2005 Mazda 6s 3.0 no start, no crank

[stitch1717]

Hey I just bought a 2005 mazda 6s with the 3.0 v6 and 5 speed transmission. The guy i got it from said the motor was making some loud knocking noises and then it sat in his driveway for around a year without starting again. I got it towed home, charged the battery (tested fine at 650cca) and tried to start it, i push the cluch in and all the lights come on but it doesn't try to crank or anything. no theft light on the dash, I can't hear the fuel pump prime when the key is first flicked forward and there is no power going to the pump it's self. When i started looking into a possible starter issue i found a broken small wire going to the starter, fixed that and nothing changed, i pulled the front 3 spark plug and used a screwdriver to cross the starter over it would crank over but there is no spark also. I swapped all similar relays and nothing has worked. I also ran a small jumper wire across the fuel pump relay and i can get the pump to turn on but still no start. i noted that the eng+b 7.5 amp fuse blows pretty much as soon as i hook the battery up and if i unhook the ecu connector (under the dash held in by a 10mm bolt) the fuse no longer blows. Could i have a ECU issue? i cant find any info on the small 7.5a circuit.
I figured i'd come here before i got it towed to the dealer, because if it does need an engine (very possible) i dont want to have to tow there then back home again just to put an engine in it.. Any kind of help would be greatly appreciated!!