The tank has one large fuel hose. Beside this hose there is a smaller one, maybe 1" thick. It goes up to the petrol cap area. The petrol cap should make a suction noise when opening. Two hoses are attached to the pump. So - actually there are no breather hose. I did som studing when I changed it myself, because I couldn't find the vent hose. The ventilation is contained within the system. Vapour is driven through a carbon filter and returned to the engine intake.

But I have no idea what might be wrong.

Morten.

I had to do some editing here:
Just for information. The Uno I own is a 1993-model with metal fuel tank. I know some Unos have plastic tanks. These I have no experience with.
 
Next time it stops, open the bonnet and get someone to watch the fuel filter bottle when the filler cap is removed - see if it suddenly fills.

The other thing which is usually ignored is the fuel filter - might be worth a look at.

Regarding fuel tank pressure, or vacuum - I can't clearly remember - but ISTR that injected systems are pressurised by the return (over supply) of fuel from the injector, and carburetted have a slight vacuum, which can cause the tank to collapse if there is no "leak".

FWIW I understand UNOs will sometimes make a spontaneous "fart" :I noise when parked up as pressures equalise [:0]
 
Thanks all, I can't figure out the whole breather pipe thing, I can't seem to find it under the car or around the petrol tank,....maybe as you say that - these plastic tanks don't have a breather at all but its all internal but that doesn't seem to make sense...

...can't there seems to be quite a bit of pressure in the tank as when I disconnected the fuel 'out' pipe the petrol poured out of the outlet even though it was on top of the tank...so there isn't actuall suction in the tank but a positive pressure....is this from the petrol fumes or is this air being pumped in from the fuel pump...

Had 3 RAC call outs on this on Saturday...they dunno either...the last guy reckons it could be the carb sticking or something but I've never worked on carbs so I'm hesistant to go there (he also in the same breath had a look down the carb and said the injectors were fine..)

...lost on this one...[?]

lashie
 
Hi m8,

I had exactly the same problem with my Fiat Uno Fire, it went on for months and months. I called out the RAC so much they stopped picking me up!!! Anyway, I replaced the metal fuel tank, the pipes, tried different carburettors, and this is why I didn't expect to get stuck so many times. However I did start to get somewhere when I replaced the 'furred up' ignition pack situated on the distributor... it controls engine speed ignition timing, the works!! Having replaced this, it didn't stop anymore... so I decide dto get the car tuned AGAIN and I noticed the vacuum was replaced on the distributor. I haven't looked back, I nearly had given up but you will get there!!! I tried everything related to fuel contamination as this is what the RAC thought was the problem, but it sounds very similar and I think try the distributor and ignition pack first, its cheaper!!

Tell me how it goes

Cheers
Nick
 
Sounds like a winner [^]

I'll run the little monster up a few hill tonite (having disconnected the fuel lines last night to make sure they're running ..which are with gusto ), if it stops again- then electrics we shall go..

thanks for the tip:D

will let u know whats the verdict

Dave
 
Hey, Mr Fiatunofire

Ran the Fiat up the M11 last night, NO PROBLEMS.

I reckon ur right, it must the ECU -ignition pack thing (that is what ur meaning right?)...

..is it a case of just replacing it or do I need to retune the car after that...

my current theory is that...

..the motor gets very hot, the ECU ignition wots-it shorts (or something like that), the car dies---which is why the Fiat only died when it was hot....

whaddy reckon [8)]

Dave

PS Still doesn't explain why there's considerable positive pressure in the tank or where the petrol tank breather pipe is...Fiat dealer reckoned that the breather was up near petrol cap ([:eek:)]) ....I reckon its not...
 
The ignition unit is a is a stock fault, but...
your initial set of symptoms

<blockquote id="quote"> face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by lashlondon


...the fuel filter bottle is always empty when this happens..

<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

doesn't really point to that being the problem.


whadya reckon?
 
..true ..

..but I shot up the M11 to Stanstead and back last night and the filter bottle was almost empty at the start...and almost empty at the end..but the car was fine !!??

...I have no idea how petrol gets into the motor...

somedays the filter bottle is half full at start up, but generally it empties...


Taking the Fiat to wales this weekend.....

lashie:D[?]
 
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