Please help - 6 Cyl Series 3 Fuel Pump

Hi All,

Just serviced my newly aquired 1973 Carawagon, put a battery on her and
turned the key....

As soon as the ignition lights come on there is a loud clicking noise coming
from the fuel pump... this clicking is in fact so fast that it almost sounds
like a humming noise... and no fuel is getting to the carb. (She runs
lovely though when I temporarily made a different fuel source).

So can anyone shed some light on this strange noise for me ?

Mike.

On Thu, 13 Jul 2006 18:27:23 +0100, Mike wrote:

> Hi All,
>
> Just serviced my newly aquired 1973 Carawagon, put a battery on her and
> turned the key....
>
> As soon as the ignition lights come on there is a loud clicking noise
> coming from the fuel pump... this clicking is in fact so fast that it
> almost sounds like a humming noise... and no fuel is getting to the carb.
> (She runs lovely though when I temporarily made a different fuel source).
>
> So can anyone shed some light on this strange noise for me ?
>
> Mike.

Didn't some of the old fuel pumps work that way? Once they got up to
pressure the ticking slowed down and stopped. If thats the case it sounds
like the fuel pump isn't getting the line up to pressure for whatever
reason.

Eddie
--

If you don't know who's watching the watchmen.
The watchmen are raiding the warehouse!

On Thu, 13 Jul 2006 18:52:47 +0100, Corp-Rat <[email protected]>
wrote:

>
>Didn't some of the old fuel pumps work that way? Once they got up to
>pressure the ticking slowed down and stopped. If thats the case it sounds
>like the fuel pump isn't getting the line up to pressure for whatever
>reason.

I'm not familiar with a LR one (my series 2 and 3 were both driven off
the block) but on the mgb a rapid ticking meant a blockage on the fuel
feed to the pump, steady ticking means no fuel.

AJH

"AJH" <[email protected]> wrote in message
news:[email protected]...
> On Thu, 13 Jul 2006 18:52:47 +0100, Corp-Rat <[email protected]>
> wrote:
>
>>
>>Didn't some of the old fuel pumps work that way? Once they got up to
>>pressure the ticking slowed down and stopped. If thats the case it sounds
>>like the fuel pump isn't getting the line up to pressure for whatever
>>reason.
>
> I'm not familiar with a LR one (my series 2 and 3 were both driven off
> the block) but on the mgb a rapid ticking meant a blockage on the fuel
> feed to the pump, steady ticking means no fuel.
>
> AJH

Rotten pick up pipe.... try disconnecting it and blowing from the pump input
.... if you can blow bubbles in the tank then it's most likely fine.

If there is fuel at the input then there could be something wrong with the
pump it's self.

Is the filter super crudded up? would have to be real bad though.

Lee D

Mike wrote:
> Hi All,
>
> Just serviced my newly aquired 1973 Carawagon, put a battery on her and
> turned the key....
>
> As soon as the ignition lights come on there is a loud clicking noise coming
> from the fuel pump... this clicking is in fact so fast that it almost sounds
> like a humming noise... and no fuel is getting to the carb. (She runs
> lovely though when I temporarily made a different fuel source).
>
> So can anyone shed some light on this strange noise for me ?
>
> Mike.

Air leak at pump inlet - empty tank or leaking (broken) pipe from tank
to pump?

"Mike" <[email protected]> wrote in message
news:[email protected]...
> Hi All,
>
> Just serviced my newly aquired 1973 Carawagon, put a battery on her
and
> turned the key....
>
> As soon as the ignition lights come on there is a loud clicking
noise coming
> from the fuel pump... this clicking is in fact so fast that it
almost sounds
> like a humming noise... and no fuel is getting to the carb. (She
runs
> lovely though when I temporarily made a different fuel source).
>
> So can anyone shed some light on this strange noise for me ?
>
> Mike.
>
>

IIRC it is a standard SU fuel pump so you may have a stuck one way
valve (there are two in opposite senses) or maybe a punctured
diaphragm. All bits are still available from Burlen (
http://www.burlen.co.uk/index.htm ) who now make all the bits and also
refurbish SU pumps and carbs.

