Technical Uno 1.0 ie. Smelly smoke and knocking noise.

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Technical Uno 1.0 ie. Smelly smoke and knocking noise.


New member
Jan 8, 2006
I really need some help with this one. Starting about 2 days ago, when I start her up I get plumes of whitish smoke from under the bonnet. It stinks of burning plastic, a really toxic smell. After a few minutes it stops, the smell stays for a bit, then after about 5 minutes all is fine and dandy. Until she stalls for no reason lol. I also have a clicking noise coming from the front right side when I go over bumps, which seems to be getting worse. Could these be related? Need to get her fixed sharpish, don't want anything getting worse I rely on her for work!
One good thing is I found a secret ashtray in the front! The middle of the dash opens up, I never even knew it!!! Thanks for any help guys, im desperate!
Oh, one more thing, I tried taking the airbox off today, and couldn't. Undid the little nut on top but it wouldnt budge. Any ideas? :worship: Cheers.
Is the smoke coming out of your exhaust aswell?
Check your water resevoir sounds possibly like your headgasket has gone.
Take off the oil cap and look for milky/creamy deposits.
If there is do not run the car as you may cause damage to the engine.
Unos are reknowned for headgasket failure.
Not sure about the airbox on an ie as mine is carb are there any retaining clips on each side that flick down?
Cheers for the reply, nobody else seems to want to attempt it lol. There are no clips on the airbox, im guessing a bit of brute force will do. I don't think that there is any smoke from the exhaust. I will check for deposits etc, thanks for the advice. I'm inclined to think that oil is dripping from somewhere, and when it gets burnt up the smoke stops, as it only smokes for the first minute or two after startup. Would a knackered headgasket mean constant smoke? How much would I be looking at to get the head gasket replaced? Would it need any more work done on it? (assuming I don't run it) Thanks man.
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Check the cam cover gasket, as they are known to fail. If they go at the front, oil then drips onto the exhaust manifold and makes smoke and a nasty burning smell. If your water levels are fine then it could be something as simple as that!

Also check that nothing has fallen onto the exhaust manifold to cause burning.

The clicking noise could well be a worn ball joint on the lower suspension arm. Replacing it is fairly easy with a few tools and not expensive either.

As for the airbox, are you trying to take it off as a whole unit? There is a little clip at the front which clips the box onto the cam cover - makes sure you've undone it! Also make sure all the pipes are disconnected from the airbox too.

Good luck!
New development.:( Pumping out blueish smoke constantly now, also a horrible horrible screeching noise when revs are higher than idle. Might it be that my alternator is shot? Has this happened to anyone, and if so what happened? The noise stops when I push the clutch in. Im so, so desperate now, I can't afford to have a busted car lol. Any help at all would be much, much appreciated. Thanks guys.

To make it easier to "diagnose", a list of my symptoms be below:
- Rough Idling
- Blue stinking smoke, pretty much from startup now, smells really toxic
- Screeching noise like nails on a chalkboard at any rev speed above idle
- Laggy throttle (not as responsive as my MK1 uno 45s anyways)
- Stalls occasionally whilst idling
- Slight knocking noise while idling, speeds up as I increase revs but disappears when in high revs (maybe blends into one sound so I don't notice)
- Clicking noise as I go over bumps, used to be just the big ones but now its smaller ones too.

At the risk of repeating myself, I would really appreciate any help, I love my uno and can't stand to see her in the state she is. Thankyou to anyone who can help me.
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Only guessing:
Screeching sound reacting on clutch pedal pushing can be damaged clutch bearing. If so, you are facing a "gearbox-out" job. 2 people with 2 hydraulic jacks, set of wrenches and sufficient supply of the right beverages :p can handle the task over one afternoon.

However, there are two other possible sources of high-pitched noises I can think of:

a) Alternator belt (old, improperly tensioned etc.) and alternator bearing. These are more or less "cosmetic" affairs which do not require instant action as long as alternator works. The alternator bearing can be renewed (or its greasing may help), but it may be easier to get another alternator from scrappie or flea-bay.

b) More serious affair is timing belt tensioner bearing. It may be that it is worn and does not tension the timing belt properly, therefore the belt may have slipped a notch, which in turn might have caused other symptoms you mentioned. If so, its change is easy, but you need to take special care you have the marks on crankshaft and camshaft aligned properly - refer to Haynes "Book of Lies".
What are your oil and water levels?
Are you reaching normal temp if so how fast.
Get someone to rev it while u have your head in the engine bay to see if you can identify which belt is screeching.
I believe water pumps also screech when they are starting to give up
Well... It sounds like there are several problems, as I can't think of one cause for so many different symptoms. I agree with (CZ)enda's idea of the cam timing as a possible explanation. But I think you need to try and eliminate the problems one by one, and hope that the other problems go away as well.

