Technical Problems with my 999cc FIRE engine

[Luke]

Your trusty help is needed for my poorly 999cc FIRE mk2...

Problem 1:
I have an idle problem when cold. Basically one minute its fine, then it sounds like its firing funny and the exhaust blows out with alot more force. the revs drop and bounce between 500 and 1k, and you can smell more petrol.

Different amounts of choke dont seem to be solving the problem. I had originally put it down to the cold but it was a nice warm day today and it still did it. As soon as its warmed up or the engines got into its stride, its fine. So could it be possibly something to do with my carb - like deposits in the idle jets or dirty throttle body?

If so, do any of you know where i can get hold of a reconditioning kit (gasket, vacuum unit for the carb, and whatever else i needed to do a proper service)?

Problem 2:
Could my Cam be knackered? My engine had run for some considerable time with no oil pressure and subsequently has worn/burnt my cam. The valves didnt look too healthy either. So when im driving around when its colder, the car badly lurches forward and looses ALL power momentarily - its as if you go and it stalls (without engine stopping). As soon as it warms up (50 deg.) its fine. Its also fine cold with at least 2k of revs on the choke. Any less then it does it.

Problem 3:
The breather tube on the engine that goes into the airbox... Is that supposed to be sucking in air via that way or blowing air out?

Basically it seems like mine is using it as a secondary exhaust as it constantly blows exhaust gases through it into the airbox, and in turn, straight down to the carb again.

Problem 4: (Last one)
I have a slightly wierd idle now i've put back on a new vacuum advance unit. Sometimes in town driving the idle is fine, about 900 revs. But when on the motorway and driving around a little faster, the idle usually sits at 1200 but fluctuates a 100 or so. Whats causing this??



So as you can tell, im either paranoid about my poor engine or its truely poorly.

 

[Louie Bee]

Hi Luke,

That’s a few concerns. When did you lass service and tune your beloved?

Problem 1:
Do you know how old the rotor arm and distributor cap are? How about the points and condenser if your distributor has them (I’m not too sure on 999 wiout IE). Also condition of spark plugs and HT leads? The non-IE fire engine uses different plugs if I remember rightly.

Problem 2: - Pass
Problem 3: - TBH I think it should suck Morty Mort warned us about fitting a breather filter when fitting Induction to stop the breather Sucking in dirt and messing up the cam top.
Problem 4: - When you did the Vacuum advance, did you check its rubber tube for leaks? How about the timing as this may have been set with a knackered advance.

Regards All,

 

[Morty Mort]

Hei.

Problem 1. Pass

Problem 2. The cam has a has a very thin layer of toughening / hardening / tempering (please pick correct word). If your engine overheats this layer will get damaged and then worn out. When this occurs the cam will be totally eaten up, to a complete circular shape - just as the cam shaft itself. This happened on our Ritmo Abarth when a coolant hose exploded and led to a hot (not overheated) engine. But that was all that it took to destroy the cam. Particlurat the exhaust cams were damaged, blocking exhaust gases from coming out. This again led to exhaust find anouther way out - through the massive air intakes in the front, and led to a braking effect on the engine, jumping car and small explotions under the hood. It is a possibility the cam has got to hot without the oil pressure. Check this. It is easy to spot a knackered cam. Just remove the rocker cover.

Problem 3. The breather is supposed to breathe out the extra pressure in the engine. This is why it acts like an exhaust. But it will also create sucktion, hence the importance of a breather filter. Yours is propably in good order.

Problem 4. Pass.

Edit...: Some pretty bad English in this one. Hehe.

Morten.

 

[Luke]

"That’s a few concerns. When did you lass service and tune your beloved?"
- I generally service it every few thousand miles to check all is well, but did a massive overhaul when i first was given the car. Took the head off and cleaned all that i could, sump off and cleaned the crank etc, waterpump and oilpump got a clean. Basically all was cleaned or replaced. The only thing i couldnt was the cam which was burnt at one end.

"Problem 1:
Do you know how old the rotor arm and distributor cap are? How about the points and condenser if your distributor has them (I’m not too sure on 999 wiout IE). Also condition of spark plugs and HT leads? The non-IE fire engine uses different plugs if I remember rightly."

It had a new rotor arm and dizzy cap not too long ago IIRC, took a look and theres a tiny bit of pitting on the end of the arm - but nothing to write home about. Not sure about condenser, but dizzy seemed to be in good condition when i changed my vaccum advance.

