I have the above mentioned car on gas, Impco gas system.
The car has been on gas for 10 years and ran well. I recenly stopped running on gas, it starts and presumably runs on petrol then cuts out after say ten seconds.There is a unit on the firewall which clicks and it shuts down. If you switch to gas at say 40ks per hour it runs quite well. So I have assumed there is a part /valve in the system which needs to be replaced. There is a small vacuum hose on the inlet side of the aluminium doughnut type thing on the inlet manifold,if you disconnect this when it starts on petrol it keeps running , if you reconnect it it stops.My thinking is it could be this valve. I would greatly appreciate any advice. I had it to a mechanic $500 later I am no better off, they just don't have a clue, they can't even deduce which is the faulty part.