hi all first post going against my better judgment I bought a 2006 td4 freelander never been off road 92k on the clock after owning it for a few weeks I was starting to like the beast till my wife phoned to say it was hard to start then lots of blue white smoke belching out the thing misfiring like hell. its defo fuel smoke not oil I took the injectors out and got them tested one was found to be faulty he said its to do with the electric top part it was not supplying enough fuel at idle .so I got another second hand injector fitted it had two dead glow plugs as well 4 new ones fitted all back together started up really good no smoke happy days took it out on the road within 100 yards mega smoke defo fuel. with the car running I took off the fuel rail sensor the car still ran when I put it back on the engine note changes so I think this works it shows 5v on two pins. it had a new lpfp fitted not long ago this seems to be ok but I can hear it give like a little miss now and again not a smooth continues buzz what now im a bit stumped it still has a misfire at tick over. just like to add its had a full service oil fuel air filter and the vortex mod from bmw and iv deleted the EGR

When you say miss at idle, do you mean its hunting, ie revs going up and down.
If so clean the contacts on the high pressure sensor on the fuel rail. Ours done this the other weekend, started it one Saturday morning and it ran like a bag of sh!t, hunting like hell, and trying to put some revs on just caused loads of smoke.

This sensor will have a 5 volt feed to it, probably what you measured, but it will also have another contact whos voltage will vary with pressure / engine revs, this is the signal back to the ECU, and that needs to be spot on.

I can only think with ours that the poor connection was fooling the ECU into thinking the pressure was lower than it really was, causing it to open the injectors for longer to get the required amount of fuel in, obviously this was too much and the revs picked up, causing it to immediately cut the fuel to bring the revs back down, and so it went round, hunting like hell..
My theory anyway..

There is a known problem with water ingress on this connection, and a new harness is available I believe..

I agree with your theory its something stupid it starts no probs even with 2 dead glow plugs it started ok so compression must be ok the last time I seen smoke like this a boost hose blew off my bora tdi 150 sport I thought turbo had gone lol its getting good boost so ok I think a new rail harness is the next stop. now the bonnet release has snapped got it open 10 minute job after taking sump guard off to find you still cant see the thing 30min job grrrrr what next

Just give the connection a good clean before buying a new harness, unless it looks totally fooked .....

just had a look at the rail harness plug looks mint i gave it a clean anyway still the same ? with the ignition on there is a buzzing nose coming from the HP fuel pump on the engine its like a burst air line but no fuel leak is this normal

If the rear fuel pump doesn't sound that great I'd definately check around there, that its all piped correctly thru the filter, separator etc, change filter while your in there, and that there are no leaks or evidence of it pulling in air. Check the power to the pump, its switched by a relay that may be a little shaky.

Could also be the pick up in the tank, have seen them covered in snot like stuff before..
Just don't go diving in to changing high pressure pumps and expensive bits until your absolutely sure..

ok today I fitted a second hand injector the car started first time ok quit smooth idle no smoke but really strong smell of diesel fumes like no cat fitted then after five minutes or so at idle it started to run ruff and the smoke is back iv fitted the bmw vortex mod but could it be the breather unit itself not working and is there a way of testing it before I waste £45 on a new one to be honest I just want it going to trade the thing in

here is a update the thing is still the same iv changed the FRC harness crank case filter unit i took the car for diagnosis no faults he said going by the smoke its your turbo and i should clean intercooler so i did new turbo fitted next to no oil in the cooler still the same i started the car the other day no smoke no misfire sweet as a nut for 20 mins gave it a good rev grrrrr smoke now back with misfire . we towed it to a farm road and gave it a blast mega pure white smoke iv never seen anything like it i did a compression test cylinder 1/ 24.2 barr 2/25.2 3/ 25.4 4/24.7 barr test was on a cold engine what next ?

I had a similar problem it turned out to be collapsed diaframes in the fuel tank sender

I take it you have replaced the Turbo breather filter too? Looks like an old style inline fuel filter that sits with one end open to air behind the engine (near where the vortex unit is located)

I had similar experience - changed one injector and bingo ran like a dream for a few days, then the smoke came back worse than ever. Apparently if you replace one injector it can put strain on the remaining older ones and cause them to fail. In the end I had all 4 done and haven't looked back. My bank account was, however, drained of over £900