Very clicky fuel pump!

[Sidney'61]

Hi,
I recently changed the pump as the old one stopped working, the spare one I fitted seems to work fine however when left on without the engine running it never actually stops clicking... this would hint that it is not getting any fuel, however, the car runs perfectly fine with it like this.
I'm probably going to rebuild the pump completely tomorrow anyway but what is likely to be the problem?

Thanks

[PSL184]

what is likely to be the problem?

Paranoia

[d_harris]

A student with too much time on his hands??

On a serious note, how often are the clicks?

[David53]

Well, if it's clicking it's pumping so whereis the petrol going? Have you checked all over the carby, float chamber, fuel line etc for a leak?

[autolycus]

Well, if it's clicking it's pumping

Not if there's a split in the diaphragm, or the valves aren't working as they should. It may still work, but the maximum delivery rate will be reduced. It's also possible to have the pump so far out of adjustment that the points "trip" with far too little movement of the diaphragm - in other words the pump is delivering far less petrol per stroke than it should.

Kevin

[David53]

Aaah....yes. I guess I was assuming the new pump was "New" and therefore not likely to have a fault. Silly me

[Pikey]

When the engine is running and ticking over Id expect the pump to tick every couple of seconds or so, just to top up the float chamber, if its ticking more regularly than this then I would say the valves need cleaning or re-seating.

One check you could do, ignition on but engine off, so that the pump ticks. After the float chamber on the carb is filled the pump should completely stop. If it doesnt you've got a pressure leak somewhere which could be a leaky needle valve within the float chamber, a leaky valve within the pump or the braided hose from the pump to carb is perished.

I very recently had the braided hose perish and it leaked fuel everywhere, very nasty!

The valves are easy enough to get at in the pump. Unscrew the brass union (the one that the braided hose goes onto). Under this you'll find a brass valve carrier arrangement and enclosed within it is a brass flutter valve, theres another flutter valve which is loose under the carrier. The valves are probably worn or dirty. Clean them/replace them or just turn them over so the opposite side does the sealing instead, if you know what I mean.

Also might be worth checking the fuel filter within the pump, which is directly on the under side of the pump under a brass screw-on cap. That may be clogged and the pump just simply can lift enough fuel.

Hope this helps

Steve B

[Sidney'61]

Aaah....yes. I guess I was assuming the new pump was "New" and therefore not likely to have a fault. Silly me

I just put the 'new' pump together so it's likely to have every fault!

The braided fuel hose is brand new so hopefully that won't be the problem but I'll have a look.
I'll try and reset the contacts and see what happens...

[rayofleamington]

I was assuming the new pump was "New" and therefore not likely to have a fault. Silly me

Doh!
Personally I'd assume that an old pump is less likely to have a fault. ;-)

Anyway - we didn't yet hear at what rate the clicks come - if it's one every 7 - 15 seconds it's not worth worrying about.
The pump 'stopping' happens when the diaphragm is loaded and no fuel goes to the carb. However this relies on a non return valve and the diaphragm - if either of these have a slight leak it will discharge and continue to click. A very small leak in the NRV is not a big problem.

If however it's running 10 to the dozen you are likely to be pumping air...

[bmcecosse]

And if the stroke has been set too short - it will click like mad trying to pump. Probably even when the engine is not running.

[Sidney'61]

we didn't yet hear at what rate the clicks come - if it's one every 7 - 15 seconds it's not worth worrying about.
The pump 'stopping' happens when the diaphragm is loaded and no fuel goes to the carb. However this relies on a non return valve and the diaphragm - if either of these have a slight leak it will discharge and continue to click. A very small leak in the NRV is not a big problem.

If however it's running 10 to the dozen you are likely to be pumping air...

'Fraid it's ticking very fast all of the time as if it were not connected to anything, though the car is driving brilliantly with it and we got down to Hatfield yesterday without much of a problem. It seems to smell slightly stronger than usual as I think it is seeping slightly from the joint by the diaphragm.
I swapped the diaphragm over from another spare pump that I happened to have around and it did exactly the same thing...
Are they symptoms of anything obvious?

Roy, if the stroke is set to short how do you set it longer?

[Pikey]

From memory when I rebuilt mine, what I had to do was:

Screw the diaphram into the back of the points/rocker arrangment and at the same time operate/push the diaphram against the points in like an 'on/off' sort of pumping action, until the points just 'click over'. When the points have just 'clicked' over, you then screw up the the diaphram a further 6 holes, and thats it.

Perhaps roy can confirm or correct me, but Im sure its something like that anyway.

I would say you are either pumping air, but I would have thought the engine would be suffering from fuel starvation and running badly, and you say its running ok. So it must be some sort of pressure leakage and you say you can smell petrol, so you must have a fuel leak, but I think you know that. I'd buy a rebuild kit £25 I think, (cheaper than a new pump anyway) and refurb your pump and at the same time buy a new needle valve and gasket for your carburettor.

Just a thought, check your petrol pipe between the pump and tank, you may have a petrol leak somewhere along that line. Double check where the petrol pipe exits the tank, the pipe sometimes breaks off where it joins the tank. Ive had a pipe break off at that point.

regards

Steve

[alex_holden]

Screw the diaphram into the back of the points/rocker arrangment and at the same time operate/push the diaphram against the points in like an 'on/off' sort of pumping action, until the points just 'click over'. When the points have just 'clicked' over, you then screw up the the diaphram a further 6 holes, and thats it.

Close, you screw it in until it stops throwing over, then back it off slowly until it just starts to work, then back it off a further four holes. Remember to energise the solenoid while you tighten the body screws. (BTW I did offer to run a fuel pump workshop at the National but only Dave was interested... )

[8009STEVE]

(BTW I did offer to run a fuel pump workshop at the National but only Dave was interested... )

I thought you did a pump workshop in the boot of your car.

[alex_holden]

(BTW I did offer to run a fuel pump workshop at the National but only Dave was interested... )

I thought you did a pump workshop in the boot of your car.

Yes, I ran the workshop for Dave, then later on I rebuilt Ani's pump.

[ani]

[/quote]Yes, I ran the workshop for Dave, then later on I rebuilt Ani's pump. [/quote]

And very impressive too Would be great to have you as a next door neighbour

[bmcecosse]

The method is detailed in the manual; - it's years since I rebuilt a pump - but seem to remember an element of experimentation until I got it running nicely. Still runs nicely today!

[rayofleamington]

btw - if it's racing, then it's going to wear itself out quickly, even if it does keep working!

[Sidney'61]

Had a look today, I fitted the diaphragm from the pump that just gave up into the fast ticking pump and it now seems to be working perfectly
I'll have to try and get a new diaphragm at some point then so that I at least have a spare...

Thanks for the comments everybody.