This page exists to contain all of the information I have on doing a Ford EFI swap and was started as a separate page for doing this swap on my 1964 Ranchero. Most of the information that was originally on that page has been moved here. This page is based on research via Google and lots of web sites, in particular the fine folks over at http://www.fordfuelinjection.com/.
The basic idea is to take the entire fuel injection setup - intake manifold and all - from a 1989-1992 Mustang 5.0 and drop it onto an earlier Ford 302 (or similarly compatible) engine. The 1989-1992 engines offer all of the desirable pieces for this swap, though various parts can come from earlier and later vehicles, these years are what contain the "complete" system you want to use. It's a mass airflow style system and is readily adaptable for various swap situations.
If you need to use this on a 351-style engine, a Ford Explorer 5.8L lower intake is needed in place of the 5.0L lower intake used on the Mustang.
All parts are from a 1989-1993 Mustang unless listed otherwise. This stuff is constantly up for auction on eBay and readily available in wrecking yards, so there is zero pressure to "buy today". Take your time and gather all of the parts you need before you start performing the swap on your vehicle.
Engine Compartment and Computer Wiring
This is a typical 1989-1993 Mustang EFI engine compartment wiring harness. It has the AC compressor harness extended off the front driver's corner (bottom right), the O2 sensor and oil level sensor harness extending off the front passenger's corner (bottom left, extends out of picture), the computer connection and interior green wiring connector (left middle area), the grey and black body wiring connectors in the engine compartment (top right area), and the AC WOT cutout relay (middle area, to the right of the 60-pin EEC connector). For my 1979 F100 conversion, I needed to move the main power hookup from the stock Mustang location on the driver's side front to the passenger's side front, so I had to un-tape the entire harness to change this. I was also putting the firewall entry location in the middle of the vehicle instead of the far passenger's side that the Mustang uses, so I had to adjust for that as well - mainly by sliding the large rubber grommet along the harness towards the computer and using less harness inside the vehicle. I will have to double the harness back on itself in the engine compartment to do this without cutting any wires, but it will work for my needs in my 1979 F100. The rest is basically just re-taping the harness back up after the main power feed wire is moved from one side to the other.
Here's a close-up of the self test connector and the grey and black body wiring connectors. These three connectors end up near the driver's side hood hinge, exactly where depends on how you lay the harness into your specific vehicle. This is where most of the external connections to the EFI harness get made at.
Here's a close-up of the grey body connector in the engine compartment.
Here's a close-up of the black body connector in the engine compartment.
Here's a close-up of the computer connector, green connector, inside ground connection (computer case ground + shielding ground for the TFI signal wires), and the main EEC power relay. The green connector is where the remainder of the "external" connections to the EFI harness get made at (in this case, those inside the passenger compartment), aside from power and grounds.
This is the "body" side of the grey connector after it has been disconnected from the EFI harness. The wires you see here are the wire stubs in the previous pictures of this connector. You will need to hook these wires to other wiring in the vehicle to make the EFI system work. The wire colors for the wires, in order from left to right starting at the top left wire in the picture, are below. Your wire colors may vary, but the positions in the connector should be constant on most (if not all) of the Mustang EFI engine compartment wiring harnesses.
This is the "body" side of the black connector after it has been disconnected from the EFI harness. The wires you see here are the wire stubs in the previous pictures of this connector. You will need to hook these wires to other wiring in the vehicle to make the EFI system work. The wire colors for the wires, in order from left to right starting at the top left wire in the picture, are below. Your wire colors may vary, but the positions in the connector should be constant on most (if not all) of the Mustang EFI engine compartment wiring harnesses.
This is the "body" side of the green connector after it has been disconnected from the EFI harness. The wires you see here are the wire stubs in the previous pictures of this connector. You will need to hook these wires to other wiring in the vehicle to make the EFI system work. The wire colors for the wires, in order from left to right starting at the top left wire in the picture, are below. Your wire colors may vary, but the positions in the connector should be constant on most (if not all) of the Mustang EFI engine compartment wiring harnesses. Note that multiple wires are not present in this connector - those positions have been noted in the list below. Your wiring harness may have wires in these locations, but if there is nothing connected to them on the EFI harness side, then you don't need to use them, and can even remove the wires from the connector if desired.
Fuel Tank and Frame Wiring
This is a F150 fuel tank wiring harness that I used to control the fuel pumps on the EFI conversion on my 1979 F100 project. I started with a full frame wiring harness from a 1989 F150 as the basis for creating this harness. I first removed all of the tape and harness protection, then removed the terminals from the connectors at each end of the harness, and then removed just the wires I needed from the original harness. Which wires to remove from the end connectors was dictated by what I needed that was connected to those connectors. I left the external fuel pump connector and and both gas tank connectors intact (including the second gas tank connection, just in case) and did not even untape the harness in those areas. There was an extra ground connection at the rear of the harness that I left around "just in case" I needed it. There were a number of factory splices in the harness than I left alone - including the rather odd splicing of black to orange for the ground wires going to the fuel tank connectors. After I had just the wires I needed, I re-taped the harness and then taped the extra gas tank connector to the main harness in case I needed it later.
