200f(s) engine fitted to 240 gl

Tps and ems??? Could you explain what you mean by this? Would ems mean emissions system?

ems engine managment sytem tps throttle position sensor I am thinking about gas conversion and the tps appears to send a signal either on or off,which means only a crude single point sytem can be fitted.

I thought the TPS was a potentiometer not just a cut-off at idling speed. When I posted a question a few months ago about how fuel injection worked, after much debate the experts seemed to be agreed that the TPS was exactly what its name implies - a device for telling the EMS the position of the throttle, that is, how fast you want to go.