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

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

Reply to
TonyB

On or around Sun, 12 Nov 2006 15:08:53 +0000, Martin Beenham enlightened us thusly:

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.

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.

Reply to
Austin Shackles

In message , Austin Shackles writes

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!

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...

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

Reply to
Martin Beenham

In message , TonyB writes

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...

Reply to
Martin Beenham

Martin Beenham uttered summat worrerz funny about:

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

Reply to
Lee_D

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

Reply to
desavigny

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