Fiat UNO 60s - fuel/vacuum problem?

[Jeff Kay]

Guys, I need help...badly!
My 1990 mk1 UNO 60s starts and warms up a dream, until I've gone about 5
miles and (nearly always as I let my foot off the throttle) it then
dies. It will start again immediately but when I go to set off and give
it a bit of throttle it dies again. The symptom is like running out of
petrol, but if I floor the throttle it takes off like a scalded cat. All
the time its floored it goes like hell, which poses a bit of a problem
in a 30mph zone!!
I took the DMTE carb apart (several times) and checked choke operation,
float settings, lapped the needle valve checked the filter and jets, and
found nothing untoward. I replaced the fuel cut off switch on the back
of the carb but nothing seems to help.
If it goes ok flat out why not lower down?
Have I a vacuum problem? I've checked all the tubing etc., but there is
a unit on the bulkhead next to the washer bottle that I havent a clue
about.
I travel 60+ miles a day to work and while the UNO is out I'm using an
'88 Volvo 740. If I dont cure the UNO soon I'm going to have to become a
'man-whore' to pay for the petrol.
Somebody please help before I degrade myself !!!!!!

Jeff

[Peter Cross]

I had a similar problem with a mrk 1 F Reg Uno. Never really got to the
bottom of what the problem was before I got rid of the car but my garage
suspected that the inside of the fuel tank was starting to rust and was
getting into the petrol supply. A small fuel filter was fitted which
did help the problem a little but I had problems the same as you. No
power, then the car would backfire and go like the wind. The car would
also die at a stop and to overcome this I had to pull out the choke to
stop the engine cutting out!

Hope you get yours sorted. After this experience you may be put off
future Fiats. All I can say is that reliability and quality of the cars
have improved year upon year. I've had a Cinq and a mrk 2 Punto since
my two Uno's and have been very pleased with both.

Peter

[Rachael]

Hi there

The symptoms you describe are almost certainly caused by rust/dirt (from an
ageing and rusty tank as Peter said) getting sucked up into the carburettor
jets, which sadly is a common problem with older carbed Fiats. The idle and
transfer jets usually suffer first because they have the smallest apertures.
If the idle jet gets blocked, the thing won't idle. If the transfer jet gets
blocked you get a terrible flat spot about half throttle, which prompts you
to put your foot down, whereupon the car takes off like a scalded cat.

If the blockage is worse and the first stage main jet gets blocked, you get
a "binary throttle" i.e. "stop" or "go like hell." If the second stage main
jet gets blocked, you get a very good town car, because it won't go much
above idling speed.

These symptoms apply to "two stage" dual choke Weber/Solex carbs (e.g.
DMTR/DATR/CIC). If you have a smaller engined model with only one choke
(e.g. ICEV/DISA), you don't have a transfer jet or second stage to worry
about so you only get half the fun.

The jets are the brass "screw heads" between the chokes, visible from above
when you remove the air filter. Be careful with the screwdriver and have a
good pair of tweezers ready to grip them lightly and lift them out. Do one
at a time so you don't mix them up. The main jets are push fitted to the
bottom ends of emulsion tubes (they look like a miniature flute or
recorder). When you get the jet/emulsion tube out you may well see a tiny
bit of rust stuck in the jet. Blow it clean, DON'T POKE THE HOLES WITH A
WIRE! If you have good eyes you may also see rust lying in the little tunnel
at the bottom of the jet holes. This will mean removing the carb and giving
it a good swill out. Don't overtighten the jets when you screw them back.

Once you have fixed the blocked jets, by putting in a good sized inline
filter and starting a weekly jet cleaning routine, the next lesson will be
How to Drive Around Town With a Broken Clutch Cable!

Hope this helps

Rachael

"Peter Cross" <pet...@zetnet.co.uk> wrote in message
news:200202102...@zetnet.co.uk...

[Stuart Terris]

I used to have a Uno 60 also, and I had exactly the same problems.

I was told that the Solex carbs. oxidise (???) internally after 70k miles.
This blocks the jets in the same way.

I found a bottle of spray carb cleaner helped.

Hope you get it sorted soon,

Stuart

[vikramna...@gmail.com]

Thanks Rachael
After 18 years your advise had help me and my uno to become out of that problem
I had the same problem with my 2001 uno trend
First I had stucked in the road
And in hills
It runs with the initial flow of fuel
Once again thanks to all
replace the fuel filter with 40000 km