EFIconversionPics

EFI CONVERSION

Five years ago I converted my Fox body Mustang from carb to EFI and wrote a page about it with linked pics. This is a shortened version.

It has been a trouble-free addition to the car. Whereas the carbs always seemed to need constant attention, the efi self adjusts winter, summer, high altitude or low. One in tank fuel pump from the wrecking yard went bad and was replaced with a speedshop Holley. The third fuel filter was just put in, probably too early, but I was working under there.

There was a problem with the computer going lean all the time, but that was because I had a cam with the wrong firing order for the programming. I figured out a trick for that.

The engine with a carb. Good camera, poor scanner.

  The engine is an old style 302 with ported heads, flat tops, and a Performer 289 intake. When the engine was rebuilt the hot cam was replaced by a 'torquer' type. This purposely limited the revs in exchange for more mid-range.

  Various aftermarket carbs had been used, but now a '70s Motorcraft was on top.This carb is a bit of a frankenstein. Some parts resemble a carter, a quadrajet, or thermoquad. The accelerator pump is held UP by the linkage and a spring pushes it down. The secondaries have a piston that pushes against the gas, so they are hydraulically operated. It was the best all around carb I ever had with far better mileage than anything else.

  And I threw it out a few years ago.

I decided to collect parts until spring and do the conversion then.   I only knew the basics of fuel injection and never tried to learn more, so some reading on the internet was needed. I wanted to understand EFI thoroughly before it was put in the car.
At the self serve wreckers all the mechanical bits were removed, such as manifolds, injectors, and throttle. I also removed the computer and followed the wiring out to every device that was hooked to the computer. It is a lot of wiring compared to a carb setup, and took several hours. There was a big duffle bag full of stuff, and at the checkout the guy called it an intake and charged $12.00 for everything!
  Some serious cleaning and a few coats of automotive silver and it was beautiful.

   I searched a local ford dealers' manuals, found the right schematics, took them to the office, photocopied them myself, and then some assistant shop foreman charged me a dollar a page 'for his trouble'. (and I think he was half drunk too.)
  Anyway, there were 5 11x 17 sheets along with an enlargement of the computer area. Now I began to understand how it all went together. ( these early drawings showed a knock sensor, which the 5.0 never had! )

There are many more sites with drawings than when I did mine. Here are a couple.

http://www.veryuseful.com/mustang/tech/engine/

http://www.fordfuelinjection.com/

  A Saturday evening was spent down by the washer with the wiring harness. Every wire was traced from the EEC pins to every sensor, and tagged. In this way the wiring was cleaned up, trimmed to length, and consolidated into a stand alone harness with 2 positives (for EFI and fuel pump relays) and 2 grounds (for EFI ground and TFI anti-static). It looks like a lot of wire at first.
The harness had several wires left over, which were cut short and left in the firewall plug for some future use. I also recommend hooking up the harness to 12 volts beforehand and testing each plug. It's easier than fixing it in the car. Also ground everything to everything under the hood, and check old ground wires.

  The firewall had a round hole that needed to be oval to fit the EEC connector. I used a dremel with a cutoff disc to get the basic shape and then rounded it. The new rubber plug had another hole and a slot cut in it to get the old wiring back into place.
The wiring was laid out and all the sensors were added.

A small fuse box from a hyundai was added in the engine compartment. One fuse each for the EEC and fuel, and two for the electric fans I also added.

  A car that came with EFI has a pocket for the computer. Mine didn't. It could have been placed under ethe dash, or had the wires lengthened and stuck under the seat but a pocket was made in front of the passenger door.
After the fender was removed, the area was marked and cut out using an abrasive blade in a circular saw.
  Plate was used on the bottom half as it ties into the door hinge. The rest is sheet stock with folded flanges made for easier welding. It was then cleaned and undercoated. The sunroof drain moved to the antenna hole and a new hole was made for the antenna wire.   Inside, the same EEC plate was altered and a piece of wood spaced it away from the door bolts.

The TFI distributor had to be altered because it has a steel gear, which would destroy my old style camshaft. The old duraspark 302 dist. has a cast iron gear with a smaller hole. Some say drill it out to the bigger 5.0 size, but I found that an older 351 has the proper gear to use.

