Hi I'm new to this forum and pleased to have this much more info and feedback to my disposal. I've been on an electrical hunt for some time now and I cannot seem to get my tach working. I just put a brand new crank sensor and truck already has external voltage regulator with a new\used PCM from ebay. What else could be causing this problem?

 

So I was messing with the plug for the cps and now my tach is working but my fuel pump is not.

 

Coincidence, because your fuel pump isn't electric. Unless it is, but with no signature information filled in we generally assume you're all stock.