Chas voiced my thoughts on the airbox clip. While you've got the airbox off, clean the pipe from the camshaft cover (the short black pipe ~2cm diameter) as if this breather is blocked, that may in theory cause your blue smoke issue. More on that later...

OK, the first thing I would sort out would be that screeching noise. In your first post, you referred to a burning-plastic smell. That immediately made me think 'alternator'. The alternator comes under most load directly after starting the engine. If the alternator is faulty, or there is a short in the wire from it, the load may be so high that the belt is slipping (screeching). Or, the belt may be in poor condition anyway, and may slip even under the normal high load after engine start-up.

The only thing is, this does not tally with the noise being connected to the use of the clutch. But, fixing the alternator or its belt is much easier than fixing the clutch, so I think you should eliminate the alternator as a cause first. Loosen the two 17mm-head nuts, use an extension bar and a ratchet handle from behind the brake master cylinder. Remove the belt. On the FIRE engine (which your Uno has) the belt drives only the alternator, so it's safe to start and run the engine (the battery-light will be on, because the alternator is not charging). Maybe go for a drive, listen and smell for any improvement.

Inspect the belt, particularly looking for cracks on the inside surface. If it looks glazed (it probably will) then replace it - cheap enough (5-10 pounds, maybe less).

Next we must ask: has the rough idling/stalling been an ongoing problem, or has this suddenly appeared with the smoke/noise?

If ongoing, you need to suspect the usual culprit - vacuum advance unit on distributor or its vacuum pipe, blah blah :) I'm always writing about this one! Pull the pipe off the injection throttle body (trace the pipe from the distributor), clean the end, and suck on it (yes really) - if you can draw air through it, the diaphragm probably has a split, if there is a feeling of mechanical movement and no airflow, then that's good. Having fixed this, you should probably get someone who knows about the SPi fuel injection to adjust the idle mixture/speed. Sorry, but I have experience only with the carburettor FIRE engine.

I remember with the injection model there is a switch on the throttle that must close when the engine is idling, otherwise the fuel injector puts in too much fuel and idling will be rough/stalling. So, you should check that the switch 'clicks' with the throttle closed (I think it has a black push-button) and use a multimeter (electrical tester), with the engine switched off and the two probes across the switch on the 'Ohms' range, to check that the switch really is closing.

If the problems have had a sudden onset, then perhaps it is more likely to relate to the cam timing, as (CZ)enda suggests. Remove the cambelt cover (simple - 10mm bolts, don't forget the slightly hidden one at the bottom rear edge). Turn the engine until the TDC mark lines up - I use the ones at the flywheel - there's a window on top of the gearbox bellhousing, get a torch (flashlight) and with the car in 4th gear, push forward until the notch in the flywheel lines up with the '0' marking on the bellhousing. Then look at the camshaft pulley (exposed once the cambelt cover is off) and imagine it's a clock face. At about 42 minutes to the hour, there should be a fine notch in the pulley and a wide, shallow notch in the aluminium of the cylinder head. If the pulley is 180-degrees off, turn the engine one complete turn and re-check (the camshaft turns at half engine speed).

I think you should check the cambelt tension (you should be able to twist the belt through 90 degrees on its longest run). To reduce whining noises, I tend to go for slightly less tension than this... maybe allowing the belt to turn through 120 degrees - if in doubt, get the opinion of someone who has changed several cambelts before :) Perhaps at this point, run the engine with the belt cover removed, noting any strange noises from the tensioner bearing or slackness visible in the belt.

Hopefully by now you will have found the cause of the noise... if not (and if it is still related to clutch in/out) then that leaves the clutch release bearing or gearbox noises. The input shaft bearing in the gearbox has been known to fail, but that will usually have given a roaring noise when moving off in low gears - often for many thousands of miles. I also wonder if the oil level being low/nonexistent may give rise to strange noises with the engine idling. Do the gears select normally when driving? Have you checked the oil level (12mm hex plug on front of gearbox, should be full-to-overflowing with ZC90 non-EP oil). If yes and yes, we can eliminate the gearbox. Changing the clutch release bearing is a time-consuming job, but the part is relatively cheap (you'd probably want to change the clutch as well). Perhaps leave your decision until the final chapter (below)...

