I have a 999cc FIRE UNO n it jerks at around 2000 to 3000 rpm, have got the carb serviced but it hasnt helped. The jerks are even more prominent with the air contidioning on. Please help.

Seems like you have the problem i have, not solved yet though.

ankit said:

I have a 999cc FIRE UNO n it jerks at around 2000 to 3000 rpm, have got the carb serviced but it hasnt helped. The jerks are even more prominent with the air contidioning on. Please help.

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totally off topic, but air conditioning cool

uno_94,

FIAT Unos made in India (brand new) have air conditioning.

ankit,
I think these cars have a fuel cutoff system. The control module activates a valve on the carburettor when the engine is over-running - the control module 'knows' this by a switch on the carburettor that closes when the throttle is fully closed (accelerator released). However, the fuel cutoff only takes place at engine speeds above 2000RPM, which is what makes me think that it may be coming into effect at that speed, and causing a jerk.

Check around the throttle linkage to see if you have a wire attached to the spring-loaded idle speed screw. If you don't, then disregard my message, but if you do (or, obviously, if it looks like a wire could have fallen off there) then investigate whether that wire is making contact when the throttle is closed, and not making contact when the throttle is open.

puttekula,
It's much more likely that this is the problem with your Uno, since I know that Uno 70s came with the fuel cutoff system... Try 'hot wiring' the fuel cutoff solenoid (on the back of the carburettor) to the ignition coil orange terminal (so that the fuel is on all the time) and test drive to see if it makes any difference... if so, suspect that the control unit has failed.

-Alex

Thanks a lot for all the help. Ill try getting it sorted and let you people know what the results are like.