Jcb 3cx fuel lift pump problem

[Alister Hossack]

Hi guys I have decided to change my lift pump, and since doing so it just will not lift any fuel from the tank,it seems as if it's blowing air back into it,I can hear a bubbling noice every time I use the lift pump.
I have used a airline to clear any blockages,it's just bloody strange,I changed the lift pump because the last time I changed the filter it was taking ages to fill the filter bowl,and the engine was starting to run iratically when under load, like it was lacking fuel,so I thought it was either the fuel pump or the lift,so trying the cheapest option 1st.
So any help from someone else who has had a similar problem would be great.
Thanks

[Muz]

Hi guys I have decided to change my lift pump, and since doing so it just will not lift any fuel from the tank,it seems as if it's blowing air back into it,I can hear a bubbling noice every time I use the lift pump.
I have used a airline to clear any blockages,it's just bloody strange,I changed the lift pump because the last time I changed the filter it was taking ages to fill the filter bowl,and the engine was starting to run iratically when under load, like it was lacking fuel,so I thought it was either the fuel pump or the lift,so trying the cheapest option 1st.
So any help from someone else who has had a similar problem would be great.
Thanks

Is it an electric one ?

[Alister Hossack]

Hi no it's a hand pump, it's next to the turbo on the right hand side. I'm kind of thinking the trouble is with the water separator,which is on the left hand side on the bulkhead. The system is drawing air somewhere. I took the separator off and fitted a new seal,and when it was off blew the pipes going to the tank and lift pump,they appear to be clear. Got my son to check for suction while I used the lift pump, and there was so God knows, I'm wondering if there is a rubber o ring on the pipe leading from the tank, as when it's tight on the separator 15mm nut if I remember, I can still turn the pipe when it's fully tightened that can't be right, could be losing suction there.
Any ideas because I'm running out,may try and get a portable suction pump to try and draw fuel from the tank, up to the separator to rule out the feet pipe👍
Cheers al

[Gecko]

I'm kind of thinking the trouble is with the water separator,which is on the left hand side on the bulkhead. The system is drawing air somewhere.
Cheers al

I've just bled my 3cx following a filter change and sedimentor clean.
I was surprised to find the lift pump sucks from the tank, through the sedementor before it gets to the lift pump.
Any leak at the sedementor will allow fuel to drain back to the tank between pumps.
To aid the process, I loosened the outlet of the lift pump until fuel started to flow.

I can still turn the pipe when it's fully tightened that can't be right

That sounds like a stripped thread.