Volvo: 1995 Volvo 850 turbo wont start, fuel pump relay, cam sensor

Question
My volvo is cranking but no spark.  It starts at first attempt but then immediately turns off and just keeps cranking after that.  Took to a mechanic ($220.00 for diagnostics) who replaced the ignition(saying the ignition was loose and needed to be replaced) and got it running.  He activated fuel pump wsith power directly to pump it and it started fine.  He says that the fuel pump relay or the fuel ignition relay needed to be replaced.  I have replaced the fuel filter, fuel pump relay (#103 in the relay box)and it is still not working and doing exactly the same thing it was doing when the problem began.  One other point he made was that the pump (prior to bypassing the relay) put out a voltage of 43 versus 5... Not sure what all that means???  Also, buzz sound from throttle area even after I've turned off the engine which he said happened to him and he said tapping fixed it.  
Can you please help.  I've already put $400.00 into this problem and now he says it may be a couple hundred again in diagnostics to fix the same thing that was only fixed for less than 48 hours.
Thank you.
Thank you.

Answer
Viki,
Well first take the car to a shop that knows the Volvo. There are limited but somewhat useable fault codes that can be used to help the tech.  I would say that there will be a code for either the cam sensor and or the crank position sensor. Both sensors have a lot to do with spark. Also if there turns out not to be any fault codes then you may have a bad coil. There are not any fault codes that post for a bad or weak coil. Are you certain that the fuel pump continues to run when the engine turns over? No gas most times also means no spark. The control unit will not let the coil spark if there is not any fuel.