AliBarnett said:

This sounds exactly like the problem i am also currently having with my 1.1 ie uno. Wasn't so bad at first, just hung a bit when accelerating, but could over come this by letting off the accelerator and then reapplying it. But now its really bad and the revs will drop off completely unless i pump the accelerator changing its position constantly. If the accelerator is held at a steady position the revs start to drop off regardless of where it is or temperature, which i've noticed is because of fuel being injected decreasing. If i unplug the throttle position switch it will run and idle (although slowly & roughly due to the idle switch not being set properly) normally, of course accelerating doesn't happen very well if the throttle position switch is unplugged, however, if the throttle is held slightly open while starting up, it will run just as it should and accelerate (well the engine at least). The other way i've found of getting to run properly is to unplug the ECU and then replug it in, runs fine for about a mile before getting the same problem.

I have tried changing every sensor to do with the fuel control, the throttle position switch, the idle sensor, the lambda sensor, the coolant temperature sensor, the coil, also changed the distributor, and ignition ecu.
The fact it will run properly without the throttle position switch plugged in suggests that the fuel pump is fine and i have checked fuel flow anyway, but i have changed the secondary fuel filter, and the air filter is brand new also.

I have checked the connectivity with all sensors to the ECU, and they are all fine. The only thing i haven't managed to try changing yet is the ECU itself, and i'm beginning to suspect that this may be the problem. I've ruled out any mechanical problem as it will run fine, as i have said, without the throttle position switch plugged in. The timing is correct, the spark plugs all spark, etc.

The problem started very suddenly, i had ragged it down to wales and back, then up to preston (I was based in warwick at the time), then on the way back from preston when pulling out of a service station, i found it hung rather badly when accelerating, problem continued for about 2 weeks before disappearing almost completely, until one day a couple of weeks ago it came back with a vengance, and i struggled to keep the engine ticking over and only just managed to get back to where i was staying. Here the engine wouldn't start properly, with it starting then dropping off almost immediately.
All experimenting/changing of parts detailed above then took place.

Next thing to try is changing the ECU in my view, but its a sunday, the scrap yards are closed, and i'm not even sure if it uses the same ECU as the 999cc. Really annoying coz i'm in cambridge and need to drive to preston this evening. Any other ideas or inputs are very welcome.

Ali

Additional: Its a L plate and has done 119000 miles.

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1986Uno45S said:

Hi Raz and welcome to the forum :wave:

The 'square thing' that was changed on your carburettor was probably a diaphragm. They last about 5 - 10years and then they perish and no long work with a vacuum. As to your problem, a few things spring to mind.

It could be a fuel starvation problem caused by a blocked breather in the petrol tank or a blocked fuel filter. Next time your Uno stops working when you're driving, take off the petrol cap and then see if it will start (instead of waiting 15 mins). If it does it's a blocked tank breather.

Check the inline fuel filter (if it has one).

If the car always starts fine when cold but only causes problems after you've been driving for a bit (as you say) then the ignition amplifier on the distributor could be on the way out. This is the small silver finned unit that bolts onto the side of the distributor. When your car loses revs and dies again, very carefully check to see how hot the unit is i.e. hold your hand near the unit without touching it. If it is radiating a lot of heat then that means it's running too hot and could be the cause of your problems.

Lastly, when did your Uno last have a proper service?

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