MadaboutKitcars

Hi folks,
Havn,t posted much lately, but still around monitoring all the posts with interest.
Went out today for a couple of hours, just as Goo did, to enjoy this beautiful weather and noticed something which might be odd as I don,t know much about the low pressure fuel pump that pumps fuel from the tank to the front.
I have removed all the old trim behind the seats so that I can fit some new trim. Obviously the inside boot area is now open and on the floor is mounted the facet pump ( mounted vertically ). After about 1 1/2 hours driving I came into a small town and had to stop at some lights and noticed that I could hear the pump making strange noises when the engine was at tick over.
Do they make these noises or are they supposed to run silent ?

I would have thought that the most sound you should get would be a hum or tick. The Facet pumps operate using a solenoid I believe - not a motor in the normal sense.

Robin

I've only carbs with a low pressure feed and a return. My pump runs continiously and 'ticks' abot 4 times a second, I can only hear it when I turn the ignition on, or are sitting stationary.

And yes its been glorious weather. I'm doing about 80 miles a day going to work

Thanks guys, curioser and curioser. The noise sounds like the tinkling of metal and it wasn,t a regular beat. So will have to start it up and listen again. Cannot say I noticed it when I started up yesterday though, but then my exhaust isn,t quiet.

pump noise

Why not put 12 volts directly to the pump to test it and hear its tick/hum without the car started,and remove the feed at the engine to see its pulsing of petrol?

Hi Dennis,
Firstly, Facet pumps should be mounted vertically so no problem there. My pump makes a sort of 'clacking' noise when I first turn the key before I start my engine. It quietens down once the swirl pot is full and you can't hear it once the engine is running partly because of the engine noise and partly because my pump is outside the boot area below the car.
Were you low on fuel? Perhaps the fuel sloshed forward and back as you pulled up at the lights and the pump got a few 'gulps' of air. My pump is loud if not pumping pure fuel.
I don't think you've got anything to worry about.
...peter

Hi Dennis
This strikes a chord with mine, but I guess for different reasons. I added a sump to my fuel tank ( it acts like the swirl pot and eliminates the low pressure feed pump), and then have just the high pressure pump feeding the injectors. My high pressure pump runs continuously and is SO noisey - I can hear it against the tickover engine noise! I will be sending it back to Sytec when I get round to it for them to check it is running as it should. I just cannot beleive it should be as noisey as it is.
It is mounted horizontally (as advised by Sytec for the High pressure pump) in the thick neoprene / rubber sleeve so it is not being amplified by the chassis.

Mike

I've only ever run my engine with a 'splash' of fuel in the tank. The only time the LP pump makes a noise is when the splash becomes no more than a drip and the pump is starting to run dry.

If your pump started to make a noise after a longish run I wonder if the pump is beginning to struggle to draw fuel from the tank. Is the original marlin 'one way' tank vent valve fitted allowing air to escape from the tank under pressure but not allowing air back in to replace the used fuel. If so this may result in a partial vacuum in the tank which the pump is fighting against and perhaps starting to run a bit dry.

A long shot but worth a thought.

All replies are very interesting but Nigel's post made me think a bit. Having looked I believe that my tank does not have a vent, unless its so well hidden, but the outgoing pipe at the top of the pump goes straight towards the engine compartment. However there is an earth wire going from the pump to a strange chrome plated what only can be described as a vent type dome that is mounted om the back panel just above the spare wheel. It is fixed through the body panel. underneath it is a hollow tube with a wire mesh.
So I am wondering if this is a vent for the tank but has not been connected.
Will have to look through some diaries to see you guys have one of these things

Hi Dennis, I think we need some pictures of your dome thingy, but if you look in the 'boot' you should see the large filler pipe and just in front of this will be the vent pipe.

In this picture below during my build, there is a bit of fabric coated fuel hose which was just temporary at the time to stop dirt getting in the tank. But that should be where your vent exists the tank.


Fuel hose by marlinpeter, on Flickr

Sorry for late reply but my house mods have taken precedent since April and the Marlin is in second place at the moment.
Having had a good look at it in the daylight now, the dome thingy is a red herring ( where did that term come from ? ). Still don,t know what it is and what it is supposed to do. Probably best to take a pic as Peter suggests.
However, I too have a pipe similar to your pic Peter, right by the main fuel intake pipe and it has what I assume is an inline filter, which has been mentioned in Nigel's post.
So I can rule out the breather pipe. However, will have to give it another long run to see if the sound is replicated.

Will let you know. Thanks guys.