89 240 Fuel injector problem ( I think)

[Da11as]

Hello All

I have an 1989 Volvo 240 with (belive it or not) 76,001 miles. I bought the car from a charity and its been sitting since 2003. Both fuel pumps and filters were bad and have been replaced. We are now getting fuel to the fuel rail. But we can't get the the injectors to fire. When testing were only getting a positive signal to injector, I'm told from the mechanic. A local volvo parts yard mentioned checking ground to injectors. Not sure how to do this or explain it or check it. Any other ideas or thought appreciated