"Problem 4: - When you did the Vacuum advance, did you check its rubber tube for leaks? How about the timing as this may have been set with a knackered advance."

The tube was checked and its fine, as was the timing. My timing was set with the vaccum advance plugged (non operational - as you should) for ages as my old unit was knackered. In theory the timing shouldnt have changed although i did double check and no difference.

Thanks anyway Louie and morten, much appreciated Its probably me just being over paranoid again

 

[Louie Bee]

Merilli Distributor Condenser

Hi All,

... Not sure about condenser

If you have Points then you may well have a condenser (Capacitor). I remember form my 903 OHV the points were a right B**er! till I moded the distributor the gap would always slip.

As for a bad condenser, I found the car would intermittently kangaroo down the road, and then be OK. I'd tried everything else first...

All OHC have Merilli distributor while the OHV have Ducellier type (if not digiplex or Multiplex according to Porter manual).

Back to the OHC 999 FIRE, from what I can make out only the Injection models have brakerless ignition (No mecanical points) – could be wrong. There should be a points’ gap inspection window on the Merilli. I presume there will be a condenser somewhere? I couldn't tell you if the symptoms would be the same if it were faulty.

Speaking of Distributors, I'm just working on the brakerless one I pulled from Spam0r's Uno . I’ve just replaced the O Ring gasket which AlexGS tells us kills the clutch if not fixed – (middle right on attached). I think Ill post my questions on that thread soon (to keep on the topic…)

Regards All,

 

[whatoncewas]

You took the sump off and cleaned the crank? Is this easy to do then??

I cleaned the 'top' when changing the rocker cover gasket. The rocker cover itself had loads of gunk stuck everywhere on the inside. Couldn't actually properly clean anything below the camshaft though - there was oil there (I assume that's normal?).

Got a photo of what it looks like when the sump is off?

 

[Chas Uno]

Regarding Lukes problems,

Louie, if I recall correctly, all the FIRE engine equipped Uno's had electronic ignition. Both my '86 1.0 FIRE Uno's were so equipped. I think the OHV models had contact breakers up until the mk2 shape, and also the pre - '86 OHC non FIRE models had contact breakers.

The Pandas with the FIRE engine had contact breakers, except for the 4x4 models which had electronic ignition the same as the Uno's. This is the same as I got one from a scrapped Panda and fitted it to my older Uno. Later non 4x4 Pandas probably had electronic distributors the same as the Uno but I'm not sure.

As for the problems with the engine running, if it is intermittent then it is unlikely to be the cam. A faulty cam would cause poor running nearly all the time. Also a worn cam would probably make 'tappet' noise. Talking of which, also check the valve clearances as this can cause running problems and also indicate whether the cam/ valve seats have problems.

Things to check are the ignition amplifier module bolted to the distributor. Sometimes the wires break up and cause running problems, though normally this shows when it gets warm rather than cold.

Double check as well that the vacuum advance unit is fitted correctly. Make sure the wires aren't trapped.

It sounds to me more like a carburetor problem, maybe a blocked idle jet or a faulty diaphragm? Is yours a carb model or fuel injection throttle body?

The non injection Weber carb fitted to the FIRE is a simple design and it's easy to pull it apart to blow through the jets and give it a good clean. Always use compressed air/ aerosol carb cleaner, NEVER use a piece of wire as you can damage/ enlarge the jets as they are made of soft brass.

A carb kit can be obtained from a FIAT dealer for about GBP 15.00 (I bought one a couple of years ago), and also from Carb/ fuel injection specialists. If you rebuild the carb, clean it thoroughly and make sure all gasket surfaces are clean, check the float height and reassemble carefully.

Lastly, your running problem also sounds a bit like the infamous Uno 'carb icing problem' (check other threads in this forum as it's a well known Uno problem). If it's been problematic only in the cold weather are you sure it's not this? Do you have the metal pipe going from the exhaust manifold to the airbox? Is the heat sensitive airflap in the airbox working correctly?

When it's running rough, put your hand over the carb/ throttle body. If the engine has been running for a while but the body feels ice cold to the touch then it could be carb icing that's causing the problem.

Also, what reading are you getting on the temperature gauge? If it's not warming up correctly then that can cause icing problems. Changing the thermostat is also a good idea as when they fail/ wear the engine tends to run cooler especially in cold weather. I had this happen on my Uno, and changing the thermostat made it warm up quicker which in turn helped reduce icing problems.

