Viale wont start

Hello,
i am not german so i will write in english tnx for understainding

I have bmw n52 2.5 r6 motor with 218ps

So i have vialle instalation of lpg in my car, i bought car with instalation already instaled
System does have around 150.000 km
So first time i have problem with LPG vialle was that motor didnt work well, ive had a 1 led bar of gas in my tank according to vialle leds indicators. When i shutt off the engine and start it back on fuel it work normal. BMW error code was in 5. and 6. cylinder i cleared it and everything was ok on fuel but not on gas. Than gas didnt work anymore. I was thinking what if there is no good presure and that led bars was incorect of showing gas level in tank, so i went to gas station wich i use always the same and i filled it up with gas, and LPG work again with no problem, so there lpg vialle is not so accurate as it shuld be, becouse if there is not enaugh gas in tank system automaticaly shut it off and car works on fuel but this time it didnt switched as it shuould.


then i search for vialle mechanics and found one, he connects viale on viale software and we saw that 5 and 6 lpg nozzle does not have pressure as others do, and that the fuel pump doesnt meet 2500rpm as it should but only 500rpm. Mechanich listen to the pump and said that on hearing it works normaly So i used system normaly without a problem for around 20.000km, system works but it has problems with starting (from begining of my ownership) when you shut off engine working on gas, if you switch manualy from gas to fuel for around 7km before shutting off the engine than there is no problem, i was told and ive read on forums that vialle gas nozle leaks and when you shut off gas the nozles still leaks some gas in air manifold in the engine and thats why engine dont normaly start on gas again). Ok i understaind new nozles but system lpg is not on warranty anymore so this is around 1000 eur just for nozles.

I drowe normaly for arround 20000km and now i noticed that if i dont use LPG, but fuel so vialle is off, that the led control for switching vialle on, is off, no light no nothing,switch dont work, some other time ive noticed this in the middle of driving on fuel, somethimes at starts. I was thinking that vialle switcher have short on electrical harnes but i think is somekind of safty vialle issiue.
So my question is are gas pumps repairable or just need to bought new one couse in ebay newone cost 600eur wuthout gas nozle, but gass nozle i think is not so important at th etime as the pump is wich dont meet 2500rpm as mechanics said it should and i think this last problem is related to pump.

But i must say that if i manualy somethimes switch gas on every think works fine, problems are only with auto switching between fuel and gas and now this with switch lights on and off

So first i need to repair pump, so is it repairable or not? I cant determine wich pump i have couse on the pump is only serial number no model or so.

 

i got that kind of tank and pump



and that kind of switch