The only problem is getting it off without damage. ( Why does ford put them on so tight? GMs fall off after the roll pin is removed.) I bought an old dist., cut the shaft, heated the gear, and tapped it off. ( I also put a grease fitting in the TFI distributor)

  I found a stripped out 87 on stands with only the fuel lines and a DA1 computer. The 2 lines came out in one piece but had to be cut in half to get them home.
A propane powered half ton had a 'like new' external fuel pump so I decided to go with that. The pump was mounted on the panhard bar support using a bracket from a 280ZX. An inlet filter protects the pump and also acts as a small fuel reservoir, providing the pump with a few seconds of gas if the tank sloshes.
  This worked fine until the gas tank developed a rust spot and started dripping fuel. A newer tank with a built in pump was swapped in. The fuel sender had to be changed to a 1986 part to work with my earlier gauge.

The main fuel filter needed some thinking to mate with the external pump and the stock lines. I collected several examples with the same size outlets.
The Nissan is the same as the Ford except it's set up for rubber hoses. The Subaru was intially choosen as it allowed the most clearance with the exhaust. It was mounted in a mustang factory filter holder that I bolted to the floor of the hatchback.
  When I changed the tank I used a nissan filter. I forget which model.

  Finally, it was all together. Mainly. Despite knowing it should work, I wondered if it would. I hotwired the EEC and cycled the fuel pump several times, turned the starter, and it started. Yippee!

My engine has the old 302 firing order, so the injector harness had to be changed. This could be done at the EEC pins but I did it at the two 10 pin plug-ins, and cut off the plugs at the same time.
There is a problem with this re-ordering. I was having a problem with the engine running leaner and leaner everyday. I double-checked every sensor and they were okay. If I purged the computer it ran good again for a while. Then I tried unplugging the O2s and it ran better than ever.
  Soon after, I was informed on a forum that the computer can adjust each injector bank seperately, based on O2s. If it reads lean on the left, it richens up those injectors. But now some of those injectors are on the right! So the right gets rich so the EEC leans it out, but some of those injectors are now on the left! So the engine gets leaner and leaner.
I wondered if I could 'siamese' the O2s. People on forums gave long, loooong theoretical reasons why it wouldn't work. Well I tried joining the wires and it worked. I scotch-locked the two wires near the plug and it evened out the signal to the computer. Finally, it runs great.

  Some people say that EFI does not increase power. With my combo that was wrong. Power and torque are way up, and the 10 in clutch couldn't handle it. The engine revs quicker and higher. Temperatures are lower and more stable. Gas mileage in town is also up 35 to 40 percent! However I was a bit disappointed by the highway mileage. It was no better than my super-tuned carb. Oh well. The total cost to get the EFI initially running was a low $130.00! Coverting to a bigger clutch cost three times as much.

