Painless Performance EFI

The wires were pulled through the firewall. a rubber grommet was installed to protect them.

Routing of the wires and connectors was easy because Painless tags each one to where it goes. This one marked MAF goes to the mass airflow sensor. All the wires in the harness are also color-coded, using the original Ford factory code.

Once the wires were routed, plugging in the connectors was a snap. While installing the injector plugs, we found a slight problem. The harness is designed for the 5.0 engine, which has a different firing order than the 289. Since this Ford EFI is a sequential fire (one injector at a time sprays) instead of a batch fire (one bank of four at a time), half of the injector plugs had to be moved out of the harness to their respective firing order positions.

A couple of injector wires had to be lengthened. Wires were cut and spliced, then covered with heat shrink for their protection. The other wires were long enough and easily rerouted.

Other sensors (such as the mass air sensor shown) were wired.

With the new Ford coil mounted, the harness was plugged into it and the distributor.

The last wire in the engine compartment was the yellow main battery feed wire for the computer. It was attached to the Maxi fuse, along with other wires going to the chassis harness fuse block.

The engine wiring is completed. Fuel lines were next.

An electric fuel pump was purchased from Arizona TPI and installed on the rear of the fuel tank. Pieces of a rubber radiator hose were wrapped around it to help isolate noise. A special high-pressure hose was installed between the pump and the new steel lines. Double clamps were used on the pressure hose for a little extra safety. The wire for the pump from the fuel pump relay was routed and attached.