Massey 6490 error code

[Nukemall]

As above error e9090 t1.14 t2.14. 2007 sisu engine. Has only developed with the colder weather. Takes some time to start, then if stopped and restarted it starts straight away and the codes are cleared. Electric fuel pump is running for a long time when i turn the ignition on.
From an internet search suggests it may be a bad injector, but would this not bring a rail pressure fault?

 

[spudman*2008]

Engine speed sensor

 

[daveydiesel1]

@dee

 

[Nukemall]

Thanks for the replies, turns out it was the battery isolator giving notice. It packed up completely on the next properly cold morning.