'93 Polaris 500 EFI

Troubleshooting '93 Polaris 500 EFI. It has sat for two yrs, it ran great on it's last ride. It has fresh gas, new plugs(w/good spark) and a new battery. I have cleaned all the connections to the ACS and ground. Fuel system starts and runs for 5 seconds as it should. I have bench cleaned the injectors and there is pressure in the fuel rail. It does run when I put a bit of fuel in each cylinder, but only that fuel then dies. I have read the manual, and it says the ACS unit is good if the system pressures-up. Any suggestion would be well appreciated in case I'm missing something obvious! I have read many threads on the EFI but with no luck on fixing my issue. E-Roc

'93 Polaris 500 EFI