Early Discovery - Fuel Relay Problem?

I have a 1990 discovery petrol (carb) manual.

When it has been left awhile it takes a long time to start (10 sec or
more) and I've come to the conclusion it's because the fuel pump is not
running when the ignition is turned on. It seems to need the engine
cranking (or the ignition switch turned to start). Once started no
problem whatsoever and no problem restarting.

I've proved this to myself by priming the fuel system - connecting 12v
to the fuel pump before starting having been left overnight - and it
then pretty much starts on the button.

I need to find the fuel pump relay I think to troubleshoot further - but
where is it??!!!

Better still, if anybody has had this problem and solved it...

Many thanks
--
Martin Beenham

"Martin Beenham" <[email protected]> wrote in message
news:[email protected]...
> I have a 1990 discovery petrol (carb) manual.
>
> When it has been left awhile it takes a long time to start (10 sec or
> more) and I've come to the conclusion it's because the fuel pump is not
> running when the ignition is turned on. It seems to need the engine
> cranking (or the ignition switch turned to start). Once started no
> problem whatsoever and no problem restarting.
>
> I've proved this to myself by priming the fuel system - connecting 12v
> to the fuel pump before starting having been left overnight - and it
> then pretty much starts on the button.
>
> I need to find the fuel pump relay I think to troubleshoot further - but
> where is it??!!!
>
> Better still, if anybody has had this problem and solved it...


It sounds more like a leak to me, either air getting into a line or fuel
getting out of the float chamber.
TonyB

On or around Sun, 12 Nov 2006 15:08:53 +0000, Martin Beenham
<[email protected]> enlightened us thusly:

>I have a 1990 discovery petrol (carb) manual.
>
>When it has been left awhile it takes a long time to start (10 sec or
>more) and I've come to the conclusion it's because the fuel pump is not
>running when the ignition is turned on. It seems to need the engine
>cranking (or the ignition switch turned to start). Once started no
>problem whatsoever and no problem restarting.

it's not supposed to - if it's an electric pump, it's got a safety circuit
which cuts the pump after about a second of no-engine-revs.

>I've proved this to myself by priming the fuel system - connecting 12v
>to the fuel pump before starting having been left overnight - and it
>then pretty much starts on the button.
>
>I need to find the fuel pump relay I think to troubleshoot further - but
>where is it??!!!

You also need to find out where the petrol's going from the carb float
bowls...

The pump on the EFI ones runs for about a second when you turn on and then
stops. dunno if carb ones do the same, but if it's got the same pump cutout
system then it might.

--
Austin Shackles. www.ddol-las.net my opinions are just that
"You praise the firm restraint with which they write -_
I'm with you there, of course: They use the snaffle and the bit
alright, but where's the bloody horse? - Roy Campbell (1902-1957)

In message <[email protected]>, Austin Shackles
<[email protected]> writes
>On or around Sun, 12 Nov 2006 15:08:53 +0000, Martin Beenham
><[email protected]> enlightened us thusly:
>
>>I have a 1990 discovery petrol (carb) manual.
>>
>>When it has been left awhile it takes a long time to start (10 sec or
>>more) and I've come to the conclusion it's because the fuel pump is not
>>running when the ignition is turned on. It seems to need the engine
>>cranking (or the ignition switch turned to start). Once started no
>>problem whatsoever and no problem restarting.
>
>it's not supposed to - if it's an electric pump, it's got a safety circuit
>which cuts the pump after about a second of no-engine-revs.
>

Aha - I didn't know that. However, if I briefly operate the starter but
leave the ignition on then the pump seems to run happily - which is my
strategy for starting without excessive cranking. Blip - wait a couple
of seconds - start!

