Volvo Repair: Volvo will not start, fuel pressure regulator, vacuum line

Question
1991 Volvo turbo wg. It will not combust. I checked and replaced spark plugs just in case. I have spark on all 4. It's getting fuel, plugs are getting wet. I checked time manually,(time belt 6 month old). The engine turns. Is there a sensor that my causing it not to combust? My wife just drove it home and next time it wouldn't start. I had no signs of problem. Just over night. I also sprayed starter fluid in a vacuum inlet and nothing, I'm stumped

Answer
  Marco, how have you verifed spark on all 4?

   What you probably have going on if spark IS good, is a flooding situation. Too much fuel. Take the fuel pump fuses out, pull the plugs and dry them. Reinsert, fuses still out, spin it and try the starting fluid. If she fires, you know you are flooding. Most common cause is fuel pressure regulator leaking into the vacuum hose and sucking raw fuel into the intake. Pull the vacuum line and see if it's wet inside. If yes, replace fuel pressure regulator. Let me know.

Mark