Fuel pump pressure

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Nelly
Posts: 655
Joined: Wed Oct 22, 2014 6:47 pm
Location: Hampshire

Fuel pump pressure

Post by Nelly »

To return another lost thread:
Nelly wrote: Spring is here so Nelly is coming back out the garage - and we now have time to look at her intermittent stalling when idle issue.

While the battery was on charge I checked the fuel pressure from the pump. It's around 2psi. Does that sound ok? When turning the engine on the starter we got a reasonable trickle of fuel from the pump every other rotation.
Nelly wrote:Neil Evans It's camshaft driven so it will only be every other rotation, though you should get a good spurt rather than a trickle...
Nelly wrote: Hard to decide what constitutes a 'spurt' rather than a 'trickle' :D

But probably got a couple of teaspoons of fuel flow out the pipe on each second rotation. Sort of ran out rather than coming out with any sort of force.

Although if this is causing the intermittent stalling is this likely to happen when the car is idling (as it has) or when the engine is under more load? Vapour-lock perhaps?
Hurtzberg wrote:Definitely a spurt. When cranking mine in gear to pull it up the drive with the carb disconnected, it half filled a 4pint milk bottle in the space of about 15 yards.
Nelly wrote:I'll look at reconditioning the fuel pump then. Although, new pumps are pretty cheap, and it would give us a spare if needed too. Are the midget fuel pumps the same? 17H98 like this one: http://mgbhive.co.uk/product/midget-fue ... 1958-1963/
Neil Evans wrote:Looks the same, though will say that it appears to be a modern copy that's probably made in China so you may be best overhauling the one you have already. They were designed with reconditioning in mind...
A40FARINAGURU wrote:have you tried Tim & Matthew to see if we have one in stock?
Edosan wrote:and you can definitely buy replacement diaphragms, which is the bit that is most likely the problem for £10 exchange from Tim and Matthew
Neil Evans wrote:Before you jump in, test the pump as the problem is more often than not a blocked fuel tank outlet or issues with the fuel line itself ... Remove the pipes from the pump and swap the short, pump - carb link pipe to the other hole, pointing downwards into a receptacle of water. Crank the engine over now and see if you get the same response... If you still only get a trickle the fault is probably with the pump, though it may be something as simple as a blocked gauze filter...
Thanks all for your help..will give it a try.
Felicity and Sam, Owners of 'Nelly', 1955 Black 4-Door A30
Owner and Club Member Since 2014
Southampton & New Forest Club Member
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