Hope this may be of some help to get your Uno back to good health. Stick with it, it probably is only something simple that needs to be done!

Chas

 

[Luke]

You took the sump off and cleaned the crank? Is this easy to do then??

I cleaned the 'top' when changing the rocker cover gasket. The rocker cover itself had loads of gunk stuck everywhere on the inside. Couldn't actually properly clean anything below the camshaft though - there was oil there (I assume that's normal?).

Got a photo of what it looks like when the sump is off?

i think your engine is slightly different to mine, so may be different. I basically stripped the engine bare so yea it was sorta easy. i had to change the head gasket, so got a chance to clean the head. I had to take the sump off to do an oil change as my plug had seized. There was alot of crap in the engine and oil, so i just reconned everything i could get to basically. Worked a treat after


Louie - Thats for all the info. Yea i do have the condesor on the back of my dizzy. Any ideas where i can get a replacement??

 

[Luke]

Chas,
Thanks for your help

The cam & tappets make a racket, sometimes sounds like a bag of bolts but kinda got used to it now over the past year As for the valve clearances, when i last checked they were ok, but i think one of the valves was originally sticking. I did manage to cleana and free it up tho, although may be mucky again.

My car is the carb version. I got some of the spray cleaner and petrol additive to clean the system through. Made a slight difference to it (didnt do it for so long). I had originally thought it was icing, but it does it even now the weather is warmer. I have the metal pipe from the exhaust manifold into the airbox so it has a supply of warm air, and the engine warms up no problems.

i think i may try replace the condensor/amplification module or whatever thingy, see if that makes a little difference.

 

[Louie Bee]

Points?

Hi All,

Louie - Thats for all the info. Yea i do have the condesor on the back of my dizzy. Any ideas where i can get a replacement??

Your Welcome Luke!

Reading Chas’s post are you sure you have points and condenser Luke? FIAT had a habit of changing the distributor speck…

If your sure you got points, I'd e-mail FF's sponsors- Shop 4 Parts click for link to their contacts page. They’ve been good to me!

Don’t forget to buy and change the points too. –

(The porter manual says) most FIAT mechanics remove the distributor before working on it as its much easier. After fitting points and condenser You’ll need to check the timing as you will really struggle to get the points gap if its owt like the 903’s OHC dizzy.

I cleaned the 'top' when changing the rocker cover gasket.

Sounds like you have 1116cc overhead valve engine Edit: 1116 Is also an OHC.
The FIRE engine is Overhead Cam and has a cam cover gasket. The Uno 60 S in 1990 could be either 1108CC Fire or 1116 OHC LOL.

Regards All,

PS Fabio tonight.

 

[whatoncewas]

The Uno 60 S in 1990 could be either 1108CC Fire or 1116 OHC LOL.

Hmm... Does that mean I have the rubbish version of the engine then?

How would I find for _sure_?

Also, does that mean my other thread on what oil may be useless as it's not really a FIRE engine at all?

 

[Trevor]

Hi there,

As far as i know all unos with the FIRE engine from 1986 were electronic ignition so i think it would be a good idea to check the module on the side of the distributor.

Another thing to check has it got 1 of them clear plastic inline filters if so take it off.

Did you say you had the head off, are you sure you put the head gasket on the right way, (ALTO to the top) if it's upsidedown it blocks the oil feed to the head and will damage the cam.

Regards Trevor.

 

[Luke]

Hi there,

As far as i know all unos with the FIRE engine from 1986 were electronic ignition so i think it would be a good idea to check the module on the side of the distributor.

Another thing to check has it got 1 of them clear plastic inline filters if so take it off.

Did you say you had the head off, are you sure you put the head gasket on the right way, (ALTO to the top) if it's upsidedown it blocks the oil feed to the head and will damage the cam.

Regards Trevor.

The gaskets fine Its been driven for about a year since the gasket was changed, and had little problems until recently. Thats why im miffed. The only problem that was always there was the lurching problem.

 

[Louie Bee]

Rocker Cover On Uno 60?

Hi All,

Hmm... Does that mean I have the rubbish version of the engine then?

How would I find for _sure_?

Also, does that mean my other thread on what oil may be useless as it's not really a FIRE engine at all?

Hi ts86, I would say neither are rubbish.

