Fuel Return To Tank---or Not

[205007 12]

I bought a non runner and been fiddling today with a strange one- the car cranks but does not fire

 

 

Got spark seems good and strong

Got some fuel but suspect not enough pressure

 

changed tachy relay no change

plugs sooty but not wet

changed fuel regulator

 

hardwired the fuel pump and took the return pipe off at the tank end

 

if i run the pump continuously no fuel returns along the pipe (even after a couple of minutes!) to the tank

 

as soon as i disconnect the pump i can hear the fuel running back into the tank

and if i crack the fuel rail there is zero fuel in there

 

is there a one way valve somewhere i need to change??

 

As i said i think i know the answer

[blessed6383 0]

are the fuel lines the right way round? i made this mistake before

[205007 12]

top is out

bottom is in

 

i do get fuel out but no return

[large 33]

top is out

bottom is in

 

i do get fuel out but no return

 

Top of what?

The pipe to the top of the fuel rail is the pressure line.

The pipe from the fpr is the return to tank line.

 

The only other thing in the pressure line is the fuel filter, thats not blocked is it?

 

I seem to remember someone one here saying that there is a non return valve in the fuel pump but I am nowhere near 100% on this.

Edited August 29, 2010 by large

[205007 12]

sorry i meant

 

as you look at the pump the pipe on the top is out and the one below is the return

 

no the filter isnt blocked ive now found i have fuel to the rail (after 10 seconds of the pump running) and it comes out about at a good rate of knots when the fuel rail is undone

 

it must be the non return valve broken at the fuel goes back along the line when the pump is off

 

new pump methinks

[Mad Professor 7]

As you have fuel making it's way upto the fuel rail but not back out again, I would say you have a weak fuel pump, or bad power to the pump.

 

The fuel pressure will need to reach at least 3bar before any fuel is then returned to the tank.

 

Have you got a spare battery, if so make sure it's fully charged and try connecting it directly to the fuel pump.

 

If you still don't get any fuel from the return pipe, It would indeed be a iffy fuel pump.