Some of these are general things, so wouldn't change overnight…. Copied from a post I did on 'another forum'.
It could be a number of things....
Is there any smoke???
Check all the intercooler hoses:
Delaminating hoses could be one problem, but also check for splits etc.
Is the turbo 'boosting' or not???
Fuelling:
Unscrew the fuel filter and see if it is filled to the brim (engine off)
If not, it is a sign that your lift pump is not pumping the required amount of fuel... i.e. that it's gone weak.
Injector pump:
You may have a split diagram in the top of the injector pump or it has been set to the wrong position
To check this, (with engine off) remove the four screws from the anode on the top of the injector pump
Mark the position of the diagram with a marker pen so that you can put it back in the same place, and then remove it by gently pulling upwards and check for splits.
If it is ok, then.... it may be at its minimum setting.
The diaphragm and cone controls the ratio between boost pressure and associated fuel delivered. A small pin (which controls fuel) slides against the side of the cone. As the diaphragm is pushed down, the pin slides inwards against slope of the cone and so more fuel gets delivered.
As you look at the profile of the cone, it has different slopes depending on which angle faces the pin. So depending on its rotation, you can set which slope faces the pin, and so which ratio of fuel to boost pressure is delivered.
Its max setting is the one that would cause the pin to move the most. I.e. so that the largest is facing towards the front of the engine. It's up to whether to set it to max or not, but I put it somewhere close ish (say 45 degrees from max). If the diagram has been assembled correctly there will be a dimple of the metal plate that should face towards the rad on the max setting.
The other fault that can occur with the injector pump is the pin that gets moved when the diaphragm goes up and down can seize. If you 'can' remove the diaphragm then you can see the pin, and can try and move it with a screwdriver. Most of the time, if it is seized it can be moved with a few applications of WD40. But if not, you need to get the pump rebuilt or a replacement.
Boost Pipe:
Check the pipe that runs from the actuator on the turbo to the anode on the injector pump - it may be that this split or blocked (disconnect and blow through with an airline)
Boost pressure of the Turbo:
Connect a Boost Gauge and go for a drive - try and find a longish hill and attack it flat out in 4th (or 3rd) and see what the maximum pressure is. It should be 1 bar on 15 psi (just over a bar which is 14.7psi) - if lower then adjust to suit.
Engine Timing:
Does the engine struggle to start?? Or smoke when running.
When the cam belt was replaced they may have incorrectly set the engine timing.
To check....(engine off)
If you look on the front cover on the engine, you will see an inspection plate attached by three screws, remove this and you will see the pulley that drives the fuel injection pump.
If you look at this, you should see a timing hole. Turn the engine over with a bar (with a socket on the damper bolt) until this timing hole lines up with the timing hole in the timing cover behind the pulley (use of a torch helps) - when it does insert an 8mm or 10mm drill bit (plain end first) - if you gently try turning the engine over now, it should be locked.
Once this is locked, go underneath the Land Rover (with a torch) and look up through the hole in the flywheel housing at the flywheel. If the timing is correct you should see a cut out in the flywheel. If it not there, try just turning the engine slightly either way with the bar (still with fuel pump locked) and look to see if you can see it. If the timing is correct it will be there.
If not.... remove the drill bit from the fuel injector pump and get somebody to turn the engine over with the bar until you can see it, to see how far out/and what your looking for.
Intercooler:
Get it leak checked or do it your self.
Easiest way is to bung one end, and pressurise the other (ideally between 1.5bar and 2bar) and then submerge in a tank of water - then look for bubbles.
Inlet Manifold:
Make sure the gasket is ok and not leaking.
Fuel Lines:
Check all the fuel lines for split, cracks, kinks etc etc.
Especially those on the feed side. On a Disco/Range Rover clean the fuel sedimeter on the rear of the chassis.
Might also be worth removing the pick up pipe out of the tank and checking the gauze (if fitted) is clean and the end of the pipe (and the whole pipe for that matter) is free from damage - also check the return is not blocked or damaged.
Fuel Cap:
Remove this when the engine is running (or just after) do you get a hiss of air??? - if so, fuel tank vent or vented cap may be blocked.
Ian
