If only running on one I would guess that fuel is getting pumped from the tank, I take it yours is twin injectors per cylinder so I would expect some fuel to be getting through.
First thing I would do is check the big connector in the side of the ECU is seated correctley, then I would pop the rubber bung out of the ECU and check the EPROM is seated correctley.
Is was on a DSC Cadwell trackday where Dallas's 916 Strada went on to one pot and that was the EPROM working its way loose
A couple of simple checks that you can do yourself
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