I think we are closing in.
The fuel pump relay contains other functions then controlling the fuel
pump. It also has relays for cold start valve and for disabling kick
As I understand the circuitry, the cold start valve relay should both
have crank and low temperature signal present to energize. So, once the
engine is running, the crank is released, the cold start valve should
deenergize and the ECU sholud take over mixture control.
Apparently, the cold start valve relay is at least energized when the
engine is warm, which it shold not, partly because the engine is no
longer cold and definately because the engine is no longer cranked.
I don't believe in a fault in both inputs, so I conclude on the fuel
pump relay. There is no other ways, the cold start valve can be
For sure the engine can be run safely with the cold start valve
disconnected, until the problem is fixed, as long as it can be started
in cold weather.