I have just completed installing a pi intake manifold on my 1997 4.6 bird. All vacuum lines and electrical leads appear correctly reinstalled. As I turned on my ignition to fire it up for the first time, I can hear the whine of my radiator cooling fans istead of the usual whirr of the fuel pump prime. Why is this happening? The fans were not touched when I removed the old cracked intake manifold. So now , with fans spinning , the engine just cranks and cranks without even a pop. The enertia button is pushed down , but I cannot hear the pump prime over the fan noise. I would like to know what is causing my fans to come on when I turn on the ignition. I am assuming the engine somehow thinks it is running hot and is operating the fans, but what do I undo to correct it? I cannot find any loose electrical leads. The sensor on the water line near the firewall is attached. I drilled and tapped the aluminum crossover and that connection is solid. Which could be signalling the fans? Could this cause a problem with ignition?