(G) Uno 999cc or 45 carb tuning querie

Question..


My car just came back from some idiot who fidled with the carb
he reckons he knew what he was doing and now im suffering with poor fuel consumption

around 350 to a tank where i used to to 600 odd

does anybody know the stock settings for the fuel/air jets ?

i do have the manual .. but i cant seem to find it in there ...


firstly what screw is what??

I have a top screw and a side screw


Turning them clockwise i would asume means making them richer or more air, cos the screw would be coming out?


please guys this is urgent , its annoying the crap out of me .

Unfortunately I have to start with more questions... Is the car actually running any better or worse apart from the fuel consumption? Are there 'flat spots' - do you have to push the accelerator harder than normal?

Is the choke being used - with the air cleaner housing off, can you see the choke flap fully open? Is the engine reaching full operating temperature (middle of the gauge?)

Is there misfiring? Have you checked the ignition timing and vacuum advance (more likely to cause excessive consumption)? Spark plugs looking OK? (mxture too rich would quickly give blackened plugs. Some carbon around the edge of the plug is normal, but the central insulator should be clean).

Even the cam timing could be off by one tooth, particularly if the cambelt has been changed recently. The cam pulley line corresponds to a notch in the cylinder head at approx. '18 minutes to the hour'. This is with the engine at TDC (crank pulley or flywheel lined up with the mark nearest the front, on the cambelt cover or clutch bellhousing respectively).

That is indeed pretty bad. I would expect the engine to run really badly if the carburettor was solely responsible, but you haven't mentioned any symptoms. Check the tyre pressures also, brakes not binding? Try pushing the car on a smooth flat surface.

Idle jet has '47' marked near the tip. Main air corrector 165, Main jet 105. It is not possible to swap jets by mistake on the 32 TLF, so these numbers are not going to be much help to you, as your expert tuner may have drilled the jets out

Not in the handbook, but it is in the Haynes manual, Chapter 13 (Supplement), which is half the manual. You can possibly download the relevant info from http://www.unoturbo.za.net .

The 'top' screw I presume is actually the one mounted on an angle (approx. 45 degrees) with a hexagonal body. This sets the throttle plate opening = idle speed.

The 'side' screw is on the base of the carburettor, pointing towards the right side of the car (viewed from the driver's seat). This is the idle mixture screw. Note that it does not have much effect with the throttle open at higher revs. Mixture at these speeds is more a function of air leaks (if too lean) or blocked air filter (if too rich).


The idle screw - turn anti-clockwise to decrease engine idle speed.
The mixture screw - turn anti-clockwise (screw coming out) to lean out the mixture (more air). Go around to the back and listen to the exhaust - if too lean, it will be 'missing' and the speed will probably be stumbling. If too rich, it will be 'chuffing'.

Fair enough, with petrol prices the way they are!
Hope there's something helpful that I've suggested... but please note (if you hadn't picked up already) I suggest that if the engine is already running smoothly, trying to adjust the carburettor will probably make things worse rather than better. You really need to reflect on how the car is running (and of course, how it is being driven), and check all other aspects of maintenance. Maybe also check the consumption on a long trip by way of comparison.

-Alex

Wow! Bro thank you for that reply , i never thought that anybody could EVER be so helpfull on a forum , thanx mate

the car goes okay , she runs perfect , when starting in the morning with the choke out she splutters abit , but a couple of revs to get the throaght open gets her running . then i usually drop the choke a little back . she will jitter and jerk abit but a couple of hard accells sorts her out.

running temp is around 1/4 .

The thing was , i used to get about 20km per litre . but the car was lean and the was pinking due to the octane drop in the local fuel .

i took her to be retuned , had the timing retarded , and since then the car has been horrible on fuel .

the guy did adjust the screws , top and bottom one , took it around the block and said i could go .

the car was so slow , i could do a max of 60mph or around 100kph , i took it back the next day , with green vains coming thru my skin , Notice the hulk , lol . he readjusted it and she went much better . but my fuel consumptions is still very bad ..

anything else i should be looking at?

If the timing is very badly out then it can cause excessive fuel consumption. I'd get this checking (2 degrees BTDC if I recall correctly) and then take it from there. The carburetor is the LAST thing that should be adjusted when doing a tune up, so get the ignition side checked first.

Also, are there any modifications to the engine? Fancy air filter or anything/ What exactly did the garage do when it 'tuned' it? Knowing this would help!

Oh, are you talking 350 miles or kilometers per tank? 350 miles is quite normal!

Yes I agree with 1986Uno45S (Chas), the one thing that stands out in your post is the "had the timing retarded" part - this will really hurt the fuel consumption on the 45 if it is still wrong... the spec varies slightly between different years. 2 degrees in the handbook I have, Chas remembered correctly of course

I'm sure that I've seen 5 degrees quoted somewhere though, and S.A. versions may even be different (with the high altitude of Johannesburg, though Cape Town is obviously more like sea level!)

But anyway the most important thing is that there should be, say, 2 degrees advance WITHOUT the vacuum advance connected... when you connect that pipe, the idle speed should increase noticeably as the total advance will be 12-ish degrees. Some mechanics are unaware of this, and that would explain the ignition timing being too far retarded...

About the pinking. See if you can buy a fuel additive (obviously, needs to be reasonably cheap!) from an automotive parts store... or possibly try to adjust your driving style (I mean that in the nicest possible way ) since either of those will give better economy than retarding the timing.

Your adjustment guy obviously tried his best, but these small engines really don't run well on low octane, full stop. I think this is mainly due to the high-ish compression ratio and the flexible nature of the engine that tends to encourage high-geared use.

Finally, when we talk about 'local fuel', is it 91 RON (Research Octane Number)? 95 is the minimum specified for the Uno (all engines). Our petrol comes in 91, 95, and 98. I never had much luck with running the FIRE on 91, it tended to be lumpy when driving slowly as well as the pinking issue. The 'clean, green' 98 is more than necessary and makes no noticeable difference except that once or twice, spark plugs fouled up...!

Cheers,
-Alex

well well,

i broke a spark plug the otherday after i was told , it was replaced when they serviced it . anyways , had the timing set at the agents , no luck in having them tune the carb .

the car is stock bog std except for a mildly free flow exhaust . about 50mm in diameter , it sounds like a damn golf but anyways .

she does about 140kph on the flat road with 15 inch alloys . if i push really hard around 155kph in 4rth?


still not too friendly on fuel , sigh any other sugestions?

howzit bro, nothing wrong with the settings on the cabby, it's the new **** LRP fuel, also got roundabout 16-17 km/l, now I'm stuck at 10 - 12km/l. I use Unleaded in my uno, as it gives me better fuel consumption and performance than the ****ty LRP.

hey bro , yeah i agree , but i was having the good fuel consumption on lrp . i run Unleaded now , and i do get better fuel consumption .

i she was running abit lean , i richend her up , and shes flying now . or it could be the gale force wind from behind lol , manticore , why didnt you come to the uno turbo weekend last weekend , it was the bussiness!!