AWEM

On or around Thu, 13 Jul 2006 22:48:09 +0100, "Andrew Mawson"
<andrew@no_spam_please_mawson.org.uk> enlightened us thusly:
>>
rapid ticking is pumping air. normal sequence if the feed pipe from the
tank is empty goes a bit like this:

tickatickatickatickatickatickatickaticka
(pumping air/vapour and sucking fuel up line)

ticka tick atick atick atick atick atick atick atick atick
(pumping fuel to fill the float chamber)

atick atick.........atick...................atick.................
..................................atick

(float valve shut and line up to pressure)

>
>IIRC it is a standard SU fuel pump so you may have a stuck one way
>valve (there are two in opposite senses) or maybe a punctured
>diaphragm. All bits are still available from Burlen (
>http://www.burlen.co.uk/index.htm ) who now make all the bits and also
>refurbish SU pumps and carbs.
>
>AWEM
>
coo, that's handy.

--
Austin Shackles. www.ddol-las.net my opinions are just that
Blue: The sky is blue for a reason. Blue light is a source of strength
and harmony in the cosmos. Create a blue light in your life by
telephoning the police
from the Little Book of Complete B***ocks by Alistair Beaton.

In message <[email protected]>
"Mike" <[email protected]> wrote:

> Hi All,
>
> Just serviced my newly aquired 1973 Carawagon, put a battery on her and
> turned the key....
>
> As soon as the ignition lights come on there is a loud clicking noise coming
> from the fuel pump... this clicking is in fact so fast that it almost sounds
> like a humming noise... and no fuel is getting to the carb. (She runs
> lovely though when I temporarily made a different fuel source).
>
> So can anyone shed some light on this strange noise for me ?
>
> Mike.
>
>

That's the fuel pump telling you that tank is empty! It will always
click/buzz for a couple of seconds when the key is turned, but
should stop.

--
www.beamends-lrspares.co.uk [email protected]
RISC-OS - Where have all the good guys gone?
Lib Dems - Townies keeping comedy alive

beamendsltd <[email protected]> uttered summat worrerz funny
about:

> That's the fuel pump telling you that tank is empty! It will always
> click/buzz for a couple of seconds when the key is turned, but
> should stop.

Still got that pump on the shelf I bought probably 8 months ago.... do you
do the pipes that go into them, or at least some way to connect a fuel
line?... theres nowt only the thread showing.

Lee D

In message <[email protected]>
"Lee_D" <[email protected]> wrote:

> beamendsltd <[email protected]> uttered summat worrerz funny
> about:
>
> > That's the fuel pump telling you that tank is empty! It will always
> > click/buzz for a couple of seconds when the key is turned, but
> > should stop.
>
> Still got that pump on the shelf I bought probably 8 months ago.... do you
> do the pipes that go into them, or at least some way to connect a fuel
> line?... theres nowt only the thread showing.
>
> Lee D
>
>

Certainly do...

572535 Fuel Pipe Connector - External Fuel Pump (PRC3901) -
Defender 90/Range Rover Classic £6.46 inc VAT

Your diff bits are now on the shelf if you need them.

Richard
--
www.beamends-lrspares.co.uk [email protected]
RISC-OS - Where have all the good guys gone?
Lib Dems - Townies keeping comedy alive

Thanks everyone - I've got lots of things to try out then.... I'll report
back when I have a chance to look at it further.

Mike.


