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MG Midget and Sprite Technical - Facet Fuel Pump

I replaced an SU pump on my midget shortly after I bought it 10 years ago. I've got used to the ticking behind my right ear and it gas never failed. Recently it has developed a very loud tick after start up as though it is starved of fuel. Eventually it quietens down but can start again when running and it seems to be worsening. I can't see any kink in the pipe and most of it is metal tubing. The Facet is mounted on the off side of the car in the boot about 6-8" up from the boot floor. Is it starting to fail or do I have a blockage somewhere. Any ideas would be appreciated.
W Clough

I have the same situation, but it's not done it recently. I first noticed it after a run when I got back home, it was ticking louder than normal, but the next time I ran the car it was gone. Mine's been on three years and 3,600 miles and has been performing OK, but you do worry that it's going to let you down at the worst moment. Sorry I can't be of more help. Maybe they're all like that but are not breaking down. Just one of the joys of owning our little cars I suppose.

Bernie.
b higginson

Constant, rapid ticking of a SU fuel pump (Facets do it all the time) is an indication of an air leak on the inlet side of the pump, not a clog. The leak can be the result of a hole in the pickup tube inside the tank, a loose connection between the fuel line from the tank to the pump, a hole in the line or a leak on the inlet side of the pump itself. To isolate where the problem is, run the outlet side of the pump into a glass container and turn the ignition on while watching the stream of fuel. If it is full of bubbles, an air leak exists. You can then run a flexible line from the inlet side of the pump into a can of fuel and repeat the above test - no bubbles means that the leak is somewhere between the pump inlet fitting and the tank (bubbles in the stream means that the problem is in the pump. Working the flexible line back to the end of the line that attaches to the tank and repeating the test will check out the fuel line. If everything checks out good, reconnect everything, making sure that all the fittings are snugged up tight may cure the problem. Cheers - Dave
David DuBois

Hello David,

I thought I had seen you talk about a check valve somewhere that would cause the rapid clicking. Did I just dream that up?

Charley
C R Huff

Having used the facet cube pumps for many years both on my Midget and my MGA I often get this loud ticking. I put it down to a bit of vapourising as it generally happens when I have been going like joe f for a while and have built up a bit of heat under the bonnets. Other times it does it when I am just about to run out of fuel. Then it is not vapourisation but cavitation!
Robert (Bob) Midget Turbo

A check valve that is stuck open will cause continual running, but not rapid running. Rapid running is caused by air in the line. Cheers - Dave
David DuBois

David,

Thanks for the clarification.

Charley
C R Huff

The problem I think that is being described is NOT fast ticking of an SU fuel pump but the LOUD ticking sometimes experienced when using the facet pump.
Robert (Bob) Midget Turbo

Are you using a pressure regulator between the pump and carbs?

PeterJMoore

This thread was discussed between 21/08/2010 and 25/08/2010

MG Midget and Sprite Technical index

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