dmstanl

I just a finished a 4.6 to 5.4 swap, turned the key and nothing. By debugging I have ruled out the started because the motor turns if I lay a screw driver across the bolts on the firewall solenoid. I have ruled out the firewall solenoid as I swapped it with my other f150 and it worked in that truck. The one that worked in the running truck did not solve the problem in the truck that I just did the swap in. I suspect the switch that recognizes the truck is in park. I tested the incoming volts at the firewall solenoid and received 0 volts when the truck is not in park and 3.90v when the truck is in park so it is recognizing that the truck is in park. I tested the incoming volts on my other truck (it has a clutch) and received 5V when I pushed in the clutch. This leads me two my questions:


1) Could the lower voltage at the solenoid cause it not to fire?
2) Does anybody know the minimum required voltage to get the firewall Solenoid to switch?
3) Is there any safety connections other than being in Park that I need to check


Any ideas as to the problem would be greatly appreciated.

TheBathTub

check your fuses, should be getting 12.5v or so at the relay and solenoid, low volts could possibly cause the solenoid or relay to not drop all the way not making a full connection. measure resistance between ends of your cables also to make sure they are reading 5 ohms or less higher than 5 will indicate breaks in the wires.