Hello, hope someone can help. My ultra reliable 2010 4.4 tdv8 Vogue failed on me a few weeks back. Driving as normal then suddenly the engine just shut down, display stating system failure. Pulled to the side of the road... engine turned over but refused to start. Plugged in my IID which showed "Fuel pressure to high" I tried a few times my times more..still refused to start. Waited for 60 mins..it started..ran but stalled with any application of the Throttle, this time showing fault "Fuel pressure to low" I've replaced the Fuel Filter, replaced the fuel rail pressure sensor plus replaced the connector with the loom repair kit which causes issues and triggers these fault codes...still won't start. I've added more fuel..just incase there's an issue with the sender, still won't start. I have fuel going to the injectors..all pumps seem ok, but still nothing. No fault codes showing now still won't start..any thoughts would be appreciated, car was running well prior with absolutely no signs of an issue.

Is the engine turning over?

Assuming the engine is turning over, have you bled the LP fuel side? if so, I'd try cracking off an injector pipe to allow the fuel rail to vent whilst cranking - not too much otherwise it will detect low pressure again.

Thank you both..yes engine turning as usual...I've gone through the bleed procedure as changing the fuel filter.

Do you have diagnostics that can read live values? if so, what are the LP & HP pressures whilst cranking?

Thank you Phoenix, l give this a go. Thinking possibly CPS or Fuel pressure regulator? As mentioned it's showing no codes, won't start with Easy Start. Dealer network here in Northern Ireland useless... independents stacked up with work for months... nightmare

If it won't attempt with easy start (not withstanding it's a long way for it to travel!) then it's more than a fuelling issue, are you sure you got the wiring correct on the pressure sensor repair harness?
If you're happy with easy start as a diagnostic aid, then try pulling a hose off the plenum chamber and give it a quick blast directly into there.

Thanks Phoenix, I've an OBD diagnostic...it's showing 0 at the fuel rail before and after the Loom and Sensor change. I know I need to check fuel pressure which Diagnostic tool do I need?

Hi Phoenix, definitely. Short wire (2) to position (2) of the connector to be removed.

I've never used Easy start before..the chap from the AA tried..I was less than convinced.

As mentioned.. absolutely nothing has changed since I did the loom repair, symptoms exactly the same...as fault codes, zero. Only fault codes occurred at the time of breakdown.

You need something that will read live values, even the most basic OBDII will give fuel pressures, maybe experiment a bit with the one you have? Be aware that most engine management systems won't log DTC's until the engine is running (other than crank/c am position sensor implausibility) so don't rely on fault codes, you need to go back a step to good old manual diagnostics
Is fuel getting to the injectors? either crack off an injector union or pull out the spill pipe
Are the injectors triggering? check voltage - DON'T unplug an injector whilst cranking! Piezo injectors are difficult to hear at cranking so check the voltage, around 130-160V is about right
Is the air being measured - correctly? any induction or charge air leaks
Is the timing correct? - does the engine spin over too quickly or slowly
Check live values, do they make sense when the engine is at a standstill and when cranking?
Also - have you got the correct fuel? check for water as well.

I suggest monitoring the CPS during attempted starting as a priority because it is so easy to do.

Thank you all for the help. Finally found "Pressure at Fuel rail" on my IID reader....it showed zero. Removed the HP pump and dropped it into a local Diesel specialist for testing...and it's completely disintegrated and not good news as he suggests that all the metal particles from the pump will have wrecked the injectors so likely not just as simple as a replacement pump... strange as it gave no signs of failure prior to this.

Sorry to bring up an old thread but I'm having the same issue, 0 at fuel rail.

did you have to time the new pump to the engine?

Many thanks