Technical intermittant stalling, difficult starting Mia

[tracer2012]

Hi Guys
My uno has been running great up untill about a week ago. It now is difficult to start after stopping for a short while while my wife drop off the kids at school. when stepping onto the petrol it starts... Also when in slow moving traffic with your foot just slightly touching the petrol it will jerk and die -same for accelerating from standstill. This is all very intermittant and extremelt annoying!! Any ideas??

 

[tracer2012]

Please help! Uno 1100 stalling

Hi Guys just an update on my progress (i would like to think so anyway) replaced petrol pump (made no difference) replaced ignition module (made some difference)
car still has flatspot when you just touch petrol, especially after turning, or going oer hump in road sometimes so bad it just stalls and then you struggle to get it going again. The only way to get it going is by flooring the petrol and gently ease of it untill it awakes. I also u sed lots of carb cleaner and emptied bottle of fuel system cleaner in tank as well. Made some difference - the thing is the problem seem to only get worse as you have been driving for at least 30 minutes of stop and start not just 10km at a time. I did see some pipe was not connected at the back of the carb it goes to a vacuum type device on the carb itself. conneting it made no diiference to the problem though. Any ideas should I check the float level?? Please anyone??

 

[tracer2012]

well while im monologuing let me carry on! maybe some of this might help someone..

None of the above that I have done so far has helped. What I did try this morning was to gently pulled out the choke a tiny bit to up the idle speed a bit, and smooth as butter. This didn't help for it not starting when hot though............

 

[johorridoh]

Looks like you have a SPI Version.
The butterfly valve potentiometer wears over the years.
Try to get a working Injector unit and replace it.
Jumping ohm signals confuse the motor management unit.
That why these odd symptoms occur.

 

[tracer2012]

hi Johoriddoh - thanks -
car got so much worse yesterday it completely died on me cut out on high revs as well with loads of black smoke from exhaust. Car even struggled to start when cold it was so bad it left me stranded after work. I had to have it towed back to my home last night. But I,m happy to say that tonight after taking of the carb off i found one of floats inside the carb was indeed filled with petrol. I managed to empty it after drilling a tiny hole filled again with water and made 100% sure it was empty then melted it close with soldering iron. What is a bit disturbing is that I could not find the hole causing the leak in the first place...... took it for a run started normally with choke when cold and on first turn when on normal running temp. I took it for a run, its 95% better the only thing bothering me now is a slight miss at high revs I read that adjusting the air fuel will not affect the mixture at high revs is this right? maybe /i nedd to check the timing. I did clean the carb while i was at it. and also undid the air fuel mixture screw but took note of the amount of turns and turned it back in the way it was.

 

[tracer2012]

oh yes i also checked the valve timing it that was still fine

 

[johorridoh]

As I see you really have an carburettor version.
Well that´s ages ago that I had one.
Notice that some rubber parts and sealings may
get hard over the hears. You may remove the
carburettor and clean the whole thing in a
special carburettor fluid bath. Then check all
hoses and sealings. The butterfly valve can wear and
then you must get a whole new , or better unit.

 

[bedofercni]

Miss at higher revs means that the air fuel mixture is too weak. Too much air in the mixture means somwhere at the seals ,the carburettor are leaking and sucks false air. If you didnt change te gaskets in the carburettor you should do that. Weak mixture can damage your cylinder head.

 

[tracer2012]

Hi Thanks for that info - yes indeed, I was extremely hesitant to change anything regarding the carb setting and float level since the previous owner had it set at his dealer and shown me the receipts just before he sold. But I'm happy to report that I did indeed changed the fuel/air mixture until it ran smoothly on idle and it made a HUGE difference not only when idling but also on high revs. The engine is running smoothly now!! It would be interesting to see how that air/fuel mixture setting I did affected the petrol consumption

 

[tracer2012]

just to report back that the fuel consumption has never been better! But sadly also that the float filled again even after finding the extremely small hole and melting it close again. It left my wife stranded without prior warning - bummer! So I eventualy sourced it (only from agents) and fitted it last night. So far no more issues beside that slight hesitation when under load, like going uphill. only when you step on the petrol a bit more will it go - if you know what I mean.... Could this be vacuum advance? I did check it and it works by sucking on the pipe... I also noticed the hot / cold air flap seem to be stuck in one position only taking in hot air...any ideas if this might cause the hesitation?

 

[alexGS]

Good to hear you're making progress with this.

The hot/cold flap is a common age-related failure. Unless the temperature gets down near zero in damp conditions (carburettor icing likely), I think you're better to jam the plate in the cold-air position. Probably won't affect the hesitation though. Have you tried a new set of plugs and a check of the ignition timing with a timing light?

-Alex