I wasn't planning on dropping the tank. I can quite easily get to the fuel lines as shown in the last photo I posted. I can get an external pump very cheap and install it very simply. All I want to know is what size are the fuel lines as shown in my photo, and what sort of pump pressure would be suited. About 6psi?

I've said it before but... Puller pumps were around decades before electronics got safe enough to put a "spark" source inside a fuel tank, not that that's a lot of worry in a diesel tank and the puller pumps worked just fine because the fuel line was always solid from the tank to the pump. No silly quick disconnect fittings to leak fuel (yes I've seen them leak under pressure) out or air in.

Nothing wrong with an in tank fuel pump and DCJ probably should have done that in the first place. But an in tank fuel pump is not "required" to fix air in the fuel problems. Assuming no leaks a) at the filter head (requires a new filter head regardless of pump location) or b) between the filter head and CP3 (easy enough to fix) the cheapest fix is to drop the tank and invest ca. $10-15 in 4 hose clamps and enough marine grade diesel rated fuel line to replace the quick disconnect fittings.

Assuming you do the fitting replacement you can chose to or not to a) install an in tank lift pump (cost ca. $125) or b) and inline pump either back by the tank to in the engine bay (cost - Kennedy $195; Facet 40109 ca. $50 from Yacht Supply Depot, or probably a NAPA AFP E3309 ($84).

My personal experience was air in the fuel was caused by a burnt fuel heating element in my 1s gen fuel filter head and was cured by installing a 2n gen filter head. Quick disconnects remain in place and Facet 40109 + glass inline filter are still in a box on my shelf.

PS cannot tell you line size but if you can see it you can measure it. Just because you can see it does not mean these are the fuel supply line disconnects; as I understand it disconnects are on BOTH the supply and return lines and you can leave the return line disconnects in place. Consensus on psi seems to be 5-10 psi. CRITICAL if you do get a pump (in line or in tank) it must be a flow thru design (i.e. if auxiliary pump fails CP3 can still pull fuel thru it) other wise if that pump fails you are parked.

_________________
Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs

for a start, I think I'm gonna chop out the quick connects as shown in my photo. I measured it and seems to be 8mm id pipe I need. Also gonna replace the pipe from the filter head to injection pump. that appears to be 3/8" and obviously put new clamps on. I'll change that and use it for a while and see how it goes. For the past couple of days it's been good as gold...

_________________
'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go

Thanks for the input. For all the 10 minutes it'll take to cut the quick connects out and just put a straight piece of pipe in, I'll feel a lot happier.
As for the filter head, it doesn't look the best to be fair. Not sure where I'd get a new replacement here in the uk? Perhaps a good 2nd hand one would suffice?
How do you verify if it's it's good or not though..!

You'll need rubber tubing rated for Diesel fuel service - hose for water or gasoline is not suitable

A pre-owned item could be worse than the one on your KJ - the EURO filter head would be from an EURO dealer, or p'r'aps a new find on eBay - if you install an external electric lift pump, the priming plunger is not a need-to-have item when locating a replacement fuel filter head

You could also remove the primer and plug the hole for continued service from that head, after the lift pump install

_________________
'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go

Interesting. Didn't know that. Assumed I'd still need the plunger to bleed it after lift pump install. I can get diesel rated pipe easy enough and gonna use 304 s/stell clamps. May hold off on the lift pump idea for now. If the quick connects are out and new tubing in place and new tubing from head to pump is in, in theory surely it'll be fine! After all, that's how it came from the factory and it obviously works.