At the front of the harness, I was left with just six wires, and I can put them back into an original style wedge lock connector to mate this harness with the rest of the wiring later on. The wire colors and functions for all six wires that come to the front of the harness are listed below for reference. The last two (in italics) are specific to the front tank and although I did not use them on my 1979 F100 conversion, they're in the original harness and I left it in mine to keep from cutting things up needlessly. I'm noting it here for completeness and in case someone wants to do the full dual tank conversion - it not hard to wire this up to a DPDT fuel tank switch. (One pole controls which fuel level sender to connect to the gauge, and the other pole controls which low pressure in-tank pump gets power from the fuel pump relay.) Also, note that the ground wire is one size larger than the others since it carries the return current from multiple things.
Fuel Line Connections
Ford used a number of different connectors and sizes on it's various fuel lines in different fuel injected vehicles. The ones I used were from F-series trucks and Mustangs. Ford used funky nylon fuel lines along the frame on some vehicles, with "push lock" fittings at the various connections. The fuel rail connections were typically "spring lock" fittings.
These are typical Ford push lock fittings from a 1987 F150. Note the larger connection on the right hand fitting, both for the hose barb connection and for the push-lock (inside) connection. The nylon lines would be on the barb end from the factory. The smaller hose barb is a 5/16" hose, and I think the larger one is 3/8" hose. I was able to connect standard EFI fuel hose (the real high pressure stuff) to these with hose clamps. In my case, the larger hose and fittings were used for the feed lines from the tank to the accumulator/dual tank switching valve, and then to the high pressure fuel pump.
The interesting gotcha I found was that the high pressure pump and filter used the smaller sized lines and connectors, which means that the connector leaving the accumulator was a hybrid of a large push lock fitting and a small hose barb end. If using these fittings for custom work - like on my 1979 F100 project - that's a pretty important fitting to grab and save! There are also a limited number of straight and 90 degree fittings in each fuel system, and you may need to grab some from multiple donor vehicles to get what you need, or buy them new if you can find them. I had a pile of lines and fittings from three different vehicles, so I just cut the nylon lines off and used the fittings with hose and clamps to make up my system. I tried to re-use the nylon line, but gave up. It can be done, but it's a nightmare to heat properly and get over the fittings. If you do hook up fuel hose to these fittings, make sure you use high pressure fuel line everywhere on the feed side of the fuel system. The return line can use standard low pressure fuel hose. The higher pressure of the EFI system will quickly rupture standard low-pressure fuel line. There's a reason EFI fuel hose is more expensive - it has to be a lot stronger to handle the pressure...
Here's another pair of Ford push lock fittings, this time 90 degree fittings, with nylon hoses still attached. You can clearly see the larger hose size on the left hand fitting in this case. These push-lock fittings also have their plastic retaining clips installed in them, ready to push onto and lock to whatever is needed. Don't mangle or lose these clips - you'll need them to re-attach the lines. You can get replacement clips if needed. I think they are all the same size.
These are Ford spring-lock fittings, used to attach the fuel lines to the fuel rail on the engine. These are male fittings came out of a 1987 F150, and had nylon lines attached to them. Both have the same size hose barb fittings - 5/16" - and you can clamp standard size hose over them for custom work (again, use the proper high pressure line everywhere but the return line). Note that they have different size fittings on the spring-lock end so you can't hook things up backwards by mistake and feed 50PSI of fuel into the back side of the pressure regulator. The larger one is the feed to the fuel rail and the smaller one connects to the return side of the fuel rail. This is important when making up custom lines - don't get it reversed. Make sure the fuel pump feeds the fuel rails and the return line is hooked up to the pressure regulator outlet.
The clip in the third picture is a special retaining clip used to ensure nothing vibrates loose - it clips over the barrel (receiving end) of the spring-lock fitting and over the larger center section of the fittings in the first two photos. The plastic clip and short plastic wire keep the clip tethered to the fuel rail when it's removed so they don't get lost during service. Nifty, and a nice safety feature to keep intact. Having a fuel line back out of a spring-lock fitting and spray 50PSI of fuel on a hot engine could put a serious fireball on your agenda. They're annoying (well, no more so than the spring-lock fittings themselves), but you should re-install them after any fuel line service.
The female Ford spring-lock fittings are found on the ends of the fuel rails, and on the frame connector lines on the Mustangs. If you want to hook up to the Mustang fuel rail extensions, you need these. You can get these out of a junkyard or parts car, but that's a pain unless you get lucky - I needed two for my 1979 F100, and I only had one that came with a used engine I had purchased.
If you need to buy these fittings new, Mustangs Unlimited carries them but they are a whopping $18 each. Search for "springlock", or the various part numbers - RMP19 (small female), RMP20 (large female), RMP21 (small male), or RMP22 (large male).
Page last updated 06/26/2009 12:07:54 PM