S2 non start problem

[peanut]

My S2 has been playing up a bit when the engine is cold (for the first 2-3 minutes ) for a couple of months now.
It tends to surge and the low throttle position is hard to hold at slow speeds when the engine surges and then dies etc.

It has sat unused for a couple of weeks at a time

Also periodically the big red warning light has been coming on when driving. Not every time I go out just occasionally.

I just went to try start it after charging the battery.

The engine turns over really quickly but it won't catch at all.
I noticed the rev counter didn't jump though ??
There is a big fat spark at the plugs but I haven't checked the fuel pressure and delivery yet.
I am inclined to think water in the fuel filter or problem with the pump but what do you guys think ?
oh yes I replaced the DME []

 

[RC18B 911 turbo]

If it turns over really quickly the engine may have low compression for some reason but other than that I can't really offer any help due to not having a clue about mechanical things lol but I'm sure someone else will correct me soon enough.

 

[peanut]

there have been lots of threads like this on several forums. It would be really helpful to archive them somewhere to aid diagnosis. There is so many things it could be but I'm inclined to think its fuel related as I did get it going once by giving it loads of throttle and pumping it lots.