Technical UNO Idling/running problems

[snitter]

Hi. My UNO is driving me insane!

Starts no problem. As soon as it gets warm, the idle goes all over the place. up, down & the invariably stalls. The car will hesitate when driving, & usually stalls when I stop at lights. Sometimes it will not start straight away. The car seems to be fine when first started for a few minutes, it only seems to have problems when it has warmed up.

Things I have tried so far:
1. Replaced the vacuum advance unit (side of dizzy)
2. Checked the vacuum pipes for leaks - as best I can
3. Put injector cleaner in the petrol
4. Changed plugs/cleaned dizzy cap/rotor arm

Car: Fiat Uno 1.0 ie 1993. Single point injection

Please help as I may have to take a sledgehammer to it if it goes on much longer.

Many thanks

Mark :worship:

 

[AliBarnett]

I had this trouble a few years ago with one of my uno's. Would start up fine seemed to be no problem, but started cutting out unless high rev's were maintained. Fixed the problem by replacing the cip on the underside of the distributer. Don't buy a new one, no doubt it will cost a bomb, go down a scrap yard and take one off another uno. Is a very easy job to do.

Well that would be my first option, try that, if that fails could be a multitude of other things, but isn't everything!

 

[SuperUno]

What did the plugs look like when you changed them ? If they were black ans sooty, then the coolant temp. sensor is either not working or the wiring /connector is not working properly this could cause these problems especially the warm up issue.

 

[Morty Mort]

Hei.

This is the SPi (Monopoint) Bosh injection /carb. hybrid. Behind the injecton module / throttle body there is a plunger which is depressed every time you let your foot off the pedal. If the throttle wire is too tight, this plunger will not engage, and hence not halven the amount of gas injected into the carburettor (throttle body). Remove the filter housing and look into the carb. If it is diry, clean it with some WD40 (always have WD40 in an Uno) until it becomes white. Start the engine and watch petrol spray onto the white surface. Check if the idle plunger is depressed. If not, then use your finger to engage it and watch the fuel halven its intervals. Establish a new setting of the throttle wire with the two nuts right before the snail-house looking thing to the left of the throttle body. If this seemed to be working alright already, a good clean with WD40 might solve this anyway. Also remove the thermostatic flap inside the airbox filter housing in case it is stuck on hot. This has no function whatsoever on an injected FIRE engine. My Uno started at -25 C without it every time. Did you change your air filter? Then remove the oil breather hose from the rocker cover to the air filter box. Remove the brass filter inside to check if it is clogged with hard oil. Clean it. This will help the engine breathe. This air goes straight into the engine again. It has no particular function other than to contaminate the throttle body.

The idle plunger problem will cause the car to stall on a red light, as it gets choked by excess amounts of fuel.

Morten.