Appia power loss on motorway

[richardlewis]

Hi everyone , I have done 1000 miles in my car now. Mostly a 70 mile round trip to and from work , mostly on the motorway.
However, today it misbehaved on the way home, lost power intermittently, didn't feel like misfiring , more fuel blockage somewhere ?
I had to limp from layby to layby , it was fine idling and revving at rest , and a couple of times I switched the engine off.
Each time it started again perfectly , but after a half a mile or so started doing it again !
When I turned off , relief ! onto local road , the problem seemed to go away, and I made it home without any further difficulty, perfectly normally.
It has done this before just very slightly , each time after being at speed at the end of my journey , say, 25 mins at speed.
Any ideas anyone ? It has been going so well , I was going to ask my local guy to make sure all fuel lines, filter, carb clear, but seemed a bit odd as problem seemed to be specific to going at spped for a while , can't understand why it clears when slows down ?
Could be any number of things I guess....
Richard Lewis , Newbury

[Dikappa]

My best guess would be indeed fuel blockage.  I once had an appia that 'sucked' some dirt into the fuel line over and over again, at last we took the tank out, cleaned it in the very professional way (throw some grit in, bind to a cement mixer.....) with very good results.
 

[peteracs]

Hi

Sounds very much like limited fuel delivery.

Peter

[GG]

if not fuel, check condenser and coil. I had a long-term issue with B20 and when warm, it wouldn't run. Thought it was fuel, but turned out it was a coil misbehaving in the heat.

[Charles]

It sounds like fuel vapourisation. it was a hot day I think.  I have an electric fuel pump (in addition to the mechanical one) which I use just to start the car by priming the carb before pressing the starter.  Anyway, I have had the symptoms that you describe and a quick flip on of the electric pump and all is well again.

[mikeC]

When I first got my Appia I experienced exactly those symptoms; turned out to be the radiator shutters which were not opening - disconnecting the link to the thermostat and manually opening the shutters cured things and I have not experienced the problem since.

That may not be your problem, but it certainly sounds like excess heat and the consequent fuel vapourisation.

[Sebastien]

As you describe it, doing it after 25 minutes at speed, it does not come from overheating in traffic!
A mechanical fuel pump does not turn bad in such conditions, then works again.
Would try, as GG suggests, to switch condensers, and coils.
I have had same experiences with my B20, and also other cars, and a new coil solved the problem.

[brian]

When a dodgy coil on the B10, I could not restart as quickly as suggested in this case so does sound a bit like fuel to me.

[richardlewis]

Thanks everyone for your input !
The car has an electric fuel pump that has been excellent so far,  later in the evening I went for a short drive and the pump took way longer than usual to prime , ie 30 seconds rather than the usual 5 to 10 seconds ?
It did the same thing a bit , but didn't go too far or fast, it was indeed a hot day, but couldn't really see how that ought to be an issue, but I don't know much about these things as you all must already realise !
It could indeed be some random characteristic of my car, it only really seems to happen after 20 to 30 mins on the motorway....so the heat/ vapourisation could be the problem.
I will try it again soon during dry weather... I am determined never to get it wet . Fingers crossed might be fine when the weather is cooler.
The joys of owning an old car !
All the best Rich....

[richardlewis]

PS , I did indeed change the coil a few weeks ago , found a brand new original on ebay , so might try swapping it back , nothing wrong with other one , but re other thread I thought it was the cause of the buzzing , which of course it wasn't !
However if it was the coil , wouldn't there be loads of unburnt fuel/ smoking etc ?? i dunno.... anyway trying not to lose sleep over it, the car does actually still go, even if i have lost a bit of confidence in it for longer trips atm

[williamcorke]

Could the fuel pump have a lower supply current that might cause this problem (longer to prime)?

I had a problem with a Flavia where the electric pump was live and buzzing but with lowered fuel pressure. The culprit was the fuse which has a bad contact, reducing current. Cleaning the contacts resumed normal operation.

[mikeC]

The fuel pump taking longer than normal on start-up suggests to me that the carburettor was empty; in other words, all the fuel had either evaporated or drained out. It all points to high under-bonnet temperature and fuel evaporation; it might be worth checking that the timing is not retarded.

[Sebastien]

I also had an electric fuel pump go bad 3 years ago - symptoms were erratic. Carb ran out of fuel, then everything was fine for an hour, or a day! After checking everything else, only the pump remained as a possible cause (it was however still making all the right noises!).
After changing it for a new one, problem was solved. Since then I have put two electric pumps in parallel and can switch from one to the other. On that Lancia there is no mechanical pump!

[richardlewis]

Food for thought , it could be the fuel pump I guess ! Anyway my mate will look at it and investigate in a week or so , but might just try it again on shorter journeys around Newbury for now.
Many thanks for all who have replied, still love it despite recent hiccup....get admiring( I think) glances when out and about.....it has been described as a Noddy car .....but I think it is cool !
Still would like to get rid of that buzzing .... might have to bite the bullet and get a specialist to look at it , Omicron , but such a long way away ! Unless anyone else knows anyone nearer to me. Sounds like it could be a bush in the drivetrain somewhere... as suggested ..at least it all but disappears on the motorway ....when not breaking down ...lol

[Neil]

If you have an electric pump, check where the +ve feed is connected, if it connected to the coil where it is switched via the ignition you might find that to be a problem from experience with a Fulvia fitted with that arrangement, power feed re-routed to another source and the issue was resolved, but it took a while to find that as the cause.