So if I leave the car for more than a day it won’t start, I stick jump leads on ( after exhausting battery ) and sometimes it will fire up first turn, sometimes after numerous attempts.
It’s as though it’s flooded when it does eventually start ( smell of fuel ) , once running for a few seconds it will restart no problem, I know I’ve got a dodgy O2 sensor, but can’t get under at the mo, as I’ve broken some ribs,, would the sensor cause it to over fuel on start up ?..
Otherwise it runs fine..

It wouldn't cause it to over fuel on start as it will be running open loop, but it may have caused the trims to set themselves way out. Do an adaptive reset and see if that cures it.

Coolant temp sensor can stop a Thor starting - mine was intermittently shorting out reading far too hot (140 odd c), and wouldn't start. If its gone the opposite way, it could possibly be overfuelling and messing with timing so much it won't start in this ambient temperature.

Just a thought - do you have a nanocom or OBD2 device to check engine data?

I’ve got a nano, I’ll plug it in again, I had fuel purge valve fault, I changed that, cleared the fault, but it comes back now and then,, I’m wondering if I’ve got a loom problem, my lpg refuses to work more than 5 seconds, I’ve changed everything on it , ecu, injectors, pressure sensor, solenoids, maybe there’s a wire out somewhere

Done adaptive reset, but will do again

When using just the vehicle battery does it turn over at normal speed or slow?
If you use jumps leads on the first attempt at starting will it fire straight up?
Run ok on petrol once started?
Among faults that will make the LPG ECU refuse to work on gas are main feed voltage issues, if it doesn't see a petrol injection pulse for one or more cylinders, any LPG sensor electrical issue or reading out of range issues.

Brand new battery, cranks fine,, as for lpg, I give up, been a year now without it, the prick round here who is the so called lpg specialist won’t touch it because I’ve re run and replaced the hoses ( he suggested it ) , I think he just doesn’t know what he’s doing, told me that unless the joint in the pipe was central that one bank would get a higher pressure, and the car wouldn’t run, lol

Hehe sounds like old skool advice that's since been seen to be wrong.. On a pressurised system such as your sequential system it's not important to have equal main feed pipe lengths. If it were important we'd see little difference between fuelling to different banks anyway at low loads but would see a difference in fuel trims at higher loads (when the pipes have to flow more so restrictions leading to drop of pressure at the end of the pipe becoming more apparent) with the bank fed by longest pipe having more positive fuel trims, not seen on anything except maybe extremely powerful engines with exaggerated differences in feed pipe lengths. An electronics analogy would be like having 2 lengths of 3amp cable, one length 10cm long the other length 5 metres long, stick a 12v LED light at the end of each length with the other end connected to a car battery and there'll still be 12v at the LED end but stick a 90watt halogen bulb at the end of each length and there'll be a lot more voltage drop at the end of the 5 metre length, but if we changed the cable to 60amp rated cable there'd be little difference in voltage at the bulb ends of either length, the 12mm internal gas pipe is more 60amp than 3amp lol.
Same with pipe lengths between injectors and manifold, if you have a 3mm nozzle in the injector then different lengths of 6mm internal pipe aren't going to cause different flow of fuel to each cylinder (and this can be proven by switching individual cylinders back to petrol). Still don't want too long pipes between injectors and manifold but that's because it effects the pulse of gas to the port rather than overall amount of gas to the port so instead of a quick pulse flowing X amount of gas at the correct time there can be a longer pulse still flowing same total X amount of gas so less of a pulse more of a continuous steady flow. Not much problem with more continuous steady flow instead of quick pulses during cruise conditions but can be detrimental to accuracy of fuelling during changing throttle/rpm conditions, throttle response and smooth idle.

Sounds somewhat like the fuel purge error might be the cause to me of the starting problems - If it refers to the Evap system then is it possible your getting far too much vapour flooding the manifold when its left (far as i know it should be closed in that state and only allow purging when its running, but maybe its not doing that correctly?).

Would suggest easiest way to rule that out would be to find the vacuum line that runs to the manifold and disconnect it, plug the end of it and see if that allows it to start any better the following day (Plug both the hole that it connects to somehow and the free end of the pipe).

LPG wise it would probably help to know what the LPG ecu is actually doing or complaining about as a starting point, any idea which system it is?

It’s a landi Reno’s system, it says pressure sensor faulty, ive changed it twice ( both Bosch ) , i then bought a complete system 2nd hand and swapped everything over, still no joy, it happened after my mate borrowed the car, at the time the temp sender had broke, so wires were joined, he switched it on to early in the cold weather and it blew the pipe off the filter, not ran since

Simon, I totally understand what your saying, I tried to explain the same thing to him, being a plumber for many years I understand how things like this work, it’s the programming side that throws me, lol

Given what you've said above about it blowing the pipe off the filter, It does sound like a wires come disconnected. When you say you swapped everything is that including the loom, or just the modular bits? Also is the lpg still trying to switch over? If so, it could equally be the lpg side flooding manifold with gas (either by a stuck or leaking injector, or the vacuum connection to the vapouriser, if it is that, then pulling the lpg fuse should help to stop it happening, or switching it back to petrol only).

When you say it stinks of fuel on startup does it seem to be petrol or gas?

Couldn’t swap the loom as mine is soldered, about the only part of the install that was good, I’m going to test each cable now, starting at pressure sensor ( fault according to scan ), starting up now sorted, one of the wires on bank b lambda was shite, pushed it home tight and seems ok now ( fingers crossed )