Let me get the background info out of the way... I had a cracked piston in my A6 and instead of rebuilding it I got a Y8 from my buddy that only has 6500 miles on it but has been stored for 6 years. In the interest of keeping the swap simple and because I'm NOT trying to build it up (now or ever) I used everything from the A6 except the block, head (and internals) and exhaust manifold. I have carefully transferred the tranny, intake mani, dizzy, alternator and etc... over and transferred the 4g harness to the new motor. I have made only the following changes to the 4g harness: extended the radiator fan switch wires to the new location on the thermostat, extended the O2 sensor wire for the different location on the Y8. Per "Mechanic B's" (and multiple other sources) directions I have not hooked up the crank fluctuation sensor, knock sensor, or oil pressure sensor (located at the VTEC housing) That being said, all wiring from the 4G harness has been accounted for (no extra plugs) and the stock 4G ecu should be able to find everything it needs and nothing extra. The VTEC controller is an external RPM activated switch and relay (which shouldn't have any affect on the whether the car starts or not - and that is my problem). With everything back together (including fluids and a good battery) the engine was not cranking. I can hear all the normal sounds from the fuel pump to the starter engaging the flywheel but alas, it does not turn over. I had Autozone test my starter (good) but tried a new one anyway which produced the same results. I unhooked, checked and rechecked all my connections, put it back together again and then it would crank (but not run) when I tried to start it. I would expect some trouble for an engine that sat for that long. I checked to make sure it wasn't seized by turning the motor over by hand and that was fine. I thought that I was making progress because at least now it was cranking and then for no reason it stopped cranking and doing what it was doing before. I checked the battery and all wiring again and still nothing. The very first time I tried to start it after the swap I had the starter from the y8 in but switched it out for the old one after a quick check revealed that they were different starters. Could this have damaged something? What and how would I check it. Does anyone know what's up? It seems too coincidental that a clutch safety switch would be faulty that started at the exact time that I swap a motor. Something has got to be faulting something somewhere right? No bad fuses, the main relay appears to be functioning. The very first time I tried to start it after the swap I had the starter from the y8 in but switched it out for the old one after a quick check revealed that they were different starters. Could this have damaged something? What and how would I check it.