John
That’s exactly how the Advanced EVAP worked on my 2002 +8. After enthusiastic overfilling by a petrol attendant in France and a morning of splutter and cut outs (plus me in panic mode) I managed to clear it but wanted to analyse how and when it worked.
The GEMS system supplied an Earth to the constantly (ignition on) fed purge valve, I lashed in an LED test lamp and can confirm it did not operate on cold start up and had nothing to do with enrichment as that was done by widening the injection pulse width as seen on an O’scope engine analyser.
The purge valve was energised when the coolant temperature reached 80-82 degrees AND the throttle signal was more than 15% above idle. I fed this data back to David Ashley-Poole who I knew well at that time and I believe he included it in his magnificent GEMS manual.
I learnt not to overfill the car as the carbon EVAP canister was in the rear alongside the fuel tank and very difficult to bypass the ECU and manually purge!
BR
Colin
