Odd SR scenario....

[Koshin]

I have an SR black top with what I think is an redtop harness. The car has some sort of tuned ecu. I tried to contact the company but they seem to not have the tune onfile so I dont know what the tune is. The car runs fine but had a Q45 maf on it and it was breaking up under full throttle. So I switched it to a stock SR maf. It was better but still is breaking up under full throttle. I went to swap ecu's out and found that the ecu is a 62 not an e5. So I put in a stock 62 ecu and the car would not fire!! This ecu ran one of my other cars so I know it is functional. I am trying to decide what route to take to diagnose the problem. I am wondering if the car would fire with a stcok E5 ecu?? I want to turn the car back stock and start over with it. Bought it from someone else. What would you guys do next?? IT sucks I dont just have a stock E5 laying around to see, lol...Thanks ahead of time