...because that still leaves us with the knocks and the smoke. As PeterG says, it could easily be a blown head gasket (though I disagree that the Uno is reknown for blown head gaskets ;) I suspect it may be down to the lack of maintenance that an average Uno in the UK might get). You need to keep checking the engine oil for signs of water (cream) and the coolant for signs of oil. The coolant should be green, incidentally. Are you having to top up the oil or the coolant? The engine oil should only need topping up once every six months (say) or maybe once every three months for heavy motorway use. The coolant should stay above the 'MIN' marking for at least a month, probably two months. If you're having to top up every week - or every couple of days, or several times a journey - that is a sign that the head gasket is blown. If slightly blown, maybe one or more cylinders are filling with water after engine switch-off. But you would notice this as the engine firing on three (or two!) cylinders. Does it start smoothly on all four?

Personally I don't suspect the head gasket. I think you have either the oil leak that Chas mentioned, or (I hate to say this) maybe you have the first truly worn-out FIRE engine that I know :( The FIRE is NOT known for worn out piston rings/bores, but that would explain your knocking noise at idle (piston slap) and the blue smoke. There would also be a high oil consumption of perhaps one litre/1200 miles.

You may like to do a compression test (gizmo that pushes into spark plug hole and measures pressure with the engine cranking over, throttle open) or have a mechanic that you trust do this test for you. From memory, the pressure should be 160-170ish psi. If all cylinders are evenly less than this, the rings/bores are probably worn. You can squirt some oil in and re-test (if worn, there would be noticeable improvement) to confirm this.

If this is the case, I think you should swap the engine for one from a breakers. This much wear would be unusual (even in engines with over 150,000miles), so it is not worth spending the money to rebuild an engine that is quite commonly available. Incidentally, worn rings/bores and low compression would explain the lack of 'pep' that you mentioned.

If only one cylinder has low compression, you might have a broken piston ring, or it's still possible that the head gasket has blown. I find that if only one cylinder is low, the engine tends to make a distinctive 'stirring' sound when cranking over, as it cranks over faster for 1/4 of the time - you can hear the speed fluctuating. You would probably want to remove the head at this point for a diagnosis of the gasket.

Noises are very hard to diagnose from a description - you really need the opinion of someone in person who is familiar with these engines. I mentioned the piston slap before - by itself, not a cause for concern, but if accompanied by the high oil consumption and blue smoke, it's not a good sign. May result from drastic overheating in the engine's life. Another common (and inconsequential) noise from the FIRE is a tick-tock-tick-tock noise that disappears above idling speed. It is said to be caused by the connecting rod little-end bearings in the pistons. A change of oil may reduce the noise, but if not it doesn't matter.

Most FIAT gearboxes rattle in neutral with the engine idling, sometimes but not always because the gearbox oil level is low. Does the rattle stop when you push in the clutch? If so, and the gearbox oil level is correct, then this is also nothing to worry about.

Clicking from suspension - is this really more of a clonking? Can you feel it in the steering? If not, probably nothing to worry about. Spray the base of the suspension spring with WD-40 if it really is a clicking noise, as the end of the spring may be catching or sticking. If 'clonking', suspension bottom balljoint is the prime suspect as Chas says. I'd leave this problem for now, at least until you get the above issues sorted. Jack up the right-front wheel and try to shake it in several directions - satisfy yourself that there is nothing loose (strut bolts/steering tie-rod end/wheel bolts/wheel bearing). Usual disclaimer here: by telling you to ignore it, I can't be held responsible for damage/injury/death that results from some imminent failure! So if in doubt, get the opinion of someone experienced who can check the car in person...

Well that's an hour from me, now over to you - hope your process of elimination is successful... ;)

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Thanks a hell of alot for your replies, I will try the process of elimination and let you know. Fingers crossed that it is something like the alternator. I have a friend who used to race unos and I'm hoping that he might be willing to help me out, but anything too drastic and I'm afraid it might have to go to the garage. Its done 150,000 miles, but I want to keep her going, who knows, maybe i'll make a record! Thanks again, and I'll keep you posted.
SilentPartner said:
Its done 150,000 miles, but I want to keep her going, who knows, maybe i'll make a record!

