TD4 engine problems

Hi, I am new to the forum. I have inherited a freelander TD4 but its not working that well. Does anyone have advice or had this problem?
2016 - my sister had the car for 5 years, driving as normal then total loss of power and fuel pouring out underneath engine. Car towed back. Web research pointing to HP pump had gone. Dismantled, pump sent off for re-conditioning. "2017 left for 6 months, pump re-installed, car finally started after some fiddling around and patience.
Car MOT'd. Starts fine, idles fine but problem starts when ran for 10-30 mins or engine loaded. If you drive really carefully and slowly (not over 2000 revs) the problem may not begin but if driven normally then it will begin- lumpy, jerky, a bit smelly, partial power loss, engine light comes on. Really odd and difficult to drive.
Strangely the car can be stopped, switched off and back on and then the light will go and the engine is fine again.
I gave it to a Landrover specialist who first diagnosed it as a fuel pressure issue but didn't have the right equipment to test the HP pump so sent it to a diesel specialist. They say the pump is ok, but it needs a set of injectors (£1200)
I cannot believe the injectors could be the problem but i am no expert. Does anyone have any ideas of the cause or a solution.
thanks for the help
Marc

Get @Diesel Do to look at it.

Marc You need to get a leak back test done on the injectors if they are suspect, I doubt all four will have gone out of spec at the same time, also the HPFP was the regulator O-rings changed at the same time of it being looked at ? if not then they could be the problem, so could the fuel filter and or fuel pump in the rear OS wheel arch that is presuming it is a late 53 -06 model if not the fuel pump will be under the bonnet so will the filter.

You really need to get the FL on an good reader T4 or Hawkeye to access the fault results and engine reading just changing parts willy nilly will be expensive,

thanks for the reply.
The garage have changed the LPFP fuel filter in the rear wheel arch. I don't know whether the HPFP has a filter too.
regards injectors - surely if they were all bad then the engine would not run at low revs very well either?
I think i need to give it to a freelander specialist for inspection.

The Mad Hat Man said:

Get @Diesel Do to look at it.

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I'm blurry miles away!

Diesel Do said:

I'm blurry miles away!

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So?

I'd start with the fault codes personally

The Mad Hat Man said:

So?

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It's a long way to push it

Diesel Do said:

It's a long way to push it

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Gotta be cheaper than £1200 for a set of unnecessary injectors?

Tbh going on the description it sounds like it can't produce enough fuel pressure when the demand is increased so I'd plug it in and be looking at anything that can affect the fuel pressure initially

Agreed, someone who knows their way around the diags would probably help.

Without that, before splashing out £1200 on injectors, Shirley its worth trying a replacement lift pump (if it was just the filter replaced last time) and run a couple of tanks of injector cleaner in the fuel.

It's very unlikely to be the injectors. Start with the basics like, is fuel getting to the high pressure fuel pump? All the pressures are available on live data with a suitable reader. Most garages should be able to read live data.
If low pressure is ok, then move on to the rail sensor. The rail sensor is known to crap out, along with it's harness.
Check for vacuum leaks on the small vac lines too. Once you have eliminated all other possibilities, move on to the expensive bits.

Thanks for all your replies. I have been away which is why I have not replied earlier. FL still the same but It must be something small. Its starts fine, drive fine until it finds a hill or sudden increase in acceleration/demand. Once the eml comes on, it runs rough. You can rev through it and after 3.5k it runs smooth again but on return to normal 2k or idle then it runs rough again. If I stop driving and keep the revs at 2k then it does sometimes produce white smoke.
Once I switch engine off and restart the eML light goes off and it ticks over normally again until I reach another hill etc.
I need to find a Freelander specialist (one in Norfolk) who has the test equipment so I can rule some stuff out. The rail sensor harness has been replaced already. Perhaps it could be a faulty maf? Or perhaps the reconditioned HPFP is not working/installed correctly or the regulator o rings? cheers for al the help

If you suspect the MAF then unplug it and if there is a change, you have found your problem>