Air.......

Reet, here goes.....Series 2a with 2 1/4 diesel

Probably asked before but....I seem to have air in the fuel system. The pipe from top of the fuel filter which goes to the injectors, when running, has no air bubbles. The minute I switch off, there is the odd bubble and then a flurry of them to the point that no fuel stays in that pipe. I replaced the lift pump, polished all copper sealing washers, changed the fuel filter, all new seals and replaced the pipe from the filter to the injection pump. I bleed the filter,using the top pipe and nip it up as I am pumping. I then undo the bleed screws on the main pump and once the fuel is streaming out, nip them up too. Start the engine,which takes a while (need to upgrade the glow plugs) and once started, apart from the smoke (I think the pump needs altering a bit) it runs well and the pipes are full of fuel. Knock it off and that top pipe empties of fuel. Is this normal? I've ordered a non return valve,which I will fit inline as close to the take as possible,which is something I have done with a Discovery in the past, hopefully this will help.

That top pipe I think you're refering to is the return from the injectors and if theres no fuel getting to the injectors then its bound to empty of fuel.
Sounds like you have it running though?
When you bleed it follow the path of the fuel start at the beginning and work your way through it.
Got a photo of the filter arrangement?

Agree sounds like the spill return pipe , on mine it would leak from there and cause air problems
It would run and deprive for a couple of miles then conk out and need bleeding agin
Better off with new soft copper washers which compress a bit whennipped up , I think I tried ally washers too but sorted it in end, bubbles after polishing washers shows that not worked
It could be drawing air in on the suction side , so need to check connections tight at the tank ,
Ensure pick up pipe not split above level in tank,
Lift pump connections tight
Lift pump has non return valves in it so not sure you need another one

Please excuse any wiring and state of the vehicle, it's pre me and I'm working my way through things. The pipe I refer to is the clear one on top of the filter. I ask because this is the first time I have ever had a vehicle with this sort of set up, even the tractors I worked on only had 2 pipes in the filter housing, the top, clear pipe being the one missing. Once running, this pipe is full of fuel and no air bubbles. Once turned off, it appears to empty. If this is normal, then I have nothing to worry about. The car takes about 10 seconds to start when cold, after using the glow plugs, which it takes the same length of time without using them (they are the inline type and appear to be original!!!).

My pics are bloody awful! I have pressure checked the feed pipe with the rubber insert and there are no air leaks at any point. If the system appears ok, I will renew the glow plugs for the later type and re-time the injector pump because of the smoke on tick over. Once all this is sorted, I'll start on the wiring.

I git rid of that pipe on mine and blanked off the filter, the pipe now tees into the spill return from the injection pump to return to the tank.

Rodeo Joe said:

I git rid of that pipe on mine and blanked off the filter, the pipe now tees into the spill return from the injection pump to return to the tank.

Click to expand...

Thanks for this. I was wondering if I could just blank it and change the way the pipe feeds back. I'll get onto it.

Rodeo Joe said:

I git rid of that pipe on mine and blanked off the filter, the pipe now tees into the spill return from the injection pump to return to the tank.

Click to expand...

Do you have a pic, please? I guess it will be an 8mm T?

Yes 8mm I'll try and get a photo tomorrow......just shut up shop to light the BBQ now.

Rodeo Joe said:

Yes 8mm I'll try and get a photo tomorrow......just shut up shop to light the BBQ now.

Click to expand...

Thanks for that. Enjoy the BBQ

Re the spill return pipe emptying when engine stopped
In the diagram it’s pumped to filter and then to injectors any excess diesel not needed then returns to the tank by gravity and pumped when running
On mine it has a long tube into the tank
So my thought on that
If you have a long thin tube full of fuel hold it vertical with the top nipped it will tend to stay in tube due to the vacuum if you take finger off it will run straight out
So I don’t think the tube should be empty unless there is a leak letting air in

You can test glow plugs with a test lamp between BATT + and the earth lead on plug 1 to see if it lights and then keep moving towards no 4 as on pic
I have upgraded after one of the old pig tail plus went , but they’re ok when working
Also a risk of them snapping when messing about
Is the glow light on

You can see mines got a 2.5n/a in it but the pipeworks the same for the filter, the bolts sre the blanked off ports till I get some plugs.
Cameras not great so a bit fuzzy.