Yes I have driven it without the MAF connected and it's a different car , as it should be at low end and seems smoother as well , as soon as it's connected back up back to sqare one and flat as a pancake . It has a brand new genuine landrover MAF on ( the second one ) and is still the same as when I took it into the garage .
atvb Paul.
Paul,
Taking you back to this post above. Did you try this at high speed? At the end of the day the operation is simple. The more fuel you shovel in, the more power it develops. If the power is there without the MAF connected then the fuel system must be able to deliver the fuel. Pumps and filters are therefore out of the equation.
This means that something in the engine management system is telling the ECU to throttle back on the injection windows. What would do this? Well you've elliminated the MAF so its got to be some other sensor or its supporting components.
I own an L series so I'm not familiar with the TD4 lump but I do have the circuits for the engine management for both. A look through these for the TD4 and I can see several components that under certain failure modes will result in a loss of output.
On the turbo there is a boost control pressure sensor and a boost pressure sensor. If these are malfunctioning so to indicate to the ECU that the boost pressure is lower than it actually is then the ECU will reduce the fuel quantity as it doesn't think there is enough charge for the full works. If the sensors are reading a 'believable' value then the ECU may not raise a fault. It depends on how well the software is written. Obviously the trick is to get the garage to swap with a known good one. I don't see why you should have to buy that if the original is not faulty.
This next idea is a guess as I don't know the engine design but pressure sensors need a reference pressure. This is sometimes taken from the vacuum pump for the brake servo. Are these air lines (if at all present) split, blocked, collapsed etc. Worth a check.
There is a Camshaft pressure sensor. (What the hell does that do?) Does this engine have variable timing? I don't suspect so. This sensor must do something. Subsitute for a good one.
Finally, and this is a stupid but obvious one. Is the throttle position sensor working correctly and allowing the pedal to signal a high throttle demand? Put a brick under the throttle pedal and it doesn't go very fast.
A few thoughts to try and help you along.
Good luck,
Dave