No fuel pressure...

[anonymous-user]

Just changed the fuel hose from the swirl pot to the fuel pump, whilst I was about it I changed the filter. I now can’t get fuel pressure up to the engine. I have gone back to the filter (checked it s the right way round) and tried to suck fuel through but it is a vacuum?

Is it all supposed to self prime? I am wondering whether I have disturbed a dying fuel pump?

Anyone help with any tests or have I missed something?

(If I have a naff pump does anyone know the part number)

Cheers

Doug

[blaineuk]

if you turn the ignition on and move the flap in the air box does the pump run.

[wedg1e]

If the pump's not running you may have a broken earth or feed to the pump.

[anonymous-user]

I rember that sametime back if you move the Flap the pump engages... I will try that then check the earth. Cheers.

I do get the feeling I disturbed something.

[leorest]

sidewinder said:

...vacuum...

A bit unlikely I know but, it hasn't somehow got connected the wrong way round has it? Either electrically or plumbing?

[GreenV8S]

Power the pump direct from the battery and see if you get pressure then. (How are you measuring pressure at the engine?)

[anonymous-user]

When I operate the flapper the solenoid clicks but the pumps not working, so I need to check the wiring. Also I will run it from a separate 12v supply to see if the pumps ok or not.

If I take the hose off from the "out" of the fuel filter no fuel comes out, if I then get a clear piece of pipe and suck from the filter I can’t draw any fuel through? If the pumps siezed I would still assume some fuel would come through?

I must have disturbed the pump, somewhere along the line, as I took it off to remove it form the old pipe easier.

Although I said I can’t get pressure, I haven’t measured it, I just checked for fuel at the engine by taking pipes off, there is some there but the spark plugs are bone dry.

[blaineuk]

had my filter off for a couple of weeks and no petrol came through the pump in that time, so must be the design, more like you have a bad connection

[GreenV8S]

If there's no noise from the pump then you almost certainly have an electrical problem.

[wedg1e]

sidewinder said:

If I take the hose off from the "out" of the fuel filter no fuel comes out, if I then get a clear piece of pipe and suck from the filter I can’t draw any fuel through? If the pumps siezed I would still assume some fuel would come through?

IIRC the fuel pump has a non-return valve on the outlet that keeps the rail pressurised. You probably can't suck hard enough to overcome the spring that's keeping the valve closed...

[anonymous-user]

Thanks for the replies. Have 12V supply at the pump. Now realise why the solenoid was so loud when moving the flap... when I connected an external 12v supply to the pump it’s seized just a dull thud... anyway pump knackered off to get a new one.

Cheers

Doug