The engine with a carb. Good camera, poor scanner. The engine is an old style 302 with ported heads, flat tops, and a Performer 289 intake. When the engine was rebuilt the hot cam was replaced by a 'torquer' type. This purposely limited the revs in exchange for more mid-range. Various aftermarket carbs had been used, but now a '70s Motorcraft was on top.This carb is a bit of a frankenstein. Some parts resemble a carter, a quadrajet, or thermoquad. The accelerator pump is held UP by the linkage and a spring pushes it down. The secondaries have a piston that pushes against the gas, so they are hydraulically operated. It was the best all around carb I ever had with far better mileage than anything else. And I threw it out a few years ago.
	I decided to collect parts until spring and do the conversion then. I only knew the basics of fuel injection and never tried to learn more, so some reading on the internet was needed. I wanted to understand EFI thoroughly before it was put in the car. At the self serve wreckers all the mechanical bits were removed, such as manifolds, injectors, and throttle. I also removed the computer and followed the wiring out to every device that was hooked to the computer. It is a lot of wiring compared to a carb setup, and took several hours. There was a big duffle bag full of stuff, and at the checkout the guy called it an intake and charged $12.00 for everything! Some serious cleaning and a few coats of automotive silver and it was beautiful.
I searched a local ford dealers' manuals, found the right schematics, took them to the office, photocopied them myself, and then some assistant shop foreman charged me a dollar a page 'for his trouble'. (and I think he was half drunk too.) Anyway, there were 5 11x 17 sheets along with an enlargement of the computer area. Now I began to understand how it all went together. ( these early drawings showed a knock sensor, which the 5.0 never had! ) There are many more sites with drawings than when I did mine. Here are a couple. http://www.veryuseful.com/mustang/tech/engine/ http://www.fordfuelinjection.com/
	A Saturday evening was spent down by the washer with the wiring harness. Every wire was traced from the EEC pins to every sensor, and tagged. In this way the wiring was cleaned up, trimmed to length, and consolidated into a stand alone harness with 2 positives (for EFI and fuel pump relays) and 2 grounds (for EFI ground and TFI anti-static). It looks like a lot of wire at first. The harness had several wires left over, which were cut short and left in the firewall plug for some future use. I also recommend hooking up the harness to 12 volts beforehand and testing each plug. It's easier than fixing it in the car. Also ground everything to everything under the hood, and check old ground wires.
The firewall had a round hole that needed to be oval to fit the EEC connector. I used a dremel with a cutoff disc to get the basic shape and then rounded it. The new rubber plug had another hole and a slot cut in it to get the old wiring back into place. The wiring was laid out and all the sensors were added. A small fuse box from a hyundai was added in the engine compartment. One fuse each for the EEC and fuel, and two for the electric fans I also added.
	A car that came with EFI has a pocket for the computer. Mine didn't. It could have been placed under ethe dash, or had the wires lengthened and stuck under the seat but a pocket was made in front of the passenger door. After the fender was removed, the area was marked and cut out using an abrasive blade in a circular saw. Plate was used on the bottom half as it ties into the door hinge. The rest is sheet stock with folded flanges made for easier welding. It was then cleaned and undercoated. The sunroof drain moved to the antenna hole and a new hole was made for the antenna wire. Inside, the same EEC plate was altered and a piece of wood spaced it away from the door bolts.
The TFI distributor had to be altered because it has a steel gear, which would destroy my old style camshaft. The old duraspark 302 dist. has a cast iron gear with a smaller hole. Some say drill it out to the bigger 5.0 size, but I found that an older 351 has the proper gear to use. The only problem is getting it off without damage. ( Why does ford put them on so tight? GMs fall off after the roll pin is removed.) I bought an old dist., cut the shaft, heated the gear, and tapped it off. ( I also put a grease fitting in the TFI distributor)
	I found a stripped out 87 on stands with only the fuel lines and a DA1 computer. The 2 lines came out in one piece but had to be cut in half to get them home. A propane powered half ton had a 'like new' external fuel pump so I decided to go with that. The pump was mounted on the panhard bar support using a bracket from a 280ZX. An inlet filter protects the pump and also acts as a small fuel reservoir, providing the pump with a few seconds of gas if the tank sloshes. This worked fine until the gas tank developed a rust spot and started dripping fuel. A newer tank with a built in pump was swapped in. The fuel sender had to be changed to a 1986 part to work with my earlier gauge.
The main fuel filter needed some thinking to mate with the external pump and the stock lines. I collected several examples with the same size outlets. The Nissan is the same as the Ford except it's set up for rubber hoses. The Subaru was intially choosen as it allowed the most clearance with the exhaust. It was mounted in a mustang factory filter holder that I bolted to the floor of the hatchback. When I changed the tank I used a nissan filter. I forget which model.
Finally, it was all together. Mainly. Despite knowing it should work, I wondered if it would. I hotwired the EEC and cycled the fuel pump several times, turned the starter, and it started. Yippee! My engine has the old 302 firing order, so the injector harness had to be changed. This could be done at the EEC pins but I did it at the two 10 pin plug-ins, and cut off the plugs at the same time. There is a problem with this re-ordering. I was having a problem with the engine running leaner and leaner everyday. I double-checked every sensor and they were okay. If I purged the computer it ran good again for a while. Then I tried unplugging the O2s and it ran better than ever. Soon after, I was informed on a forum that the computer can adjust each injector bank seperately, based on O2s. If it reads lean on the left, it richens up those injectors. But now some of those injectors are on the right! So the right gets rich so the EEC leans it out, but some of those injectors are now on the left! So the engine gets leaner and leaner. I wondered if I could 'siamese' the O2s. People on forums gave long, loooong theoretical reasons why it wouldn't work. Well I tried joining the wires and it worked. I scotch-locked the two wires near the plug and it evened out the signal to the computer. Finally, it runs great. Some people say that EFI does not increase power. With my combo that was wrong. Power and torque are way up, and the 10 in clutch couldn't handle it. The engine revs quicker and higher. Temperatures are lower and more stable. Gas mileage in town is also up 35 to 40 percent! However I was a bit disappointed by the highway mileage. It was no better than my super-tuned carb. Oh well. The total cost to get the EFI initially running was a low $130.00! Coverting to a bigger clutch cost three times as much.