Technical Gear change problem in Uno - from India

[philipreji]

Hello Eeveryone,

Greetings from Bangalore, India! I read the posts here regularly and it’s very useful for me. I own a 1242 cc petrol Uno (SPFI, Nov 2003), which was one of the last Unos made by Fiat India..After reading a book titled “low cost car repairs” by an English gentleman (Miller I think) I started doing some DIY on my own. So far I have changed the engine and transmission oils, cleaned the air filter etc..the car has a hydraulic clutch.

Of late I have a problem with the gearshift: the engagement between the engine and the clutch becomes a bit imperfect once in a while. That is, this doesn’t happen all the time, it is occasional. If the engagement is perfect I can comfortably shift gear from 2nd to 3rd at 15 km/hr, and if it is not perfect then the car will jerk and rattle a little bit if changed at this speed. So I have to wait until about 25 km/hr, to get a smooth gearshift. Even then, while running I can feel that the engine and the clutch are somehow not exactly synchronized, because there is a slight lack of power and pickup.

Another thing I noticed is that if the car is not started for 3 or 4 days and then started on the next day, it performs great, as if it is new! Don’t know whether these are related issues..

My doubt is, if the problem is clutchplate wear, then why doesn’t it happen all the time? Or is it the starting phase of plate wear? Or something else? All fluids in the car are at normal levels, there are no leaks, and the battery is in good shape.

Looking forward to your kind suggestions..

Thank you very much,

Reji

 

[alexGS]

Hi Reji,

and welcome to the forum
Yours sounds like a very nice Uno to have (late-model so rust-free, 1242cc and fuel injected, all things that we can only dream of). I'm pleased you are doing the maintenance yourself - the best way to ensure that it gets done...

I actually think, based on the low speeds that you quoted, that the gear engagement/clutch issue is more likely to be an engine-smoothness issue. In other words, if the engine pick-up is not smooth, it feels as though perhaps the clutch is 'grabbing' when in fact it is the engine that is not providing the power smoothly. This is normal behaviour for the engine if not warmed-up, or more accurately, we would expect some hesitation when the engine is cold compared with when it is warm. You mentioned a 'stand-down' period of several days as making an improvement, which suggests perhaps a fuel quality problem to me - I can't think of anything else that would make a difference when left for that length of time... sometimes the clutch splines are prone to rusting when sitting, but this creates problems rather than solving them!

For the engine smoothness, the usual advice of checking for vacuum leaks (split rubber pipes, tightened bolts on fuel injector etc.) applies.

Anyway, 15km/h is too slow for third gear; I'd have thought more like 30km/h as a minimum. The engine produces its peak torque (turning force) somewhere around 3000RPM. Therefore the engine runs at peak efficiency at this speed. Power (rate of work done) continues to increase up to about 6000RPM, but the efficiency is slightly decreased. The efficiency is also lower if the engine is turning too slowly - below 2000RPM for example the engine will be not producing much torque and car performance would be poor.

So, you should aim to keep the engine between 2000 and 3000 RPM in my opinion...

As for clutch plate wear, the test for this is to accelerate up a hill (with the engine warm) in 2nd gear, running up to about 5-6000RPM... the clutch would start slipping then, if it's going to... slipping is evidenced by an increase in engine speed without the vehicle speed increasing. If there is no slipping, it is less likely that the clutch is worn out.

If there is a clutch hydraulic problem, the first sign is that you find it difficult to engage reverse (the typical fault is when air in the hydraulic system prevents the clutch from disengaging fully, and reverse gear has no synchromesh so the gears have to be perfectly still to engage).

Hope this helps and that someone else can point out what I've missed...
-Alex

 

[philipreji]

Hi Alex,
Many thanks for the welcome, and your detailed reply - being in this forum really helps me!
In fact Fiat India did not make many SPFI Unos, so I’m one of the few guys here having this model! In 2003 Dec they stopped making Unos altogether. Fiat was in bad shape here until recently, and then they joined hands with the Indian auto giant Tata which seems to have helped a bit.
Regarding the engine temperature issue you mentioned: in fact on some days, the car is perfectly fine in the morning when I start it for the first time, and after driving for say 10 km, this “imperfect engagement feeling” may appear. On some other days it can be the other way! In addition to changing transmission oil I had also greased the clutch linkages, including that part under the rubber cover, but these measures don’t seem to have much of an effect. My car has run only 12000 km so far.
Then I had done a “new” type of clutch bleeding..I just opened the clutch fluid reservoir cover for about a minute, and then closed it. My logic was, if there are air bubbles in the fluid, there is a small chance that it might escape, even though the fluid is thick..and it worked! For several days after that, this “imperfect engagement” problem didn’t appear at all! I myself am surprised at this..have you ever noticed something like this before?
Another thing I found is that the fuel quality is very important, for mileage as well as engine smoothness.most of the fuel we get in India is adulterated. However there is a “Shell” outlet near my home which sells pure fuel, and I tank up from there. The mileage actually goes up then (I get 13 km/lt in city and 20 km/lt in highway, with Shell).
Thanks,
Reji

 

[premrajeev]

Hellow Reji

Welcome to fiatforum.

