Ok. I got hold of a 2004 fiesta 1.4tdci . Non runner. Eac fail read on dash. I used a code reader. No codes shown or stored. Brimmed the tank and she started up straight away.i thought last owner had run out of diesel ?
I took the van for a mot and it passed but would not start after. Got it started on easy start then it ran fine for 5 miles. Then limp mode and eac fail. !!!!!!!
To cut a long story short I took it to m & c diesels at Colchester essex and they went through it and found injector no 4 resistor was at fault. Which is on Top of The injector Was over fueling and so ecu was shutting the engine down. You can't replace the resistor you need a new injector. So onto ebay .got second hand injector for £60 fitted it and van has been spot on since.
The injectors on this engine are Siemens and do not need coding.
Here's a good tip. If it will not start. Unplug one injector at a time and try to start . If one injector has gone down it will run on 3 . DO NOT UNPLUG WHILE RUNNING ENGINE. you can cause fluid lock. As they are either on our off . If you Unplug one that is on you will flood that bore. This can wreck the engine.
Lastly as you must know if you have been searching for the solution to this problem . Do not try a new pedal sensor or low pressure fuel rail or anything else first. Waste of time and money. Try this first. Also get a egr blanking plate off of eBay. £3.99 and fit. Man this makes a difference. Car/van will be much much more pokey and will run better.

hope this helps someone