"beamendsltd" <[email protected]> wrote in message
news:f9b3464e%[email protected]...
> In message <[email protected]>
> "Lee_D" <[email protected]> wrote:
>
>> beamendsltd <[email protected]> uttered summat worrerz funny
>> about:
>>
>> > That's the fuel pump telling you that tank is empty! It will always
>> > click/buzz for a couple of seconds when the key is turned, but
>> > should stop.
>>
>> Still got that pump on the shelf I bought probably 8 months ago.... do
>> you
>> do the pipes that go into them, or at least some way to connect a fuel
>> line?... theres nowt only the thread showing.
>>
>> Lee D
>>
>>
>
> Certainly do...
>
> 572535 Fuel Pipe Connector - External Fuel Pump (PRC3901) -
> Defender 90/Range Rover Classic £6.46 inc VAT
>
> Your diff bits are now on the shelf if you need them.
>
> Richard
> --
> www.beamends-lrspares.co.uk [email protected]
> RISC-OS - Where have all the good guys gone?
> Lib Dems - Townies keeping comedy alive

Mike wrote:
> Hi All,
>
> Just serviced my newly aquired 1973 Carawagon, put a battery on her and
> turned the key....
>
> As soon as the ignition lights come on there is a loud clicking noise coming
> from the fuel pump... this clicking is in fact so fast that it almost sounds
> like a humming noise... and no fuel is getting to the carb. (She runs
> lovely though when I temporarily made a different fuel source).
>
> So can anyone shed some light on this strange noise for me ?
>
> Mike.

I think this pump is the same as that on the Rover 100 (basically the
same straight 6 engine), which I've had some experience of. The way it
works is that there is a diaphragm which is pulled in one direction by
a solenoid and returns with spring pressure. The solenoid is activated
by a contact which closes when the diaphragm has been returned by the
spring to its "rest" position.

The sequence is thus:
1) The solenoid operates and the diapragm pulls petrol in from the tank
to the pump chamber
2) The return spring returns the diaphragm and pushes the petrol from
the pump chamber up the feed to the carb
3) When the diaphragm returns all the way, the contact closes and the
cycle starts again.
4) When the carb float chamber is full, the backpressure in the feed
from the pump stops the spring returning the diaphragm to its rest
position, so the contacts then don't close until the carb float valve
allows more petrol in. When they do, its back to 1 again.

>From the above, you can see that the pump will operate continuously if
either there is no petrol coming up the feed to the pump or if there's
nothing to stop the petrol continuing to flow.

Unless you can see petrol emerging from where it shouldn't (leak) or
you have a **very** flooded engine (stuck float valve or sunk float in
the carb), then the problem is either an empty tank or a leak in the
feed line which is bleeding air into the line.

A common fault with this pump, btw, (although not the problem in this
case), is that either the contacts fuse or (more likely) the
suppression capacitor (aka condensor) across the contacts fails short
circuit. In either case, the pump will click once when the ignition is
turned on and then no more. If this is the case, try disconnecting the
capacitor - it's not a long term solution since the contacts will arc a
bit, but it will certainly get you home.

Further thoughts to my last..

Although I haven't met them, the following faults would also cause the
pump to operate continuously without any petrol arriving at the carb:

Feed pipe from tank to pump blocked
Inlet valve in pump stuck open or leaking
Inlet valve in pump stuck shut
Outlet valve in pump stuck open or leaking
Pump diaphragm perforated and leaking
Any other leak in the pump chamber

I suggest checking out all the possible causes outside the pump before
dismantling it or replacing it.

Regards,
Arthur C

ArthurC wrote:

> Further thoughts to my last..
>
> Although I haven't met them, the following faults would also cause the
> pump to operate continuously without any petrol arriving at the carb:
>
> Feed pipe from tank to pump blocked
> Inlet valve in pump stuck open or leaking
> Inlet valve in pump stuck shut
> Outlet valve in pump stuck open or leaking
> Pump diaphragm perforated and leaking
> Any other leak in the pump chamber
>
> I suggest checking out all the possible causes outside the pump before
> dismantling it or replacing it.
>
> Regards,
> Arthur C

Further suggestion - blocked screen on the pickup pipe in the tank. If the
pump is clicking continuously the problem is most likely (but this is not
certain) not in the pump - the common problems with this pump are
electrical not the actual pump, so since the electrical bit seems to be
working the first place to look is the plumbing to and from the pump.
JD