Dan Marlowe's Mustang Web Page

Installation of Ford's SEFI System

Items required to convert Carb equipped '85 5.0 Mustang GT (Manual Trans) to SEFI

Items from ‘89 - ‘93 (Mass Air) 5.0 Mustang with manual transmission:
- Mass air unit and bracket
- Air inlet tubes and air cleaner assy (no silencer) (or K&N and Ram Air)
- Main wiring harness with power and fuel pump relays (passenger side kick panel)
- MAP sensor and bracket
- Computer for Mass Air

Items from ‘87 - ‘93 5.0 Mustang with manual transmission:
- Upper and lower intake with throttle body, EGR plate, fuel rails, injectors, fuel pressure regulator and intake wiring harness (with air charge temp sensor, engine coolant temp sensor, EGR position sensor, throttle position sensor and idle speed control) Don’t get the upper intake from an ‘86 model! The '86 had a small opening for the throttle body.

Items from any year EFI 5.0 Mustang with manual transmission:
- Oxygen sensors and wire harness
- Vapor canister and purge solenoid and lines
- Fuel pump and filter
- Fuel Pump relay and inertia switch (in hatch area)
- Transmission wiring harness with neutral and speed sensors (use existing one if equipped with Speed Control and shift light)
- Distributor and TFI module ('85 had roller cam, If installing into block without roller cam, you must change the gear on the distributor
- Fuel lines and filter (Buy new)
- Throttle cable and bracket
- Radiator shroud and overflow bottle (not required if mounting battery in non stock location)
- Thermactor Air Bypass and Diverter solinoids and bracket
- EGR Vacuum Regulator and bracket
- Coil and wire
- Windshield washer tank w/ pump (not required if mounting battery in non stock location)
- Clutch switch
- Fuel pump blankoff plate (from FMS)

Items from ‘86 5.0 Mustang with manual transmission:
- Fuel tank with level sending unit
- Speed sensor from transmission (use existing one if equipped w/cruise control)
- Speedo cable (use existing one if equipped w/cruise control)
- Heater hoses for AC or non-AC
- Fuel lines - 1/4 and 5/16 hydraulic brake tubing and fittings and FI hose

Some of the sensors are available from FMS in kit form. I chose to use all new sensors.
 

SEFI Installation Procedures

II. Drain radiator. Position engine at timing mark for #1. Remove distributor and intake. Remove battery & mount, starter solenoid and cables. Remove radiator fan and shroud, overflow/windshield washer tank and fuel vapor canisters (2). Remove air inlet tubes from inner fenders. Remove fuel pump and lines. Drain and remove fuel tank.

III. Remove thermactor controller. Unplug wires during removal, do not cut if possible. Remove the controller from the passenger kick panel, disconnect and feed the wires up through firewall. Remove the cover from the wire bundle and separate out the wires for the controller. Remove the vacuum switches from the both shock towers and the TAB and TAD solenoids from the firewall. Remove the Duraspark ignition unit, ballast resistor and coil harness. Separate out the wires so that all controller wires on the firewall side hang over the L fender with the remaining controller wires going into main harness into firewall on the driver’s side. Tag the following wires going into firewall on drive’s side:

W/R - oil press
R/W - water temp
Dark green/yellow dots - tach
Purple and Orange/Black +12v run only
White/Blue squares and Black/Purple +12V run and start
R/B +12V start
R/B +12V start w/ clutch depressed
Gray/yellow (brown at fuse link) +12V run only.

Leave all other wiring alone, including the blue oil level sender.

IV. Install lower intake and grounding straps (don’t use the cork gaskets at the front and rear of the lower intake, use silicone). Blank off fuel pump mount. Position crank at timing mark for #1 before removing old distributor. Position EFI distributor at #1 as shown in service manual photos)

V. Relocate battery and solenoid to the left side. My ‘85 had two holes for the battery box already in place. Install windshield washer tank into the existing air inlet hole in the L inner fender. Install EFI radiator shroud and tank. Cut a hole in the R inner fender for the air box. Mount the coil to the L inner fender.

