1987 Ford Mustang LX, 2D Hatchback, 5.0 E, AutomaticFACTORY OEM SERVICE PROCEDURE

Ignition System - TFI-IV: Operation

The TFI-IV distributor uses a Hall Effect switch mechanism to switch primary voltage and to trigger the discharge of high secondary voltage. Crankshaft position and engine load signal is supplied to the EEC-IV Electronic Control Assembly (ECA) to compute spark advance. Distribution of high secondary voltage is accomplished through a conventional cap, rotor, and spark plug wires.

Fig 1: TFI-IV "Closed Bowl" Ignition System (3.8L)
G54437Courtesy of FORD MOTOR CO.
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

Rather have a pro handle this?

A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.

Comes to youSame-day available12-month warranty
Get a Free Quote

No obligation. See pricing before you book.