Ford EFI Swap
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Overview

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/.

For general-purpose EFI information, please refer to my EFI Basics page.  For GM TPI systems, please refer to my GM TPI Swap page. For GM TBI systems, please refer to my GM TBI Swap page.

 

Swap Details

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.

 

Parts List

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.

Part Sugg. Cost Source Details/Notes
Air Filter   eBay or new Mount a K&N style filter onto the front of the MAF sensor, or create a custom cold air intake system if desired. Factory air box will not work in retrofit applications.
Fuel Pump Inertia Switch   eBay or junkyard Turns off fuel pump in case of crash. A "must have" safety feature!
Low Pressure Fuel Pump $60-$90 New Carter P4070, P4600HP, or similar.
High Pressure Fuel Pump $120 New Carter P74028 or similar.
Air Intake Tubes   eBay or junkyard These are the flexible rubber tubes that go from the from air box to the MAF sensor and from the MAF sensor to the throttle body. Get clamps with hose. Can be replaced with an aftermarket cold air intake kit if desired.
MAF Mounting Bracket   eBay or junkyard I got tired of hunting for this and just outbid everyone to win this auction. I really could have gotten these for much less if I had more patience.
MAF - Mass Air Flow Sensor   eBay or junkyard Get mounting bracket along with the sensor.
Fuel Filter   New  
Lower intake $75-$150 eBay or junkyard Needs ACT mounting boss already drilled and tapped. Suggested cost is for a package with upper + lower intakes, injectors, fuel rail, and throttle body.
Upper intake   eBay or junkyard 1986-1993 Car and 1996-2001 Explorer suggested for clearance issues
Intake Cover Plate   eBay or junkyard Name plate that goes on upper intake manifold. Purely cosmetic.
Fuel Injectors   eBay or junkyard Orange 19 lb/hr suggested. (Tan = 14 lb/hr, Blue = 24 lb hr)
Fuel Rail   eBay or junkyard Drivers side regulator preferred. Regulator side must match throttle body side. Use return style from before 5/3/1999.
Fuel Pressure Regulator   eBay or junkyard  
Springlock Fuel Line Fittings   eBay or junkyard Get Nylon fuel lines and cut the ends off. Remove the remnants of the nylon lines and you have a Ford springlock fitting that will accept a standard rubber fuel hose.
Coolant Hard Lines   eBay or junkyard Mounts to intake, provides throttle body warm-up lines and sanitary coolant hose routing. Get them with the intake if possible.
ECT - Engine Coolant Temp Sensor   eBay or junkyard  
ACT - Air Charge Temp Sensor   eBay or junkyard  
Throttle body $20-$50 eBay or junkyard 1985-1993 Mustang will work.
TPS - Throttle Position Sensor   eBay or junkyard  
IAB - Idle Air Bypass   eBay or junkyard  
Computer and Mounting Bracket $75-$125 eBay or junkyard Codes A9L, A3M, A3M1, D3D1, S0Z, A9S, A9M, A9P, C3W, and C3W1. X3Z is not preferred, but acceptable if cheap.

I got an A9P computer.

"Body" Wiring Harness   eBay or junkyard Build from scratch or buy used to start with.
O2 Sensor Wiring Harness   eBay or junkyard Build from scratch or buy used to start with.
Ignition coil $10-$25 eBay or junkyard Aftermarket replacements available, but not required. Factory EFI units work just fine and are dirt cheap.
BP - Barometric Pressure Sensor   eBay or junkyard Similar to MP Sensor used on earlier SD systems, but left open to the atmosphere.
Engine Wiring Harness   eBay or junkyard Build from scratch or buy used to start with.
HEGO - Heated Exhaust Gas Oxygen Sensor $35-$50 each New Buy new units. Two needed - one per side.
Distributor $20-$100 eBay or junkyard Need to figure out how to interface with an MSD box. Must have TFI module on distributor.
TFI Ignition Module   eBay or junkyard May not be needed with MSD ignition setup?
VSS - Vehicle Speed Sensor   eBay or junkyard Must provide speed signal. Retrofit applications must also drive a mechanical speedometer cable.
VSS and Transmission Wiring Harness   eBay or junkyard Build from scratch or buy used to start with.
Throttle Cable   eBay or junkyard EFI uses a different length and hookup style than a carb
Throttle Pedal   eBay or junkyard My original linkage and pedal use a solid rod, so it all might need replacement. Grab as much as you can at once in case you need it later.
EGR Valve   eBay or junkyard  
EGR Vacuum Regulator   eBay or junkyard  
EGR Position Sensor   eBay or junkyard  
Thermactor Air System n/a eBay or junkyard Smog-only. Not needed for pre-smog-era vehicles.
Assorted Vacuum Solenoids and Hoses   eBay or junkyard Grab everything you can while you're there. You likely won't use all of it, but leaving the Thermactor air system solenoids hooked up but not connected to any vacuum lines is a cheap way to fool the computer into thinking the emissions goo is there and working. The vacuum lines are nice plastic pieces with rubber ends meant to last for years, so get them while you're there.
KS - Knock Sensor n/a eBay, store, or junkyard Can't find this mentioned on any of the diagrams or parts lists. It appears to not be used on Mustang EFI systems, even though http://fordfuelinjection.com/?p=10 and http://fordfuelinjection.com/index.php?p=34 show that some Ford EFI systems use them...

 

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.

MustangMAFEFIHarness001.jpg (2314074 bytes)

 

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.

MustangMAFEFIHarness002.jpg (2191412 bytes)

 

Here's a close-up of the grey body connector in the engine compartment.

MustangMAFEFIHarness003.jpg (1988421 bytes)

 

Here's a close-up of the black body connector in the engine compartment.

