Volvo Repair: rotates but will not start, volvo 240 dl, volvo 240

Question
my friend has a volvo 240 dl jettronic, he replaced the cap rotor wires and plugs and coil. The vehilce will still not start, it turns over but will not start. We checked for spark by taking off a plug wire and putting a plug in the wire and setting the plug on the metal oil cap to see if it sparked, there was no spark. What else should we check or replace to make a spark? thanks

Answer
you need to check for a power signal to one side of the col and an oscillating signal when cranking the car over at the other side of the coil.if there is no power siganl check the fuses and connections at the battery.also check the wiring harness for signs of insulation coming off and wires shorting out.this was more common on earlier 240's  82-85.if it has power but no oscillating power it could be a control unit problem.