I know this question has come up a hundred billion times already...

It's just started getting hard to start too, so I'm thinking ignition module.

Up until this new developement it would start fine, but would stall if I tried to idle when it was at about 80 degrees. If I could keep it going beyond that (high revs of just keep moving) it'd go just fine. It won't always start again either. I can usually roll start it, or jump it, if I have cooperative people around. If I wait and let it cool down it will usually start again of it's own accord...this usually takes about the same amount of time as an AA call out.

If I stop for too short a time (5-10 minutes) it won't strat again until it's a lot cooler...about 60-70 degrees.

It seems to have a faulty idle unit, but I that doesn't seem to explain the symptoms.

HT leads are ok, spark plugs should be good (quite new and they didn't make a difference), does it no matter how I drive, worse when the weather is hot, but does it all year round.

I don't have much money for parts or to pay a mechanic so I don't want to be replacing parts unnecessarily. :bang:

Help?

Mia (I am sooooo getting an Uno Mia if I see one )

After a quick 'blow' I've determined that my diaphragm is in working order.

I forgot to mention that the fuel pump is new too and didn't fix the problem.

Random stalling then restaring ok, I can put down to the idle jet not switching properly, but the temperature dependant one is odd. Oh yeah, if I change the spark plugs (to cold ones) it starts again imediately.

I'd check the ignition amplifier on the side of the distributor, or the coil. Both can give similar symptoms to those that you've been having, especially when hot.

Try and substitute either for known good units and see if that makes a difference.

Yeah, see that's the thing. I can't afford to go out and buy parts to do my repairs by trial and error. I was hoping that someone would be able to give me some ideas of ways of testing what I have without the need for another car. My budget for this repai was blown a week ago, and I now have $50 (NZ) to last me until Xmas. As it is, I'm expecting car parts for presents

Oh you're in New Zealand (!)

Welcome to the forum!

Check that the heat shield is in place under the carburettor. It's a large brown 'bakelite' plate that forms part of the mounting, protecting the carburettor from the heat of the exhaust manifold directly below it (not-FIRE 1116cc engine). The heat shield tends to break off at the corners. What you're describing is possibly the carburettor overheating and the petrol inside 'burping' out and flooding the engine (hard starting and non-idling when hot). I had this on my Uno 60 many years ago You can make a heat shield out of just about anything, Burt Munro-style, so no need to spend money unnecessarily Just rivet onto the corners of what's left or use screws etc.

Incidentally when you change the plugs, you are probably rectifying the flooding situation as a by-product of letting air in to dry out the fuel.

Something else for you to try next time you're in strife - hold the accelerator pedal all the way down (do not pump the pedal!) and keep cranking until the engine starts... release accelerator only when running... the extra airflow may help to clear the flooding and get you moving again.

You mention the idle fuel cutoff sticking (or something, maybe a blocked idle jet), so if you have access to compressed air it could be a good idea to take apart the carburettor, remove all the jets (making a note of which go where), blow everything out and clean with a toothbrush and petrol (or carburettor cleaner if you're feeling like spending the $15 or so )... and now might be a good time to start dropping hints about an air compressor for Christmas; they come in useful for spray-painting, inflating tyres, running air tools... all sorts Cost about $120 from Bunnings Warehouse, SuperCheap Auto, etc.

I just thought of something else: check the wire to the throttle-stop screw (idle speed screw on the carburettor); this wire 'tells' the control unit when the throttle is closed so that it can turn the fuel cutoff-solenoid back 'on'. If in doubt about whether the solenoid is on, you can try rigging a wire from the red wires on the ignition coil directly to the solenoid (sticks out of the back of the carburettor) - this will make sure the solenoid is always 'on' with the ignition and may help to diagnose whether this is the problem.

Keeping these cars on the road doesn't necessarily cost money, it's all about having a tinker and figuring out how it works (or how it doesn't work)... Money should be spent in this order: Petrol, Tyres, Tools, Parts, Recreation, Food, Computers and Gadgets, Friends, and then garage labour if all else fails... good luck!

-Alex

Thanks Alex,

alexGS said:

remove all the jets (making a note of which go where), blow everything out and clean with a toothbrush and petrol (or carburettor cleaner if you're feeling like spending the $15 or so )... and now might be a good time to start dropping hints about an air compressor for Christmas; they come in useful for spray-painting, inflating tyres, running air tools... all sorts Cost about $120 from Bunnings Warehouse, SuperCheap Auto, etc.

Click to expand...

They're great for blowing up balloons. Indispensible if you want to fill a room with balloons to make a 'ball pool', or completely engulf someones car.

The jets are all good, they had a clean last week. I take them out one at a time to avoid mixing them up.

alexGS said:

Keeping these cars on the road doesn't necessarily cost money, it's all about having a tinker and figuring out how it works (or how it doesn't work)... Money should be spent in this order: Petrol, Tyres, Tools, Parts, Recreation, Food, Computers and Gadgets, Friends, and then garage labour if all else fails...

Click to expand...

With petrol prices these days you'd be about right, especially when my car has aquired a taste for BP Ultimate :-( Sadly, I think my computer budget is almost on a par with petrol.

I try not to spend money on workshop labour, I like being able to do things for myself where my car is concerned.

I thought of that whole vapour lock thing last night and was wondering if there was some way to prevent it. I'll check the heat shield and try rigging that wire too, it's always good to know for sure that the part being replaced is the cause of the problem....as soon as it stop raining (like that ever happens in AK).

I'm suspicious that there's an earthing problem somewhere too, as always in Unos, so i'm gonna have a good look over anything earth connections I can find, maybe clean up the main earthing strap under the battery.

I found a workshop manual online (scanned) at http://www.eserviceinfo.com/downloadsm/23944/Fiat UNO_45, 55, 60, 70.html
it covers a good range of models, free to download! Very handy. Looking over some of the circuit diagrams I find that that idle jet solenoid seems to be connected to the right indicator...weird, but that unit being faulty would explain the intermittency in that too.

If all else fails, I might resort to trying an exorcism. lol.