9chesh · Mar 29, 2014

I have just replaced the fuel left pump, and bled the fuel system using the bleed nut on top of the fuel filter and the nut on top of the pump.

To bleed it, I used the lever on the lift pump, loosened the bleed valve until the bubbles stopped and only fuel was being pushed out.

I have done this time and time again, the engine runs fine for a while - then coughs splitters and cuts out.

I then return to the bleed valve an the system papers to be full of air once more.

What am I doing wrong?
Please help!!

Chris

timc1967 · Mar 29, 2014

How long does it run? Are you sure the lift-pump is good? You might be bringing enough fuel up by hand when priming the pump to let it run a short while.

Turboman · Mar 29, 2014

9chesh said:
I have just replaced the fuel left pump, and bled the fuel system using the bleed nut on top of the fuel filter and the nut on top of the pump.

To bleed it, I used the lever on the lift pump, loosened the bleed valve until the bubbles stopped and only fuel was being pushed out.

I have done this time and time again, the engine runs fine for a while - then coughs splitters and cuts out.

I then return to the bleed valve an the system papers to be full of air once more.

What am I doing wrong?
Please help!

Chris

What type of engine?

9chesh · Mar 29, 2014

Thanks for the replies.

It's an old 2.5 the original 1988 engine.

The new lift pump came with a spacer that the old one didn't have, and it did occur to me that this may affect the position of the internal lever against the cam, but it did seem to connect with a decent amount of resistance agains the lever....

It runs for about 5 mins if idling - but about 200 yards when driving, so it does seen that perhaps it is indeed using the fuel that I am priming into it.

Where is the air coming from? Surely if there are no leeks, air shouldn't be able to enter the system?

Incidentally - the Haines manual mentions that you should prime the lever until you meet firm resistance - I've never done this before so don't really know what to expect - should the lever go solid?

Thanks again

Chris

Turboman · Mar 29, 2014

9chesh said:
Thanks for the replies.

It's an old 2.5 the original 1988 engine.

The new lift pump came with a spacer that the old one didn't have, and it did occur to me that this may affect the position of the internal lever against the cam, but it did seem to connect with a decent amount of resistance agains the lever....

It runs for about 5 mins if idling - but about 200 yards when driving, so it does seen that perhaps it is indeed using the fuel that I am priming into it.

Where is the air coming from? Surely if there are no leeks, air shouldn't be able to enter the system?

Incidentally - the Haines manual mentions that you should prime the lever until you meet firm resistance - I've never done this before so don't really know what to expect - should the lever go solid?

Thanks again

Chris

It maybe you aren't getting all the air out, and it is drawing in air that is in the system already. Changing the lift pump will put a lot of air into the filter and ip head.
Put bucket under the filter, undo the banjo on top, make sure the lift pump isn't on the cam. Then using the lever, pump fuel through the filter, don't be shy, a couple of pints in the bucket is fine. When clean fuel free of bubbles is running, do up the banjo whilst the fuel is running. Tapping the filter, and giving it plenty of time, will help any air bubbles come out. Then repeat this process on the screws on the pump head.
If this doesn't work, then air is being drawn in, probably by the lift pump, or one of the pipe connections hasn't resealed after the pump change, you may need a new fuel pipe, old ones don't always reseal after being disturbed.

toms3 · Mar 29, 2014

I had same problem, I removed the spacer and run without then primed the new filter by pouring fresh diesel in and screwing it back on (the prime lever on the new lift pump did nothing!?) Fired it up and no problem since.

jacksta · Mar 29, 2014

Isn't the spacer for TDI? The lift pump's I have bought in the past had lots of extra bits as I believe the pump is the same from back when the 2 1/4 was introduced.
It has been a while since I last did one.
Hope this helps.

9chesh · Apr 2, 2014

All back together - thanks guys. It was definately the spacer causing the issue, runs like a dream again now.

What a great forum this is

9chesh

Active Member

timc1967

Active Member

Turboman

Mab An Gov

9chesh

Active Member

Turboman

Mab An Gov

toms3

Active Member

jacksta

New Member

9chesh

Active Member

Similar threads