Appia power loss on motorway

[will]

I agree with Charles 'It sounds like fuel vaporisation' I have a electric pump in parallel to mechanical pump on my Appia I just use it to start the car. Recently I have had similar symptoms on hot days with my Appia. I have used the same fuel pump set up  on the B20 and was stuck on the M25 for over an hour the car never missed a bit. 

[Jaydub]

If it only happens on a prolonged run it points to a blocked fuel line so that the pump can`t maintain the full flow of fuel to the carbs under high demand. You normally get vaporisation while stationary or moving slowly due to less airflow/cooling under the bonnet.

[Richard Fridd]

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!

Sounds a good idea. Do you have photo of how your parallel pumps are mounted, as I have seen some professional looking brackets/ banjo type fittings for cylindrical style twin pumps.

Richard

[will]

On the Appia I used a bracket from a BMC car but you can buy https://www.ahspares.co.uk/austin-healey/performance-parts/fuel-boot/double-su-pump-fitting-kit.aspx?gclid=eaiaiqobchmipiu9wcl78givbovtch0hiaqueaqyaiabeglenpd_bwe

For many years I used a SU pump from the scrapped BMC car mounted in front of the radiator where it keeps cool with two T pieces either side of the fuel pump so that the electric pump is in parallel.  On the Aurelia there is a facet pump that bolts on to the inner wing in front of the radiator.

[GeoffJohnson]

Hi Richard
Sorry, I'm late to the party here. I had a similar problem on my Fulvia some while ago. On an SU pump under the cap are a pair of make and break electrical contacts and these required adjustment. They were causing the pump to get hot and vapourise the fuel.Replacement contacts were available from SU (as are pumps , but pricey).

Geoff Johnson

[chriswgawne]

Sounds like fuel starvation to me tbh. Maybe a blocked filter in the tank? Alternatively the pump may not be pumping enough fuel at speed due to internal valve problems. In my experience fuel vaporisation only occurs when stationary or moving very slowly - at speed everything should be cool enough with the airflow?
There are many other possibilities but I would have thought these were the most likely.
Chris

[richardlewis]

Hello everyone, all good stuff to consider, sounds likely it's the fuel pump, so will direct my friend accordingly, plus checking the fuel lines.

[Sebastien]

Sounds a good idea. Do you have photo of how your parallel pumps are mounted, as I have seen some professional looking brackets/ banjo type fittings for cylindrical style twin pumps.

Richard

Here a picture - enjoy!
I think I can trust the fuel pump now!

PS: I notice it is my 500th post, since 2007....

[Neil]

Impressive, I hope the fuel hoses E10 safe

[Sebastien]

Good point - ideal would be to go back to original, only solid fuel lines, Nivex vacuum and no electric pumps.....