Has nothing to do with fuelling, but with it disconnected it doesn't know to retard ignition advance and it doesn't know to control the Åmål-valve properly if connected. I run my car like this for some time back in the KE-jet days, but the distributor has to be turned to retard the basic advance setting a little bit.
As said there's a huge risk of breaking something if one doesn't know what he's doing.