Fuel Pump Failure - do I need a pre-filter or a flush?

[Sardonicus]

Moisture in the fuel was the kiss of death for that pump petroleum wont mix with water as you know and petrol/oil will always rise above water/moisture and separate , I would say the car as spent long periods of no use or little use giving the moisture time to do its stuff especially being the lowest part of your fuel system

[Wicker Man]

Sardonicus said:

Moisture in the fuel was the kiss of death for that pump,… I would say the car has spent long periods of no use or little use giving the moisture time to do its stuff

Sadly, you're spot on about ‘little or no use’; It’s been languishing in the garage for the last 10 years!

But I now have some free time and some actual fuel pressure. Strangely, the note that came with the first replacement pump was exactly wrong. The large terminal is for the Positive supply:

[Wicker Man]

Hurrah, my TVR now starts and idles and drives! That’s three things it didn’t do at all last year. It’s running rough, but at least it’s running
The fuel pressure was a whopping 49 psi, so I’ve set that to 40psi, which is closer to the standard nominal 36psi. The AFR is all over the place, so lots more to do. Some fresh fuel might help. What’s the RON of ~ten year old petrol?

[Sardonicus]

Looks like an early Megasquirt install ideally Id drain that fuel rather than run it through the fuel system I certainly would not put the engine under much load if you dont drain it