Technical Uno Mia Misfire

Currently reading:
Technical Uno Mia Misfire

Tracer

New member
Joined
Sep 29, 2010
Messages
4
Points
2
Location
Stellenbosch
Hi All
New to the forum and allready finding it very usefull. I bought a 2002 Uno Mia 1100, 2 weeks ago. The car runs fine apart from a slight misfire/unwillingness to accelerate. My wife don't seem to complain but I find it quite irritating. It is obviously not as fuel efficient as it's supposed to be. There is also a 'noise coming from the distributor when the engine is at normal operating temp. It was a one owner car and has full service history. I also assumed the timing belt has in fact been replaced at 75k...
My question is this - is there a sure way for me to tell if it could be the timing belt that is stretched and maybe causing the noise at the distributor side. I would hate to just start on a spending spree not knowing what exactly is causing this misfire problem. Any other ideas what may cause this? Also does anyone have experience with his her timing belt broke on a 1100 fire engine and did it damage the engine?
Any help would be appreciated!
 
The noise from the distributor is unlikely to be anything to do with the timing/cambelt, in my opinion.

If it is a ticking noise, it may be arcing between the terminals for the leads - I have seen this, especially at night when you can see the blue flashes. Obviously, you have to avoid touching the distributor cap when the engine is running, if you have this condition!

If it is a grating plastic noise, pop the cap off and check the dust shield is correctly in place below the rotor arm. Also, check the metal contact in the rotor arm hasn't come adrift. And finally, check the spring-loaded carbon button in the distributor cap, which should be at least 4mm long. If any of these things are dubious, replace them with new items (the dust shield is not essential and can be left out if a replacement is not available).

Arcing between the leads will certainly affect engine performance, worse at certain engine loads.

Also, throw in a new set of spark plugs and check the leads, though being a 2002 the leads should still be in good condition (I've seen twenty-year-old leads still in perfect condition).

-Alex
 
Last edited:
Hi Alex thanks for this info - I will check out the distributor to see where that noise is coming from. I have replaced the thermostat as you've suggested in another thread and WHAT A DIFFERENCE!
I take my son to school in the morning and we live just outside town about a 9 km return trip. The car usualy only started to run better on my way coming back home. This morning I let it run a bit to check for leaks but not long - about 3 min - and it was responsive as soon as I took it out of the gate! I haven't checked to listen if it was still misfiring though but the engine was willing now. The choke cable was also to tight resulting in it idling a bit high so I've adjusted that too. Now just for that noise in the distributor and then to replace the rear wheelbearings. Does anyone know how complicated it is to replace the rear wheelbearings?
 
Hi, great to hear you're making progress. A little TLC goes a long way in making these cars nicer to drive. You've found the choke cable - another I find pays dividends is the clutch cable - take the 'eye' off the pedal and grease it (if the clutch is at all creaky!) It can be adjusted at the other end - tighten the nut to raise the pedal. Way off topic but I've noticed what a difference this TLC can make :)

Rear wheel bearings are relatively easy (compared to the fronts) as the hub comes as a complete replacement with the bearings pressed into place. This job gives you an excuse to service the rear brakes (perhaps take a drum off before you start and see if it's worth getting new brake shoes before you start on the job. Shoes should have at least 3mm of friction lining, in my experience, for the handbrake to work well. Another culprit for the handbrake is the curved metal levers that have the cables attached - this is a good time to replace or at least re-grease those).

The actual hub replacement just involves prying out the bearing cap and undoing the nut on the stub axle, then ideally using a puller (or a pair of crowbars) to get the hub off (this is when it may be necessary to remove the brake shoes, for access). The new hub should come with a new nut - do it up to the correct tightness, no tighter or looser (I don't have my Haynes manual handy) and replace the split pin (if applicable). Re-fit the brakes.

I'll post back when I have that torque figure to hand.

Wheel bearings are usually long-lived (I can't remember when I last changed one) but perhaps the parts used on your car were substandard or not greased properly. If one has failed at a relatively young age, I guess the other isn't far behind, hence your use of the plural, 'bearings' ;)

-Alex
 
Last edited:
Hi Alex thanks once again for sharing this info and your experience!
I had a quick look yesterday inside the distributor cap and yes from what you told me you were correct! There was a plastic cover in there that was loose - which I have now removed. This has made a difference to the noise coming from the distributor allthough I still hear what seems to be 'grinding' noise. (I remember you mentioned to check the metal contact in the rotor arm which I will still do, also the spring loaded carbon button is still exceeding 4mm) The noise is not as loud as before but still noticable. BTW I enquired about a new distributor and it is almost 2/3 of another engine (R3000) Which is probably what a garage will tell me should I take it in to resolve the 'noise issue! No way to that thank you very much!
I also noticed this morning after filling up again that allthough the pump attendant tried his best to fill it to the brim (and he did) when I started it it still wasn't full, the metre showed it could still take some more fuel and working out the consumption proofed it as well. Could this be caused by faulty breather pipes?
Regards Jacques
 
I also noticed this morning after filling up again that allthough the pump attendant tried his best to fill it to the brim (and he did) when I started it it still wasn't full, the metre showed it could still take some more fuel and working out the consumption proofed it as well. Could this be caused by faulty breather pipes?

I guess it could be a kinked breather pipe - inspect it from the filler neck down to the top of the pipe into the tank?

I've had that filling problem with lots of different cars - my Mk2 Punto was especially bad - I think my Uno is easy to fill but then again, the Turbo has a different filler neck arrangement (includes an auxiliary tank at the base of the filler for another few litres and this probably smooths the flow into the main tank).

So I think this is a problem to ignore for now - try a different filling station - I had a huge job getting petrol into my Alfa 156 the other day - had to go really slow - and have never had problems before, so I really think it varies between pumps. Try also rotating the nozzle until the handle is practically upside down. Of course, in NZ (and England) we operate the petrol pumps ourselves, the concept of 'service' having been lost from 'service station' :p

-Alex
 
Last edited:
Hi Tracer,
I also own an 1100 Uno Mia, I've had the car for about six years now and still love her! I read in your post about the cost of a new distributor, yes they are very expensive but just let me say don't be tempted to buy a 'pirate' one from somewhere like Midas. I was tempted at the R500 price of a new distributor from them and lived to reget it! The first unit lasted one week and failed on the N1 at 7pm one cold winters night! The second replacement unit lasted two days and it too failed while in heavy traffic - not fun! In the end I bought proper Fiat parts for my old distributor from the agents and although they weren't cheap they have lasted three years so far with no further problems.
Good luck with your Uno!
Andy
 
Back
Top