Recently I inherited a non(ish) running 2006 TD4 Freelander(FL). The previous owners had skimped on maintenance and destroyed the turbo by neglecting to change the sludge they thought was oil. It should be noted this FL was a runner just prior to the turbo dying. I have a spare TD4 engine that was taken from a nicely running 2002 FL that had body damage. It is from this engine that I am borrowing parts to try and diagnose this. Having just changed the turbo I was expecting to fire her up but alas that wretched cow just won't get going.

The symptoms

• There are no engine management lights on the dash.
• The engine cranks but will not start.
• A mere whiff of easystart gets the engine going.
• Once running, at idle the engine sounds good (no misfires, lumps, hunting, etc).
• The FL will move but it is underpowered.
• Above 2K RPM the engine will start hunting, surging, and bucking really badly.
• When trying an injector leakoff test I can see there is plenty of fuel coming back through the injector leakoff pipe!? This is almost as if the HP pump is sending all the fuel back to the bi metalic valve and it is coming back through the leakoff return.

I have connected an icarsoft LR v3 (this product is very poor, don't buy it):

• When cranking the low pressure fuel sensor shows a pressure of ~350kPa
• When cranking the fuel rail pressure sensor (FRP) is ~25000kPa.
• When driving (after easy start start) the FRP shows ~50000kPa at 2K RPM.
• When driving (after easy start start) the FRP jumps between 50000 and ~80000kPa as the engine hunts and surges above 2K RPM.

What I have tried

• Changed fuel filter, oil filter.
• 4 new NGK glowplugs.

• Replaced camshaft sensor (CS).
• Checked continuity of CS wiring harness from the connector to the ECU.
• Bypassed the entire CS wiring loom from back of CS plug to back of ECU plug.
• Checked the ouput signal of the CS sensor with a DMM: The voltage increased as the engine was reved to 2k RPM (after starting with easy start)

• Replaced crankshaft sensor from a donor engine.

• Replaced fuel rail pressure sensor (FRP) from a donor engine.
• Checked continuity of FRP wiring harness from connector to ECU connector.
• Measured the FRP voltage with a DMM: 0.6V at idle, 1.6V while cranking.

• Replaced MAF sensor from a donor engine.

• Replaced HP pump solenoid with solenoid from donor engine.
• Replaced HP pump solenoid O ring and gasket with new ones.
• Checked wiring to HP pump with oscilloscope: once engine is running (with easystart) there is a PWM pulse going to the solenoid.

• Replaced injectors with a full set from donor engine.

• When the cam cover was off the engine, the timing was checked using the procedure from the RAVE manual.

I am now all out of ideas. It would seem to me to be a fuelling issue but I am at a complete loss as to what the issue is. Thus I have no choice but to ask and hopefully summon the legendary @Nodge68 to give some kind of pointer where to go from here.

*optimistic bump*

Glow plugs, and/or a compression test required

I must have missed in the original post, it has a full set of new NGK glowplugs.

Compression test..

Or a snort of ether

If there was an issue with compression wouldn't it run like crap at idle?

Are you saying too much leak back fuel?
Maybe check with scope crank and cam sensor signals. Are the glow plugs getting power?
As you've used the oscilloscope to check fuel pump you could do simple compression test by measuring voltage at battery when cranking, all peaks or drops should be similar.

For any poor chumps that are reading this in 2025 wondering what the issue was...

The crank sensor.