I'm new to the 87-91 Ford pickups, I usually deal with older Fords without all this wiring, but a few days ago a buddy of mine bought a 1991 F150 4x4 with a 300 inline 6 with a 5 speed transmission. The engine was missing on two cylinders and would hardly run. He had a donor pickup, a 1988 F150 4x4 with a 302 automatic transmission.

I've done tons of 70's-80's engine swaps so swapping the engine was no problem. We had the 302 running in the 88, we did the engine swap, and realized that the wiring harness's were no where near the same, luckily we kept the 88 wiring harness and installed the whole 88 setup from front to rear into the 91. After hooking everything up and getting everything into place we attempted to start it.

Well everything on the pickup functions, everything has power, brake lights, inside lights, horn, blinkers, heater, everything, but when you turn the key to start it, nothing happens, nothing, not a click or anything. Did we hook something up wrong? We wondered if since the wiring harness we installed into the 91 had a Automatic and its looking for the neutral safety switch? Could we unhook a sensor and would that fix this? We also tried bypassing the solenoid with the key on and it still does nothing. All the ignition components worked in both pickups before the swap, but it will not crank over now.

I'm new to all this wiring and harness's and stuff so I'm totally lost, my buddies Dad said he did a swap like this at some point and he said he just kept the swapping engine's wiring harness and hooked it up and it ran fine but we're not that fortunate. Does anyone have any insight at what we might have done wrong?

 

I would think getting the engine to spin by bypassing the solenoid would be pretty cut and dried. Do you have the ground cable hooked up right? Are you sure the starter didn't get jarred during the swap and quit working?

 

well just to be sure it was grounded properly we took a jumper cable and hooked it to the negative and hooked it to the engine, and it also has a extra negative jumper to the starter bolt. We pulled the starter and left it to the side, it shouldn't have be jarred I don't think.