Faulty fuel pump?

[Pantz83]

How much noise should I be expecting from my fuel pump? I believe it is a Hardi electronic pump and when I turn the ignition on I will occasionally get a faint click but that is it. I disconnected the line to the carb and turned the ignition on and no fuel was pumped out, just a small amount of bubbling for a moment.
I'm guessing I am going to have to bite the bullet and buy a new pump?
Itching to get things going so frustrating having to wait for things to arrive in the post. When I last had a moggy you could usually find a lot of parts on the shelf in many motorfactors.

[firedrake1942]

Go back to the SU mechanical pump - much cheaper, much less noisy, easier to get going by hitting it! Order from ESM and it will likely as not be with you next day. Everything else I have ordered from them has been.

[Budgie]

I had a Hardy pump fitted to my tourer when I bought her ten years ago and she would either tick / clunk once when I turned the ignition on or a few times but she always started and ran fine. I had to change the pump about two years ago because she failed so I bought a genuine S U pump and the same applies.

[oliver90owner]

Electrically operated pumps stop working for one of two basic reasons - electrical or mechanical.

Electrical could be: Motor or solenoid windings damaged. Insufficient voltage or current supply. The pressure switch is faulty.

Mechanical could be that the pumping head is blocked (preventing the diapragm moving) or there is pressure within the pump, but no outlet.

Spare parts, if available, are generally cheaper than a complete new pump. Seems like it would cost nothing to investigate, before buying a new pump.

[Pantz83]

Thanks for the info all. Are there any diagrams out there for the Hardy so I know what I am looking at when dismantling? (I shall do a quick google) does the fact that when I disconnect the carb line it doesn't pump fuel out when the ignition is on indicate there is a fault?

[Budgie]

Thanks for the info all. Are there any diagrams out there for the Hardy so I know what I am looking at when dismantling? (I shall do a quick google) does the fact that when I disconnect the carb line it doesn't pump fuel out when the ignition is on indicate there is a fault?

If it doesn't pump out fuel with the ignition on and the delivery line disconnected then yes there's a problem with the pump, assuming power is going to the pump itself. The Hardy pump does not have a filter outlet and the points I'm told are hard to find if they need replacing, of course I'll stand corrected on the latter. I took the good advice from the late , great Roy BMC when my Hardy pump started to play up and plumbed for a new genuine SU and yes I know they are costly at around £80 new but it's piece of mind in the long term.

[Trickydicky]

I too have a hardy fuel pump for around 4 years and so far have had no problems with it. Have you checked for any tank blockages first? Try disconnecting the fuel line to the tank and blow down it to check it's not blocked.

[oliver90owner]

Have you checked for any tank blockages first? 

TD,

Don't they just continue to 'click' continuously, if there is no supply to the pump, like the SU versions? Or do these Hardi pumps have vacuum shutdown as well a pressure limiting mechanism?

RAB

[Trickydicky]

Have you checked for any tank blockages first?

TD,

Don't they just continue to 'click' continuously, if there is no supply to the pump, like the SU versions? Or do these Hardi pumps have vacuum shutdown as well a pressure limiting mechanism?

RAB

I should imagine that if the tank is blocked as the pump is sucking it will increase the back pressure and act as a valve, shutting off the pump. If I were the OP I would be completely disconnecting the pump and using a couple of short pieces of flexible petrol pipe and a couple of jars and see if the pump pumps fuel from one to the other just as a simple test to prove the pump.
As I said earlier I personally have found the pumps to be completely reliable.

[oliver90owner]

as the pump is sucking it will increase the back pressure and act as a valve, shutting off the pump. 

Doesn't the pump have to pump ('suck') continuously to prime itself were the tank to become empty at some point? Not good, if it shut down under negative pressure on the suction side?

I have found SU electric pumps to be very reliable. Only ever needed to clean the points or free off long-unused pumps in the past. No experience with Hardi pumps, but as a relatively new type for this application I would expect them to be more troublesome (in the longer term) than the OE item.

The SU pump would not give up, if there were no fuel delivery to it - it would just tick away trying to do its job and only stop ticking when the outlet pressure became adequate.

RAB

[Pantz83]

Just thought I should update you since everyone has been helpful.
I dismantled the fuel pump but couldn't see anything obvious but the thin rubber seal seemed to be stretched and would not go back together.
I'd already order a replacement used SU pump from eBay which arrived today.
I fitted it, ignition on and it pumped straight away... Still wouldn't start... dismantled the float chamber which was filled with what I presume was old fuel (car was last registered on the road in '92, so who knows how old!), so I removed that, reassembled and hey presto it starts first time.
Only problem now is the 'new' pump is leaking from one of the gaskets so I am going to have to return it to seller for repair which is typical for me!
Thanks again for everyone help and willing advice!