I have researched the Rover Workshop manuals, and it is still unclear.
I think it is constantly open with engine temp above 70c and engine speed above idle.
I may have a contact that knows the chap involved with the software for the Rover MEMS, I'll see what i can find out if atall
Maybe some one could write up some code?
wouldnt be that difficult would it?
Extracts as follows
Purge valve
The purge valve is driven directly from by the ECM.
When the purge valve is opened it allows the EVAP
canister to vent into the engine inlet manifold. The
valve is opened by the ECM for varying periods
under specific engine conditions to avoid degrading
engine performance.
Evaporative emission canister
The evaporative emission (EVAP) canister is
situated beneath the LH inner wing valance, and
contains charcoal which absorbs and stores fuel
from the fuel tank when the engine is not running.
When the engine is running the vapour is purged
from the canister into the engine and burned.
The EVAP canister is purged when the EVAP
canister purge valve is opened. Manifold depression
draws fresh air into the canister through the
charcoal, which releases fuel vapour into the inlet
manifold.
Evaporative emission canister purge valve
The EVAP canister purge valve is operated by the
ECM. The valve remains closed until engine
temperature rises above 70°C. This is to maintain
engine tune and catalyst performance. If the valve
was to open with the engine cold or at idling speed,
the enriched mixture would delay catalyst light off
time and cause erratic idling. When the purge valve
opens, fuel vapour from the EVAP canister is drawn
along a pipe through the valve and into the inlet
manifold for combustion.
If I can get hold of a Can from a carb engine that uses a vacuum stat to operate a valve in the can, I think I'll use that
