Technical FIRE running badly

[Toby Brown]

Hi all,

My 86 999cc FIRE has developed this problem where it runs fine for a while and then all of a sudden it loses all power and I have to pull the choke right out just to keep it going. With foot flat to the floor it will get up to about 40kph but is shuddering and spluttering away. I did think it only happenned when it had heated up, but the other day it happened to my partner when she just started it up after sitting for 8hrs...

About a year ago the ignition module was replaced and I also replaced some other part in the distributor that the mechanic suggested, but it doesn't seemed to have helped..

Any thoughts would be greatly appreciated!

Toby

 

[Hyperspace]

It could be the module again, I have seen a few people who got units that just didn't last. If you replace it, make sure the electric contacts gets cleaned first, I wonder how many of these problem units are just cases of coroded contacts. The metal oxidises over similar to the way the headlight tabs do....

Alternatively, the distributor may have not been tightened enough, slipping and screwing up your timing. Always make sure the position is marked at the base so you can return it to that specific point without tools.

 

[alexGS]

As well as the above, I'd suspect a blocked jet in the carburettor. Take off the air filter housing (one 10mm nut and a metal clip at the front), then in the round top of the carburettor, you'll see some brass 'screws' - these are the jets. Be careful not to damage the top of the large one when you remove it - the hole is a calibrated size (air corrector). Anyway, take the jets out and ideally blow through with compressed air, or at least fish out any debris you find.

Consider installing a fuel filter in the hose that goes to the fuel pump (conveniently found on top of the engine).

-Alex

 

[maxi26]

Guys while we on carburetor topic(somehow), dont mean to steal your post Toby Brown, since and before i overhauld my uno 1100 my top speed was 129km/hour (pathetic hey?). Is this realy the best i can get out of my car? Is there no other way to fine tune the carburetor for more performance? just asking. how much do you guys get for top speed? thanx bytheway, my friend gets 160km/hour with his i did not believe it till i drove it myself!

 

[Hyperspace]

Top speed could be affected by something as simple as an incorrectly set float. My carb is about 17 years old and the diaphram in the petrol pump part of the carb was also quite swolen.

Do you know which carburettor is on your uno... they came out with quite a few models.

 

[maxi26]

Thx for ur quick reply Hyperspace, i know its a Weber, not sure of the number. will get it tonite. so in general, if i get a new carb i would be able to gain more speed? their pretty cheap here, around R500-R850 at autozone or cymot.

 

[Hyperspace]

Well unless you know how to set it up, it won't make things any better.
I replaced my carb about 2 weeks ago, and it took a bit of fidling to set it up to be better than the faulty one it replaced (leaking feul shaft).

There are very few settings, on the common 32/tlf 25x.

Basicaly there is the anti-flood, which opens the choke a little after the engine is started on full choke. I think it should be between 4 and 4.5mm.. It is adjusted by tarning the screw in that saucer looking dhingy right at the back against the firewall, the distance is between the back of the carb and the choke openeing when you fully push against the mechanism.

The other three stettings for the 2 exremes of motion in the float as mesured from the top of the gasket (carb needs to be stripped down to second part from top). Incorrect setting could affect either end of the acceleration curve depending on which side you screw up.

And lastly there is the fast idle adjustment for which you need to remove the carb completely as it is the very bottom valve opening you are setting. Measure the gap using a 0.7mm drill bit, as that is how small it should be (give or take 0.05mm).

Then of coarse you need to set up mixture and idle screws. If you are in Europe you most likely have a lead cap over the mixture screw (legal thing).

Also before playing with carb, make sure there are no vacuum leaks.
with the engine running and airfilter assembly off, trying to avoid spraing into throat of carb, spray carburettor cleaner slowly and systematicaly on all the gaskets around the carb, as well as both shafts top and bottom, then move on to the intake manifold, and spray all along the gasket. If any point makes the engine rev faster, you have our leak.

 

[maxi26]

WOW !!! good advice there bru, i appreciate your efforts/sharing...

 

[Toby Brown]

Thanks Alex, I cleaned out a miniscule amount of gunk from the jets and now it runs fine!