General Fuel tank filler vent blocked and cut outs

[Mazz0]

I have a Uno 45 with Fire Engine Carb (not injection)

I have been reading this forum for a while find and identify my problem. Some time out of nowhere the engine cuts out and won't start again until a few minutes have passed. Then when it finally starts it sounds very wierd (sometimes dies again) and hopefully sometimes it goes back to normal and I can drive for 2-3 days until this happens again.

One day I was reading the Hays manual when I noticed under fault finding that said this might be caused to Fuel tank filler vent being blocked. This is true for my car. I have noticed that when I go to fill it up in the petrol station, most of the times whenever I open the cap it sucks in air like a big 'ooooff'
This led me to believe that my tank filler vent is blocked. I don;t know if my problem may be due to this cause but just in case, I wasnted to ask you,

Where exactly is the fuel tank filler vent ? I know it should be near the cap but how will I reach it or find out if its blocked and/or how to clean it ? Anyone came across something like this ?

 

[Morty Mort]

The "ooooff" is supposed to be there. There is an underpressure in the tank. Anyway, air is supposed to get into the tank (and replace fuel, else it would implode. But the fuel pump is not powerful enough to pump fuel out of the tank if the underpressure is to high. So when when the car stalls on you the next time, rush out and remove the cap, and try starting again. If it starts it may be your cap that needs a replacement.

Morten.


abarth alloys, steering wheel. inter alloy lowering. phoenix gold audio. refurnish.

projects: induction. seats. exhaust. tinting.

 

[Neojames2k]

Do you always fill up at the same place?? I found I had a similar problem when i filled up with supermarket petol once, my uno didn't like that at all. Morten is correct the "ooooof" noise is the difference in pressure between your fuel tank and the surroundings.

NeoJames2k

 

[Mazz0]

my cut outs are becoming so heavy now.
It will run fine for 2-3 days but will cut out every 10 minutes on a day he doesn;t like. Trying to find what's wrong. by the way I noticed 2 things.

I was wrong (Correction) When I open the tap, air goes out, not in. It blows a breeze of air in your hand.

This happens every time I open the cap. not just when I got to fill it up. Like I drive for two miles and if I open the cap it blows out air. You're like driving and suddenly the engine stops like you turned it off. This isn;t very similar to the other FIre engines dieing when idling. mine just stops while on acceleration. just out of nowhere, no reason.

I have changed plugs, all plug leads, new air filter, distributor cap and the rotating thingy inside.

what I did today is cleaned the cap really well. it had all sorts of limescale on it. I cleaned it up good with viacal, now it turns around smoothly, I hope the air vent on it will be free now. (I drove a couple of miles, opened the cap and it didnt blow air)

What I'll do next is clean the carb with them specific sprays in case its my carb.

fingers crossed :/

 

[Mazz0]

By the way I noticed the fuel filter sometimes beeing almost empty, sometimes being all the way full. anything to do with it ? or is that normal ?

 

[lashlondon]

..the fuel filter could be a red herring...mine runs on empty too...

..the Fiat fart:I at the petrol cap is normal...run the car without a cap, it still fails, u know it wasn't that..(stuff an old sock in there..)..

...most importantly..grab an old spark plug...next time it fails..wip off a lead, turn it over...no spark mean electronics may have failed...

...does it fail only when its hot? Electronics again...

chase up the panda guy...forgotten his name...search out his advice on this when I had what sounds like the same problem..

replaced my distributer..never had a problem since..(£60)

Dave

 

[Peetie]

If this happens when hot it is probably the distributer. The cause is the insulation breaking down between the hall sensor inside the body and the amplifier module outside. This fault is common and will occur on higher milage cars ie 50,000 plus. the car will usually restart after the engine has cooled a little.
You could also check that the idle compensator(thats the gold round thing on the side of the distributer) is working, suck the tube that connects it to the manifold, if there is resistance it is ok if you suck air you need a new one, about £20 from fiat.
Failed compensators will cause a rough idle and possibly stalling but will allow the engine to restart right away with a litle throttle....
Hope this helps.

 

[Mazz0]

Ok guys ! it seems my problem is solved and most importantly I'm proud because I fixed it myself !

I think this is the very common problem all FIRE engines have when getting HOT. It the electronics of course and on mine it was the distributer. Here's how I traced down and fixed my car. I hope this will help other people here.


At the beginning I thought it was the fuel cap. well that proved to be normal as many of you said earlier. I run the car with no cap and still had the problem of stalling and all so it wasn't that cap. that air pressure difference seems to be normal in cars like this.

I moved on to check the ignition coil. I read in the Haynes manual the proper Ohm values the coils should have and I checked mine with a multimeter. They seemed almost fine a bit off of the manufacturer's values so I bought a new ignition coil just in case. After running the car around to get it hot I still had the problem so it wasn't the coil.

I bought a carb cleaner spray which did an excellent work on the very dirty and oily carb and made it shine as new. Still the problem was there although I got a really good response after the carb cleaning and I was very happy.

I cleaned with a WD40 (untirust oil spray) all the earth (ground) points which appeared to be heavily rusty. You can find the earth point just below the battery, behind the left head light of the car.

Still had the problem so I took the distributer to pieces.
on my distributer, there is a circuit board which has a big heat sink. This circuit board mounts on the back of the distributer and has 5 connections. One is earth which mounts below the circuit board on the distributer with a screw. 2 other cables run with a plug to the ignition coil. 2 more go inside the distributer on a magnet which is controlled (up and down) by the vacum advance unit.
this circuit board joins with them 5 cables with a connector which was reaaaaaaaally rusty. all my connections were green and I figured the couldn't be cleaned and was the reason for making my car fail when hot. What I did was replaced this circuit board and the vacum advance unit which was also in very bad condition. Put everything back together in the distributer. Car now has a really smooth idle starts and runs better like a clock.

I didn't have the strobe unit to adjust the right angle of the distributer so I did it manually. A good friend told me to find the best angle by trial and error. you can listen when the car has a good idle running and when not. He also told me to go behind at the exhaust and put my hand. If there were "knots" of air popping at idle then I had to change the angle. So I did, I configured the angle such a s the car now has a perfect idle running and the exhaust spits air normally. I also noticed a lower consumption of fuel and I'm happy that my car is now healthy and running perfectly.

Hope this will help others that have similar problem.

Vacum advance and the elctronic circuit board for my Marelli distributor costed me £35 pounds or 50 euros. I couldn't find any in UK so I ordered them from a friend of mine who has his cousin in a FIAT spares store in Greece. hehe

Brand new distributor they said costed £120 pounds and wasn't really new. repaired unit and I had to turn over my old one to them.
Anyways hope this helps, Fix yer Uno !

 

[Martiny10]

I had the very same problem and reached the same solution with my Lancia Y10 Fire - same engine.

Rather that buy a new module the average scrapyard should contain a few examples, but it may involve checking different brands of car.

The 999cc FIRE engine is used in some 999CC Panda's, Y10's, SEAT Marbellas and 999CC Uno's and the distributors are interchangeable. The small electronic module may appear on other cars too, for example 1.3 Lancia Delta's have similar looking electronic module but a different style of distributor - I would put money on it working. I replaced my Y10 module with one from a Panda.

Cost £5.

Regards,

Martin

Fix It Again Tony!

 

[Sri Lanka Fiat]

Hi,

I have fiat uno IE 1995 car, but it was converted to Curb ( Y10). I have same problem, the car is miss fireing. It is runing soo good 01 day but missfiring coming againg. Please help me.