Originally Posted by
Victorian
Thanks for the replies. The whole setup is on the engine side of the firewall. There's no transducer or sensor, just a t-piece right at the carburettor which feeds a Bourdon type gauge. The gauge behaves impeccably, rising when the boost pump is on to the correct value, etc. We also know that when the gauge indicates zero, the engine stops.
Speculating
1. gauge is slowly going to die?
2. pump worn, when is it lifetime due?
3. leaking fuel or sucking air?
Setup on the engine side of the firewall only means you have to mount an action cam to forward firewall for in flight inspection ...