Technical UNO Won't Idle - FIXED!

[Popayetwo]

I have the 1998 model Fiat Uno five door with the 1400cc engine (South Africa) and the weber carb.

The problem started two weeks ago. The engine would cut out instead of idling. Starts with choke partly out and goes like a bomb but simply would not idle. Most frustrating when you get to a stop street or traffic light -- the engine just quits.

Found the fault this morning. The Idle cutoff solenoid was faulty. It is a spring-loaded solenoid that cuts off the fuel at idle when the ignition is switched off so the engine does not run on when hot. But the solenoid was open circuit so it was in the permanently cut-off position when idling. The engine tried to suck fuel from the main jets, cauusing it to surge and then cut out. Replace the solenoid with a good one and bobs your aunty. Or you can replace the solenoid with a blank bolt and do away with its (dubious) function.

Colin Smith
Port Elizabeth
South Africa
20 Sep 2005

 

[F R O S T Y]

I think you mean Bobs ur UNCLE mate lol

F R O $ T Y

 

[Louie Bee]

Welcome to the Forum

 

[(CZ)enda]

Yeah, the same thing happens when you forget to put the wire connector back to where it belongs and leave it hanging free - how do I know ?

 

[alexGS]

As Louie says - welcome - and thanks for the post, it's always interesting to read of a problem solved!

Most of us can only dream of a 1998 Uno.

The fuel-cutoff on the Uno 60 and 70 models that I've seen is supposed to come into operation during over-run conditions with the throttle fully-closed and the engine RPM above 2000 or so. The control unit is attached to the top of the right suspension strut mounting. I wonder if your car has this?

Or perhaps the cut-off is simply switched with the ignition, to prevent the engine running-on when the key is turned off. That seems to be what 45 FIRE models have.

Anyway, I guess a good check for the fuel-cutoff solenoid is to try disconnecting it with the engine running - the engine should stop. Some that I've seen have had the pointed end of the solenoid plunger snipped off with cutters - an even nastier expedient than the replacement with a bolt!

-Alex

 

[biggaitch]

hi everyone just bought a new £60 idle cutoff solenoid for fire 1987 uno and surely it should retract when connected to 12volts ??? my old one seemed faulty so I cut the tip off.it does work ...the new one seems identical it will only retract (off the carb) when powered up by a flick of the finger ..any ideas anyone ???

 

[jackwhoo]

hi everyone just bought a new £60 idle cutoff solenoid for fire 1987 uno and surely it should retract when connected to 12volts ??? my old one seemed faulty so I cut the tip off.it does work ...the new one seems identical it will only retract (off the carb) when powered up by a flick of the finger ..any ideas anyone ???

When it's in the carb is the tip slightly pressed in by the seat in the carb?
Try pressing tip in slightly then connecting to 12v , does it then work?

I think if it holds in with 12v it will pull in when fitted to carb.

 

[biggaitch]

what a great idea.....never crossed my mind.I fitted the new one and the car sounded good for a couple of minutes..now nighttime, but I shall try your suggestion tomorrow and thank you very much for that idea!! Biggaitch

 

[jackwhoo]

what a great idea.....never crossed my mind.I fitted the new one and the car sounded good for a couple of minutes..now nighttime, but I shall try your suggestion tomorrow and thank you very much for that idea!! Biggaitch

No need to remove it from car , if it's working you should hear it click when 12v applied and removed.

 

[biggaitch]

fantastic info...click when ignition on and never run so well!!
I am very impressed with the help received and the result didn't waste my money, because the original I think was playing up . it had done a million retracts over 33 years , so can't complain !! thanks to Jackwhoo and the forum!! biggaitch