MustangMAFEFIHarness004.jpg (2115108 bytes)

 

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.

MustangMAFEFIHarness005.jpg (2209927 bytes)

 

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.

  • Black with yellow stripe - Not connected in EFI harness, ignore.
  • Pink with light blue stripe - Not connected in EFI harness, ignore.
  • Dark green with yellow stripe - Tachometer signal wire, connect to tachometer if you have one.
  • Orange with black stripe - Not connected in EFI harness, ignore.
  • White with pink (or possibly red) stripe - Oil level sender, not used in most retrofit applications.
  • Green with purple stripe - AC request, connect to AC switch under dash if you have AC.
  • Red with blue stripe - Start power, connect to starter solenoid trigger wire.
  • Red with green stripe - Ignition power, connect to ignition powered wire, usually previous coil power feed.

MustangMAFEFIHarness006.jpg (1401447 bytes)

 

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.

  • Red with white stripe - Temp gauge sender, connect to original temp gauge sender wire.
  • Blue with yellow stripe - Automatic transmission only. If automatic trans O2 harness is used, comes from pin #30 on the 60-pin EEC connector, the manual trans O2 harness connects this to nothing. Connects to the ignition switch side of the NDS through a diode to prevent back-feeding. (Diode is shown in various factory diagrams) The computer can tell if the car is in neutral or drive via the resistance to ground on pin #30. The starter solenoid has a small but noticeable resistance to ground when the NDS switch is in park or neutral, and it's an open connection in reverse or drive. This tells the computer how to idle the engine and react to certain off-idle and dead throttle conditions.
  • Yellow with red stripe -  Not connected in EFI harness, ignore.
  • Pink with black stripe - Fuel pump monitor, comes from pin #19 on the 60-pin EEC connector, connect to the main fuel pump feed wire after the fuel pump relay. EEC uses this to monitor the fuel pump power to see if the relay is working OK and the pump actually has power.
  • White with red stripe - Oil pressure gauge sender, connect to original oil pressure gauge sender wire.
  • White with pink stripe - Manual transmission only. If manual trans O2 harness is used, comes from pin #30 on the 60-pin EEC connector, the automatic trans O2 harness connects this to nothing. Connects to the non-ground side of the NGS and CES switches. The NGS and CES switches are wired in parallel and prevent engine from starting except with clutch pedal depressed or the shifter in neutral, and help the computer tell if the transmission is "in gear" so it knows how to idle the engine and react to certain off-idle and dead-throttle conditions. The other side of the NGS and CES switches connects to pin #46 of the 60-pin EEC connector, which is the signal return/ground. In my case, goes to O2/oil level harness as a white with purple stripe wire, and in my O2 harness it loops back to the main harness without connecting to anything else in the O2 harness. This "loop back" connection is what determines a "manual" or "automatic" wiring harness - it's all in the O2 sensor harness.
  • Green with white stripe - VSS positive (+), connect to positive wire from VSS.
  • Orange with yellow stripe - VSS negative (-), connect to negative wire from VSS.

MustangMAFEFIHarness007.jpg (1606668 bytes)

 

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.

  • Empty location - Not connected in EFI harness, ignore
  • Black with white stripe - Clutch switch/NGS (neutral gear switch), comes from pin 46 on the 60-pin EEC connector, connects to the ground side of the NGS and CES switches. The NGS and CES switches are wired in parallel and prevent engine from starting except with clutch pedal depressed or the shifter in neutral, and help the computer tell if the transmission is "in gear" so it knows how to idle the engine and react to certain off-idle and dead-throttle conditions. The other side of the NGS and CES switches connects to pin #30 of the 60-pin EEC connector, after being routed through the black connector (above) and through the O2 harness, if it is a manual transmission O2 harness. On automatic transmission O2 harnesses, this connects to nothing.
  • Empty location - Not connected in EFI harness, ignore
  • Tan with no stripe - MIL (Malfunction indicator light) also known as the "check engine" light, connect to negative side of MIL, positive side of MIL goes to fused ignition power
  • Grey with yellow stripe - HEGO (oxygen sensor) heater power, connect to fused ignition power
  • Empty location - Not connected in EFI harness, ignore
  • Tan with green stripe - Fuel pump relay control, connects to pin #22 on the 60-pin EEC connector, connect to negative (ground) side of fuel pump relay coil
  • Red with no stripe - Fuel pump relay monitor, connects to pin #57 on the 60-pin EEC connector, connect to positive side of fuel pump relay coil

MustangMAFEFIHarness008.jpg (1607092 bytes)

 

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.

  • Black - Ground for everything, all three fuel pumps plus both fuel level senders
  • Pink with black stripe - High pressure fuel pump feed
  • Brown with white stripe - Rear low pressure fuel pump feed
  • Yellow with blue stripe - Rear tank fuel level sender
  • Red - Front low pressure fuel pump feed
  • Blue with yellow stripe - Front tank fuel level sender

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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...

FordEFIFuelLineConnectors01.jpg (1997582 bytes) FordEFIFuelLineConnectors02.jpg (2239940 bytes)

 

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.

FordEFIFuelLineConnectors03.jpg (1902990 bytes) FordEFIFuelLineConnectors04.jpg (2131195 bytes)

 

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).

FordEFIFuelLineConnectors05.jpg (2124327 bytes) FordEFIFuelLineConnectors06.jpg (2484047 bytes) FordEFIFuelLineConnectors07.jpg (2190139 bytes)

 

 

 

 


Comments? Kudos? Got some parts you'd like to buy/sell/barter/swap? Nasty comments about my web page so far? You can email Mike or Debbie.

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Page last updated 06/26/2009 12:07:54 PM