I'm having a problem with my 750 panda. When it gets out on the motorway, after a few minutes of running it begins to lose power. When this happens the speed slowly drops from say 75 down to about 40 at which point I pull over because its because its becoming hazardous to other motorists being that slow. After a minute of idleing on the hard shoulder the power seems to return and I can drive off and full speed can be achieved again for a few minutes only for it to return again.
Has anyone had this before on their panda?
The only thing I can think that could be causing this is the fuel pump?
It just feels like its kindof running out of petrol even tho I've got a full tank.
Is it possible that the fuel pump cant supply enough fuel to feed the engines demand at higher speeds and so the carb reservoir is running out? If I drive down the motorway at a steady 60mph with a very light right foot, it doesn't seem to trigger the problem.
Many thanks for any ideas.

I would agree with you if its ok at 40mph then you push to 60mph the she starts to die on you the it does sound like fuel starvation also check air filter it not full of crap also check fuel filter if fitted or even replace they are cheep enough. If you have checked that lot don't forget the filter at the end of fuel line when it passes into carb it is housed just in the neck of the carb petrol feed

I agree with Allen. Sounds very much like fuel starvation. I suspect the filter might need replacing. What reg is it? Does it have a mechanical fuel pump? I'm not sure if the later 750's had electric pumps. Might be a prob with that?

Jon.

Seeing the time of year it is and how cold it's been outside, the symptoms also point to carburettor icing. This is more likely to occur at high speed/ wide throttle openings as you're increasing the air speed/ chill factor of the air passing through the carburettor. That might explain why at lower speeds it's less likely to occur.

Is the little silver foil tube fitted between the exhaust manifold and the front of the airbox present? Also take off the front section of the air filter and check to see that the thermostatic flap (where the hot air tube directs air to) is connected and not lose.

I used to get carburettor icing regularly in my first Uno (same FIRE engine as the Panda) until I realised the little silver tube mentioned above did actually need to be present...

I've just replaced the see-thru fuel filter just before the carb so its not that, is there another fuel filter in the system somewhere that could need changing?
Does the fuel pick-up pipe have a gause that could be blocked?
Could the pump simply be not pumping the fuel fast enough because its worn?(the car has just reached 100,000 miles.)

I'm running a KnN bolt-on-carb air filter (nearly new so not blocked) so no airbox and silver heat pipe.
hmmm....

yes I'm pretty sure the pump is mechanical because its bolted onto the engine with no electrical wires attached.

tashman said:

I'm running a KnN bolt-on-carb air filter (nearly new so not blocked) so no airbox and silver heat pipe.
hmmm....

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I think you've just discovered the problem

I ran a K&N on my Uno FIRE, but only from about April to November. If I ran it over winter I'd get carb icing problems constantly. Stick your standard airbox back on with the heat pipe and the chances are your losing power problems will disappear

tashman said:

yes I'm pretty sure the pump is mechanical because its bolted onto the engine with no electrical wires attached.

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If it's bolted at the back of the engine near to the distributor then it is mechanical

Here's my engine with a K&N fitted - carb icing on demand in the winter!

Yep 1896Uno45S has given the perfect answers I would say, even with a normal airbox without the metalic pipe from the manifold you get carb icing and the symptoms are that of fuel starvation.

Thanks guys - so what exactly is carb icing? Does the petrol spray actually solidify in the carburettor?
It was a few degrees warmer today and I didn't have any problems so I think you must be right. Thanks.

Yep the chamber is so cold when driving that it turns the moisture/water in the fuel to ice. As soon as you slow down or stop it turns back to vapour with the heat from the engine.

Alan.D said:

Yep the chamber is so cold when driving that it turns the moisture/water in the fuel to ice. As soon as you slow down or stop it turns back to vapour with the heat from the engine.

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As Alan.D says, the freezing temperature in the carburettor (due to the factor of the ambient air temperature + the speed of the air travelling through the carburettor body (wind chill) = well below freezing!) causes any moisture particles in the air to turn to ice. These then block the jets in the carburettor, of which the smallest is the idle jet - this is why the first symptom of carb icing is the car stalling when you take your foot off the throttle. The longer you drive it with carb icing occuring the worse it gets until performance across all throttle openings is affected. At this point even the main jet is starting to ice up.

At worst I found my car wouldn't even run with full throttle and I had to pull over at the side of the road with a dead engine. Trying to start the engine again produces nothing, but leaving it for a few minutes and as if by magic suddenly the engine would fire and run as if nothing had happend. This is caused by the heatsoak from the engine warming the carburettor with the engine stopped, until such a point when all the ice crystals are melted and the carburettor will function correctly again.

Thing is, drive off in the same ambient air temperature and it will just happen again. I remember a few journeys where I had to stop and start many times until I realised where the problem lay That little silver foil tube really does much more than just look pretty!

1986Uno45S said:

That little silver foil tube really does much more than just look pretty!

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As they say, eveything has a purpose, although until now, I did wonder that the foil tube does. Learn something everyday!