Volvo Repair: 1984 volvo problems, volvo problems, volvo 240

Question
I have a 1984 Volvo 240 fuel injected, I am stummped with a problem. When starting the car, the engine will run smoothly for about 3 seconds and then just die. I have replaced the fuel relay, and I know I am getting plenty of fuel, I have also replaced the dist. cap rotor button, spark plugs and wires and I know I am getting good spark. The injectors are new so I know they should be working fine, but as I stated, the car will only run smooth for a few seconds and shut off. What other components could be causing this problem and how can I diagnose the problem? I have ruled out fuel, and spark. Any help is greatly apreciated.

Answer
there are realy many things that could cause this.many of the engine senors could cause this or possibly a short in the wiring harness.the sensors will need to be fault traced using a repair manual.I would also check the harness for wires losing insulation and wires shorting to eachother