150 000 miles = 252 000 km.

Hardly a record - my first 45 FIRE did that with only oil/filters/spark plugs/timing belt/tensioner change before the body rusted beyond repair :D . I still have the engine somewhere in a shed for the improbable case I would need it for my second 45 (which is nearing 200 000 as I type this) :cool:.
One of the members of the local forum reported 360 000 km on his 45 Fire this year...
Lol, I wasn't expecting to actually set a record. I'm surprisingly rust free at the mo.
Update on the squeaking - the update being that there isn't any anymore. Tightened the belt tonight and it did the job. No smoke either, although I haven't attempted to tackle that problem. Is there anywhere on the far side of the cam case or anywhere else that is likely to leak? (the far side as if you were looking into the bonnet, so the side nearest the back of the car) Its just I parked it on a slight decline and theres been no smoke, so my guess would be that it stopped it leaking.
The clunking noise whilst running (not the clicking as I go over bumps) is a big end, according to my dad. Does anyone know how much this would cost to get fixed? I don't want to leave it too long for risk of doing more damage.
I will check the other points mentioned tomorrow if I have time between college and work :rolleyes: But for tonight, thanks for the pointers and I'll post some more when I've had a look at the other problems.
Distributor body has an O-ring that hardens and splits. Remove distributor and check (mark distributor position carefully first). This could cause an oil leak down the back of the engine, or possibly still the cam cover gasket previously mentioned.

It would be really rare for the engine to have run a big-end bearing. Many slightly-knowledgeable people tend to reach this conclusion for any car, but these days it is seldom the case. No offence meant to your Dad, but these FIATs and other modern cars are just not given to the sort of fault that was common 20-30 years ago with Fords, BMCs, etc.

Why not keep asking around, your Dad may still be right, but it's not a fault I've ever had to fix (I think I'd just change the engine for a second-hand spare, though you can remove big-end bearings with engine/crankshaft in place. There would be a question mark over the state of other engine components (e.g. the crankshaft main bearings) though, so the rebuild could prove costly/time-consuming.)

Since I fixed the belt, there hasnt been any smoke. The smoke started before the belt slipped, and then when the belt got really bad and loud it smoked all the time. Is there any chance that fixing the belt could also have cured the smoke problem? I dont know whether the alternator could create smoke like that. The rough idling has been a problem since about a 2 months after I bought the car, and the low range torque has always been a bit poo. Is there anything I can do to increase the acceleration and improve throttle response? The knocking noise from the engine I'm not worried about at the moment, several people have said that they have always had that noise in their unos. I've had the wheel off and the clicking is definitely the CV joint, I'ma order me a new one soon and get that fixed afore the MOT, so that problem will be sorted soon. That leaves me with the rough idling/stalling and the laggy throttle.
Oh alex forgot to say I don't think that you can adjust the mixtures, as far as I know it's all done by the ECU.
- Rough Idling
- Laggy throttle (not as responsive as my MK1 uno 45s anyways)
- Stalls occasionally whilst idling
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SilentPartner said:
- Laggy throttle (not as responsive as my MK1 uno 45s anyways)

AFAIK carburettor engines are, very generally speaking, more responsive than those with electronic injection and catalytic converter.

For the other issues, I would start with new air filter.

I had the same kind of symptoms on my g/f's cinq sporting. The alternator was siezing up and causing a horrible high ptched noise, horrible smell, smoke, sparks and the power of the engine was useless. It broke down and the alternator had seized solid and the engine hardly even turned over. I cut the alternator belt off and the engine started striaght away-drove it straight home though! Try taking the alternator belt off and start the engine to see if it makes any difference.
(CZ)enda said:
AFAIK carburettor engines are, very generally speaking, more responsive than those with electronic injection and catalytic converter.

Thanks, didn't know whether it was a common thing or just mine! Went to see a fiat mechanic today, he said that the idling problems and cutting out are probably down to the distributor, so that'll be the next job on my list. Also he said that the smoke would have been an oil leak from the rocker gasket, on to the exhaust manifold, so thats another for the list. What sort of air filter would you recommend? I've heard induction kits offer more in the area of low range torque than just replacing the standard one.
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