Volvo Repair: Hard to start 240 DL 1991, coolant temp, fuel regulator

Question
I am a mechanic technician, but this fualt has eaten my brain. I have a 1991 240 DL w/ 4 cyl. The fault that it has is that it is soaking the spark plugs with gas, in a way that when the fuel pump disconnected and spark plugs are removed and engine cranked alot of gas droplets are expulsed through the spark plug orifice and when spark are replaced the engine will start, but if pump is reconnected the engine will turn off. I replaced the ECM, fuel regulator, and all filters.
Have consulted other Volvo tech and have got to the problem, need help desperately  

Answer
Juan, the only thing you didnt replace was the coolant temp sensor.  Did you check the fuel pump check valve to see if its failed?  What kind of ECM did you put in the car?  Is the fuel regulator a Bosch regulator?  If you put anything in there other than bosch, you are asking for trouble.  Obviously the car is overfueling.  Roger