Sorry didnt notice your post early enough.,

Well It's wonderful to know that u own one of the latest uno's in this country.
I owe a 1998 1000 cc one, carburetted though.

I managed to get around 16 KMPL now, under restoration now, will have to check the milage/tuning again :

Alex, do u think SPFI is better for fuel economy when compared with a carb.engine ??

I am going to try the max i can get from this car : just for sake..well I'm a guy who needs some power at my foot

I should have turboed it but hell it's not available here :

One of my cousin stays in UK so I may still try to get one shipped to me...:idea:

 

[alexGS]

Alex, do u think SPFI is better for fuel economy when compared with a carb.engine ??

In theory yes; in practice it makes little difference. I've only experienced a ride or two in Louie Bee's 45 with injection. I think it solves some of the cold starting/running problems (hesitation etc.) but it doesn't liberate any more horsepower (at least, according to the specifications) as it's just a single-point injection so not really much different to a carburettor; just more 'automatic' for starting. Of course, I haven't owned one so you can take my advice with a pinch of salt...

-Alex

 

[Chas Uno]

If the SPI Uno is fitted with a CAT it is more likely to have worse fuel economy than a carb'ed version. CATs sap power meaning the engine has to be worked harder increasing fuel consumption, especially on older cars where they were fitted after the original pre-cat engine design came out.

One advantage of the carb'ed FIRE engines is a manual choke, so you can close it off sooner than the ECU SPI models. In theory this will make them more economical! But of course, if you keep it open longer it can have worse economy.

I prefer the carb'ed versions, but I may have to retract that statement if I start getting icing problems now that the weather is turning cold...

Oh, and if you have a carburetor Uno then you have greater scope for improving the intake side for performance than with the SPI. A twin choke Weber will fit with an adaptor

 

[premrajeev]

oh really,

havent seen a twin choke carb till date,knew they exist ,but is it so useful for increasing the power and if yes by howmany horses ?

 

[antsuno2]

my old fiat 127 1300 gt had a twin choke carb and oh! did it fly 75bhp but felt like more, try and find out, which may fit yours

 

[philipreji]

Hi all,
Sorry I couldn't check Fiatforum for about a week and hence didn't see the latest discussion..
Thanks for the welcome Prem..I have heard that the 1000 cc carburetted is a great car, but not driven one yet..I am sure you will be enjoying it..
My car has a catcon with it, and the mileage seems to vary with the petrol I use. In bangalore city traffic (which is really horrible) I get about 11.5 km/lt with usual petrol, while about 13 km/lt with Shell Normal petrol. In highway (trip from Bangalore to palghat - about 400 km) I have got about 20 km/lt (with usual petrol) which is really good!
I like the SPFI because starting in the morning is problem-free. However my brother-in-law has an Uno diesel, and that beast seems to have much more power under its hood compared to the petrol version (of course it is a 1.7 Lt engine).
One thing I dislike about the SPFI is that I am a bit afraid to play with the throttle body..carburettors could be played with I guess..
cheers,
Reji

 

[premrajeev]

reji,

Well so I guess u r from Kerala. Me too. but now settled at Bombay. My brother is working in Bangalore,So quiet familier a place.

The problem with Injected engines is u cant adjust the power/idlespeed/milage etc as they are being controlled by a Microprocessor.

The adv.of carb is that u can really tune /detune your engine by messing with the carb. (the carb in uno is not a silly one ,though - u must know what u r doing unless u will end up messing your ride.

I have a huge sub and accessories weighing around 20 kgs, and me myself is 95 kgs,hope u must be quiet impressed by my milage figures.

 

[philipreji]

Prem,
Yes I'm from Kerala but working in Bangalore for the last six years. So you know about the bangalore traffic! It is going from bad to worse.
My experience with carburettors is limited..used to do some cleaning in my previous Premier Padmini (Fiat 1100 D, 1972 model!) which I owned before buying the Uno. The Padmini's engine bay is very simple and spacious, and it's a great car too.
Your mileage figures are impressive, no doubt. Please let us know about the changes you observe after finishing the restoration work..
Reji

 

[premrajeev]

Reji,


hope u r keeping an eye on my rebuild thread ..
https://www.fiatforum.com/uno/82671-quick-rebuild.html

more news of the rebuild on that..