VI. Install clutch switch. Use dielectric grease on all plugs. Install main EFI wire harness. Mount power relay, TAB & TAD, EVR and MAP sensor. Install O2 sensors and wiring harness. There are two 8 pin round connectors and one 8 pin rectangular plug that have to be connected to the chassis harness. Connect harness grounds but not power. Connect as follows (‘91 harness colors to ‘85 chassis colors):

A. 8 pin round gray (near computer)
1. Red is +12V to fuel pump inertia switch (opposite a ii)
2. Blue/Orange is pump on grounding wire (pin 22), connects to coil part of fuel pump relay with wire in d ii.
3. other 4 wires not used (terminate in two 2 pin round white air bag sensor connectors near mass air that won’t be connected)

B. 8 pin round brown (near test plug)
1. W/R oil press gauge to W/R
2. R/W water temp gauge to R/W
3. Red/Blue power in, start only connects to Red/Blue in harness (not clutch switch)
4. Red/Green power in start and run connects to White/Blue squares
5. White/Purple not used
6. Tan/Yellow Ignition coil neg. connects to Tach, Green/Yellow dots
7. Gray/Red connects to neutral switch then parallels on to dual clutch switch opposite Blue/Green in next step (neutral switch is R/Y dots in black 8 pin rectangular plug at front of center console) (switch is closed in neutral)
8. Blue/Green connects to neutral switch then parallels on to dual clutch switch and completes circuit with Green/Red above (neutral switch is purple in black 8 pin rectangular plug at front of center console)

C. 8 pin rectangular green (near computer)
1. White/Pink is oil level and not used if blue wire is left intact
2. Gray/Yellow O2 heater +12V run only to Gray/Yellow (brown at fuse link) use 12 gauge wire to run from L side under hood to R side passenger kick panel
3. Dark Green/Yellow (pin 19) fuel pump on feedback connects to relay with wire d iii
4. Dark Purple +12V A/C on
5. Pink/Orange trans speed sensor neg. connects to Black 8 pin rectangular plug black wire at front of center console
6. Gray/Black trans speed sensor pos connects to Black 8 pin rectangular plug green wire at front of center console
7. Pink/Green check engine light neg.

D. Additional wiring:
1. +12V start and run to check engine light
2. inertia switch to coil part of fuel pump relay opposite a ii
3. switch part of fuel pump relay to fuel pump with wire c iii
4. +12V battery (with 20 amp fuse) to switch part of fuel pump relay opposite wire d iii
5. ground fuel pump

VII. Install and connect TFI module. Install injectors, fuel rails and intake wire harness. Connect to main EFI harness. Connect A/C pressure switch (jump across if using aftermarket A/C unit).

VIII. Install upper intake, coolant lines, heater hoses and throttle cable. Install vapor purge canister, solenoid and lines from fuel tank to canister and from canister to intake. Install PCV hose. Connect vacuum lines.

IX. Install mass air, bracket, air box , filter and tubes.

X. Install fuel tank and lines. Use metal 5/16 brake tubes and fittings for the pressure line, and metal 1/4 brake lines for the return. Get Fuel Injection rubber tubing for the ends and clamp securely to the fittings on the tubes.
The fuel level sending unit didn't work with the stock guage. I had to remove the original one from the old tank and modify it to fit.

XI. Install check engine light. Install computer. Attach power to harness. Check for ignition spark and adjust timing (without fuel pump operating - pull the relay). Check computer codes. Turn ignition on and listen for fuel pump. It should come on for a few seconds and then shut off. If it does, then start and test run the engine. You might have to plug and unplug the computer a few times to get it to work.

Credit must go to Muscle Mustang and Fast Ford magazine, but that was about 50% of the research that was required. There were a lot of issues (particularly wiring) not addressed in the articles they ran on the conversion. My Haynes maunal provided enough info to complete the job.

The stock tachometer still works, as does warning lights that were installed.

The total cost was around $1500, but that's because I bought new sensors, computer, 110 lph fuel pump and a 75mm mass air meter. If anybody is interested I can email a complete part listing with prices.

The car really runs better. It now has massive low end pull. The car starts right up and keeps running. The power is a lot smoother. There are no power lags coming off idle, and I can instantly pass cars in traffic without downshifting. The price was high, but it was cheaper than a new car.

Dan Marlowe

Here are some photos of the complete installation: Click on any picture to see it full size. Full size pictures will load immediatetly.
 

The Installation	From the Right	From the Left
Wiring Harness	Fuel Lines	Battery
Throttle Body	Solenoids	Heater Hoses

Copyright 1998, Dan Marlowe. Unauthorized duplication permitted. Please give credit to where you found it.