Tach not responding when cranking due to bad ignition coil?

So I have been having some problems getting my car to start. It had been sitting for a couple months and I noticed I wasn't getting any spark or response from the tach whatsoever when cranking the engine over. I was told that the most likely culprit was my CAS had gone bad seeing as that reads the revolutions and sends info to the computer and tach etc. From what I have read when this goes out it will either kill the ignition or the fuel or both. I am not sure how this part could go bad just sitting but I decided to buy one anyhow. I just picked one of these up fairly cheap and I am hoping that this will solve my problem. Although the other possibilities I am hearing are either the power transistor or the coil packs. Either of these could definitely be the cause of me not having spark, but my question is would that cause the tach to not respond when cranking? It is my understanding our cars have a digital tach as opposed to a mechanical one. My brother mentioned that it is common for tachometers to be tied into the ignition coils. Anyone have any incite on this subject? I have yet to try my new CAS. I should get to that next weekend but if that doesn't work I would like some direction as to where to go next in addressing this problem. Thanks

 

[cOmpressor]

I don't think it's the coil pack, mine went bad ( sparks jumping all over ) and the tach still read fine.

 

[Nate]

Check the connection of the power transistor; if that doesn't work, the tach won't show anything and the car won't start.

 

[mitsu90]

have you spliced an afc to your ecu?? i had this problem and it ended up being a loose wire to the ecu.