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MG MGB Technical - Fuel Pump clicks continuously

I have a '78B with the original fuel pump. Most of the time when I turn on the ignition, the pump clicks away continously. Sometimes (20%)the clicking will slow down and stop like I believe it is supposed to. In all cases, the car starts and runs fine. There are no fuel leaks. Is there something wrong with the fuel pump, and if it has to be replaced what is recommended as a replacement?
Thomas

Thomas

Continuous clicking usually points to an air leak - tank side of pump. But if it stops periodically I wouldn't worry.

Dave
Dave Wellings

But leaving it is what leads to total failure miles from anywhere on a wet and dark night. Your car is talking to you - listen. Check that fuel is not pumping out of the float chamber overflows first, or confirm that you can stop the ticking by sealing off the open end of the pipe at the carbs. If not the pump non-return valves could be bad, but they rarely give problems. Could also be an air-leak on the suction side of the pump, which could be a peforated pipe inside the tank if it depends on how full the tank is. If replacing go for the original SU, and my advice would be to go for the original pointy type and not the pointless type - BT, DT, it's now at the back of the bench.
Paul Hunt

I second Paul - buy a new SU standard pump - it will pay you back with years of trouble free service.

The constant ticking without leaks points to a bad pump inlet valve (probably dirt trapped) - the fuel is leaking back to the tank.
Chris Betson

Thanks for all your help - I have no problem replacing the pump with an original SU, the cost is not that high. I am suspect of the reliability of banjo unions with the two seals, I would replace those with new ones also. Can you comment on any special hints to insure a reliable seal with these unions?
Thomas

I just got a new SU points-style pump -- it came
with two o-rings instead of fiber washers for
the banjo union to pump joint. I used two fiber
washers between the banjo bolt head and union.

I found a neat trick in the archives from Paul Kile --
wrap the fiber washers life-preserver style in
teflon tape to prevent leaks. So far the new
pump works great with no leaks.
Ronald

Had no problem when replacing either of my pumps. Mind you, USA fuel is said to be more aggresive than UK.
Paul Hunt

Wow - some people worry more than me!!!
OK Thomas - throw a replacement pump in the boot and worry about it if it NEVER stops ticking. As a last resort change it over if you get a spare hour, but life's too short .................
Dave

Dave Wellings

Thomas,
Your SU pump may just need adjustment, Try winding the diaphram spindle in a hole or two (clockwise), so that the points "just flip over".
Of course you could just bypass the loathsome thing with a nice cheap reliable Japanese one from a wrecker/breaker. I have a '82 subaru one that fits nicely in an out of the way corner in the engine compartment. A result of spending $60.00 on new SU points, much fiddly adjustment then finding out the amature was faulty (at night, in the rain, on the top of a very large, very busy, pedestrian hostile bridge)
Good luck with it.
Peter

It wouldn't hurt to perform exploratory surgery on the pump before declaring it dead.

By bet is on cracked in-out reed valves. I replaced mine two years ago after the pump began ticking
continuously and an inspection showed both to have hairline cracks.

The pump has been OK since.
Daniel Wong

Its already been said, but don't forget to check float overflow before touching the pump at all. It takes less than a minute and could save hours of barking up the wrong tree. Dean
Dean Lake

"Try winding the diaphram spindle in a hole or two (clockwise), so that the points "just flip over""

The correct setting is 'just flips over plus a further quarter turn (four holes)'. Without the 'plus' it is too marginal and may not flip over under some circumstances of temperature etc.
Paul Hunt

Why is it that a fuel pump with replacement points is never as good, or as long lasting as original??
Is that Murphy's law??
Dave Wellings

This thread was discussed between 02/10/2002 and 04/10/2002

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