limp mode for 2000km and solution!

A chirp from Africa! Thanks to this forum I have educated myself and finally solved some of the incredibly frustrating glitches found in the M47 bmw motor. I have a 2004 td4. I want to return the favour and share my experiences!
History; MIL flashed a few times.Because i had an extended warranty, i took to dealer(stealer) who diagnosed low pressure fuel pump. (extended warranties in South Africa are really not worth the paper they are written on miles of tiny print which exempt EVERYTHING) I paid my one third excess and departed.
on 250km drive home from dealer light flashed again. I changed fuel filter behind rh wheel arch and it seemed ok. How can a land rover dealership fit a new fuel pump but not fit a new filter?????????? Anywayzzz.Long story short, I found gravel and a pebble blocking the entrance to the filter. Between the sedimenter and the filter. Any competent mechanic would have checked and seen it whilst changing the pump. I Thought I had solved the problem. I then embarked on a journey towing a car on an A frame 2000 km north to Botswana. Occasional MIL light and surging which steadily got worse. On my way back, minus the towed car, it was much worse. (it seemed it ran better under extreme load??Weird) Finally engine light came on permanently and vehicle went into limp mode. 1500km to go to get home! Through much trial and error, I disconnected the turbo boost solenoid and the EGR and gained enough power to get back in limp mode at an average of 80km per hour. Then the fun started! With the help of this forum, I discovered a hole in the turbo boost solenoid and a totally choked EGR valve. Sorted and expected all would be ok. Zippo. Still in limp mode and zero power. Logic told me that there was no pressure in the common rail. Checked LP pump and filter and fuel was jetting out. interestingly, the new fuel pump was running continuously. When I opened a pipe before the HP pump fuel jetted out. I reasoned that the common rail sensor was telling the ecu that pressure was too high and so it was voiding it back to the tank. I started fiddling with the plug onto the common rail pressure sensor and immediately the MIL went off and the engine note changed. Took it for a test drive and it ran like a rocket! However it soon packed up again. Each time I fiddled with the plug it corrected itself. BUT... sometimes plenty of power and sometimes no power and black smoke. The big decision...Is it the sensor or plug/harness? Logic says sensor because fiddling with the plug did not always produce consistent power restoration but sometimes extreme black smoke. (MIL was off though.Weird hey??) Anywayzzz.. fitted new sensor and all is good again. Loads of pull and zero smoke. Hope this helps some poor sucker like me who bought the best 4x4 by far....
By the way..For South African Land rover owners, Jaco from LR part in south Africa ROCKS! This company seems to be able to get parts to you in a hurry.

Nice to hear a story with a happy ending

cool

yeah i was a bit lucky. I think folks need to know that one sensor malfunction can set off another. For example, a failing common rail sensor can also show that the low pressure pump has failed simply because it is running continuously. Computer iso sees it as a worn pump and springs that code. meanwhile it is the common rail sensor telling the computer that there is too much pressure so it must void fuel. Result is not ENOUGH fuel pressure for the injectors. This might also stuff up the the input readings on the MAF?? A thinking person needs to go over everything carefuly in sequence and not just replace the device where the fault appears. That device may be crying for help because another device has let it down!!

I have had a good look through this forum and am grateful for those that have been on before but I haven’t resolved my “limp mode” issues!
Engine warning light comes on, and on a long journey the engine has actually cut out, ( done it twice in last 2000 miles). I have cleaned the leads going into the ECU. There was a very small amount of oil, it is really clean now. I have changed the MAF sensor, I changed the crank sensor but the engine ran badly with the new sensor so changed it back to the original, and now runs fine, but still goes into limp mode, more recently as soon as after a few miles then gets worse on the motorway when at higher speeds leading to a shut down. When restarted engine warning light goes out and car runs ok for a bit then same thing happens. I have also tried to loosen the wastegate actuator which I could move with mole grips and have covered in lubricant, it is still stiff though.
Help, advice and suggestions welcomed. Not smoking and is pulling well before going into limp mode...

The place to start is with the diagnostic codes - it'll almost certainly give you an indication of what's wrong. Chances are its fuel pressure related which could be the lift pump, pressure regulator O rings in the HP pump or the connector on the harness connecting to the pressure sensor on the fuel rail.

Thanks, going into the diagnostics tomorrow so will keep you posted.

The TD4 doesn't actually have a limp mode. It's down on power because of a fault, not because the ECU is in limp mode.

OK the diagnostics (on my TD5) said fault code on cylinder 4 injector dwell time not reached, injector output malfunction, and crankshaft position sensor error. The garage suggested I ordered a new injector (or a new one for an exchanged one with Land Rover for about the same price as a refurbed one) and a new crank shaft sensor.
I have looked into to removal and replacement and with the right tools, doesn’t look too advanced.

-Comments on replacement parts?
-Remedies for those diagnosed faults?
-The complexity of fitting replacement welcomed? This will be the first time for me.
-Finally should i get aftermarket parts or genuine Land Rover?
-Been told aftermarket sensor is ok but not for the injector.

Thanks again, this is a brilliant way to learn, really appreciated