Hi there people, im looking for help

I have a 1998 Diahatsu sportrak 1.6elxi, its whole purpose is as an off road vehicle

6 weeks ago we came home from our day out playing in the mud, since that its been started and moved in and out the garden for various reasons until this week when she would start up but not continue to run she would simply just cut out

so still needing her moved i just moved it backwards and forward on the starter motor
however on Thursday this week she just splutters at me when i tried to start her and today she wont do anything just turn over, things you should know are there is no alternator belt on her at the moment, cable tie between the crank and viscus fan (long story), as mentioned internal fuel tank with generic fuel pump,

i assumed this was something electrical since she has an internal fuel tank with a brand new fuel pump and new pipe lines supplying fuel to the injection system how ever ive just checked for sparks and there aint any ive check all fueses nothing is blown

So Ive put new spark plugs in (it needed them anyway),
ive changed the ECU with a spare i had (it was off a carb f300 though),
ive swapped coils and nothing changed,ive unplugged the water temp sensor after reading that it can cause some running issues every now and then, i dont imagine its a ht lead issue so any ideas could this be an immobiliser issue even though it started up ok then cut out and now wont start at all seems unlickly to me but im no expert

is the key coded and if it is what is it coded to (ecu, immobiliser, ring around the ignition if it has one

Anybody any ideas