(Porter manual Research...) Only FIRE engines have a square oil filler cap. The 1116/1299/1301/1372 OHC have a sloping cam cover. – Notice edit in my last post lol. – Easy mistake calling a cam cover a rocker cover lol. Hmmm – so only the 903 is OHV

Edit: The 1116 was only for the Selecta (Auto box) after Jan 1990. I reckon you will find a square filler cap and a FIRE Engine ts86 lol.

 

[Chas Uno]

Hey Luke,

The spray can carb cleaner is only so effective. It won't help clearing sediment out of the float bowl so a strip down is often needed else sediment gets drawn back in and block the jets again.

Also, the diaphragms can fail after a few year, so it's often a good idea to strip and rebuild the carb with new gaskets and diaphragms once it gets to about ten years old.

Don't forget that it doesn't have to be freezing temperatures to get carb icing. Once the temperature drops below 10 degrees icing can still occur, as you have to take into account the wind chill factor of air travelling through the carburetor body and also how much moisture is in the air.

However, you say your cam is making a racket so maybe that is the problem after all. Whip the cover off and check the gaps, which on FIRE engines and also non-FIRE ohc is set with shims so need adjusting rarely.

If your gaps are tight, then that points to valve seat recession (wear). However, if your cam is noisy it's more likely that gaps are too large, which would point to a knackered camshaft.

As checking the valves is the quickest and easiest thing to do out of what's been suggested I'd go down that route first. Four bolts hold the cam cover down on the FIRE, and a set of feeler gauges will show you what the valve clearances are.

Once you know the condition of the valves then you'll know whether to try the other suggestions or look at sourcing a replacement cylinder head.

One last thing, check to see if you are getting sufficient oil flow to the camshaft. With good oil the cam should look oily, but you shouldn't have thick black gunge in there. If it's dry then you may have oil starvation problems to the camshaft which would cause the cam to wear quickly.

Let the board know how you get on.

Chas

 

[Luke]

Thanks again chas,
I was considering doing a carb rebuild just needed to source a new gasket and diaphram. Spray + additives was kindof a quick bodge it to see if it made a little difference or not.

As for the oil supply to the cam, that should be getting enough oil now. Thats what my original problem was - I had no oil pressure feeding to the cam (and it had been driven a good few thousand miles like it). It was my grans car at the time, i dont think it ever had an oil change so it was so thick you could spread it like marmite. The oil feeder pipe in the sump was blocked, the channels in the head and block that go from the cam to the sump were mostly blocked, the pump was clogged, but worse of all the distibution pipe in the head (that puts oil onto the cam) was clogged. It all got a good clean with parafin and a blast of air to unblock everything, new head gasket etc..

So the oil should be fine now. Not long done another oil change and it was fine, no lumps bumps or gunge. Head gaskets fine, as is most other things. I think its just where the cam was dead before i got a chance to save it. My grandads version of fixing an oil pressure problem was to disconnect the warning light :bang: So now its a case of trying to nurse it back to health a bit at a time. I wont take it to a garage becuase i want to do the things myself, for experience sake.

Luke

 

[Chas Uno]

No problem Luke, glad to try and help keep another Uno on the road

By the way, if your cam is knackered you might get away with just changing the cam on it's own. Thing is, the top of the valve stems can also wear. If the hardening has gone on the valve stems then they will continue to wear even with a new/ replacement camshaft.

If this is the case it might be better to source a second hand head complete from a scrapyard, but check the cam in the replacement head to make sure it's not also worn. Look for signs of overheating on the cam lobes, this will often show as a darkening/ blueing on the metal surface or obvious signs of scuffing/ wear. Again, check the clearances, as if they are ok and there's no sign of wear on the cam then the head should be a good one.

Good luck with fixing the problem, and it's good to do it yourself. Besides being a lot cheaper than a garage you'll learn a lot in the process, which in turn will make you a more experienced mechanic. That will save you a lot of money in the long run

Chas

 

[whatoncewas]

Edit: The 1116 was only for the Selecta (Auto box) after Jan 1990. I reckon you will find a square filler cap and a FIRE Engine ts86 lol.

*phew*
Thanks though. I can confirm it is the 1108cc engine definately as it says that on my V5 registration document (didn't think to check that before).

 

[unosy22]

sucking air on inlet manifold due to hair line fracture underneith problem goes away when warm because manifold warms up closing the crack.

from my freind fiat uk tech.

sy

 

[Bushboy]

cant really help with ur probs luke but if u wanta new cam, feel free to take the one out of my uno. still sat here on the drive lol, perfect working engine before i took bits off it.