>>I've proved this to myself by priming the fuel system - connecting 12v
>>to the fuel pump before starting having been left overnight - and it
>>then pretty much starts on the button.
>>
>>I need to find the fuel pump relay I think to troubleshoot further - but
>>where is it??!!!
>
>You also need to find out where the petrol's going from the carb float
>bowls...
>

Evaporation through the overflow pipes? When I switch off and the engine
is hot I can see petrol vapour shimmering out the overflows and the
*occasional* drop of fuel but this stops as the engine cools. I can't
think there is any other way for fuel to get out of the float bowls and
I wouldn't think much goes by this route but someone here might know
better if there is a cunning way for fuel to escape my SUs. I sort of
thought that gravity should keep it in situ. Maybe I need to take the
float bowl off to see just how much petrol is in there after it's been
standing overnight...

>The pump on the EFI ones runs for about a second when you turn on and then
>stops. dunno if carb ones do the same, but if it's got the same pump cutout
>system then it might.
>

Occasionally it will run when the ignition is turned on, but will keep
running! As I said, I can also get it to run by blipping the starter and
it will then keep running so it doesn't seem to work like the EFI (or
it's not working correctly).

It's all about as clear as mud at present but thanks a lot for the
suggestions - all food for thought.

Cheers
--
Martin Beenham

In message <[email protected]>, TonyB
<[email protected]> writes
>
>"Martin Beenham" <[email protected]> wrote in message
>news:[email protected]...
>> I have a 1990 discovery petrol (carb) manual.
>>
>> When it has been left awhile it takes a long time to start (10 sec or
>> more) and I've come to the conclusion it's because the fuel pump is not
>> running when the ignition is turned on. It seems to need the engine
>> cranking (or the ignition switch turned to start). Once started no
>> problem whatsoever and no problem restarting.
>>
>> I've proved this to myself by priming the fuel system - connecting 12v
>> to the fuel pump before starting having been left overnight - and it
>> then pretty much starts on the button.
>>
>> I need to find the fuel pump relay I think to troubleshoot further - but
>> where is it??!!!
>>
>> Better still, if anybody has had this problem and solved it...
>
>
>It sounds more like a leak to me, either air getting into a line or fuel
>getting out of the float chamber.
>TonyB
>
>
But how does fuel get out of the float chamber except when the engine is
running and it's sucked into the inlet manifold? I'm baffled...
--
Martin Beenham

Martin Beenham <[email protected]> uttered summat worrerz funny
about:
> Occasionally it will run when the ignition is turned on, but will keep
> running! As I said, I can also get it to run by blipping the starter
> and it will then keep running so it doesn't seem to work like the EFI
> (or it's not working correctly).
>
> It's all about as clear as mud at present but thanks a lot for the
> suggestions - all food for thought.
>
> Cheers

Had similar on a 1990 TD Rangie, the leak was on the fuel pick up, lift the
boot mat (undo the put on the tailgate and pull it all out)

Remove the inspection cover in the middle of the floor and take a look at
the mankey fuel pipes where they enter the tank.

You have a couple of options if it is this pipe... fix or replace. I prefer
the replace it's not mega bucks.

On my TD it used to allow the fuel to syphon back in to the tank due to a
perforated pipe... not big enough to leak but enough to allow air in.. once
the pipe had syphoned back in to the tank it took lots of cranking to start
the engine due to the lack of fuel.. it also ran like a sack of spuds until
the air had purged. Eventually the perforation became bigger and it would
stall at junctions due to the amount of air being sucked in at tickover
being greater than the amount of fuel. Once replaced it was like a new car.

Lee D

Martin Beenham wrote:
> I have a 1990 discovery petrol (carb) manual.
>
> When it has been left awhile it takes a long time to start (10 sec or
> more) and I've come to the conclusion it's because the fuel pump is not
> running when the ignition is turned on. It seems to need the engine
> cranking (or the ignition switch turned to start). Once started no
> problem whatsoever and no problem restarting.
>
> I've proved this to myself by priming the fuel system - connecting 12v
> to the fuel pump before starting having been left overnight - and it
> then pretty much starts on the button.
>
> I need to find the fuel pump relay I think to troubleshoot further - but
> where is it??!!!
>
> Better still, if anybody has had this problem and solved it...
>
> Many thanks
> --
> Martin Beenham

If you still need to know the whereabouts of teh fuel relay:
It is under the bonnet and on the firewall. Square shape.
Hope you have solved the problem, though