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TFI Ignition Control with MegaSquirt-II

Thick Film Ignition (TFI) modules were used on Ford vehicles with distributors from the early 1980s to the mid-1990s. It was used on a number of Ford's engines, the EFI 5.0 engines in particular. The TFI module is a gray box fitted to the side of the distributor. It is about one inch wide, and about four inches long. The distributor itself uses a Hall effect sensor.

The TFI modules are available as Holley 891-105 or Accel 35368 (~$46), as well as from a number of aftermarket sources.

Installing the Ford TFI System

The connections are:

  1. GND: Ground.
  2. TACH: Coil control wire.
  3. PWR: Battery voltage input with ignition switch in run position.
  4. STRT: Battery voltage input with ignition switch in start (cranking) position.
  5. SPOUT: The timing control signal from your controller to the module goes on this wire.
  6. PIP: This signal provides the crankshaft position.

The other three pins on the side of the module are for the distributor's sensor. These pins are:
- signal,
- power,
- ground,
starting from the pin closest to the 6 pin external connector.

Note: this information is tentative. The MS-II/TFI setup has not been 100% verified yet.

First, be sure to use MegaSquirt-II code version 2.1 or higher. This code has the appropriate algorithm for the necessary 'trigger return' cranking parameter. Get the code here.

To install TFI with MegaSquirt-II, you connect:

V3.0 main board:

The PIP signal comes into MegaSquirt-II on DB37 pin number 24, the SPOUT goes out on pin #36.

Then in MegaTune, set:

Then set the maximum dwell duration to 8.0 milliseconds with no battery voltage compensation (set the five 'Duration at Voltage X' to 0.0 under 'Dwell Settings/Battery Voltage Compensation' in MegaTune.).



MegaSquirt® and MicroSquirt® controllers are experimental devices intended for educational purposes.
MegaSquirt® and MicroSquirt® controllers are not for sale or use on pollution controlled vehicles. Check the laws that apply in your locality to determine if using a MegaSquirt® or MicroSquirt® controller is legal for your application.
©2005, 2007 Bruce Bowling and Al Grippo. All rights reserved. MegaSquirt® and MicroSquirt® are registered trademarks. This document is solely for the support of MegaSquirt® boards from Bowling and Grippo.