Ford CFI (throttle-body, aka TBI in the Chevy World) Install on a '68 Bronco:
What I had:
302, points, 2bbl Motocraft carburetor, cagle fuel pressure regulator,
edlebrock 4 bbl intake--ran great, many people thought I was injected
because the 2bbl ran so well.
What I did:
NOTE: If you aren't familiar with what goes where, take some masking tape
and label everything as you take it off the donor vehicle. IE, the wire for
the O2 sensor, the alternator connection, the A/C connection (I didn't use
this but we spent an hour tracing the colors on the wiring diagram till we
figured out it was for the A/C and I wasn't going to use it.)
Took the intake up off of an '84 Lincoln Town car including: dist, coil,
wiring harness, computer, intake, throttle body, alternator, all sensors
(MAP, O2, etc.), all relays (fuel pump relay, computer relay, and one
other relay I can't remember the name of right now). If you can get the heads
too, get them. The water ports are much bigger than the stock bronco heads and
aid in cooling the bronco big time. We also took the reset switch that is
located either in the trunk, under the passenger seat, or under the dash on
the passenger side. I don't know exactly what it is called (inertia switch),
but in case of a crash, it cuts off the fuel pump and must be reset. I
chose not to install this because what I do on the trails can be construed as a
crash by the computer.
We (meaning I assisted my friend RD who is the guy who figured everything
out) then took the intake up off of my stock block. Be sure to put the
number one cylinder on TDC, before you reinstall the distributor.
Installed the Lincoln intake, dist, and throttle body. Laid out the wiring harness
just like it came off the Lincoln and plugged in all the connections just
like we unplugged them from the Lincoln.
The computer was mounted in the driver's floorboard area, right to the
outside of the brake booster bracket from the
engine side. The hole is about 1.5 inches by 4.5 inches. (Note: the computer
is mounted by sandwiching the connector from the harness through the
firewall to the computer. The bolts are a 10 mm nut and can't be tightened
or removed with anything but a 10mm. When we were pulling everything at the
junkyard, we didn't have a 10 mm and it took almost 2 hours just to get
the computer out.) Also note that these 2-10mm nuts and the computer mount to
the firewall is what grounds the whole system. I was having some cutting out
with the injection and it was just the nuts working loose and the computer
losing its ground.
I then spent a few hours down at the local library. There should be an
automotive section and they have wiring diagrams for the different year
vehicles. 1984 was a changeover year, so I ended up using wiring diagrams
from an '84 Lincoln town car, an '83 Mark IV, and '85 LTD, and an '85 Grand
Marquis. Ford is pretty good about the wire coding and coloring, so you just
have to trace what you need.
NOTE: DO NOT use degreaser or any type of paint thinner, gas, brake clean,
etc., to clean the wires. They are all the same color to begin with and Ford
paints the colors on them. I had to break apart the harness to figure out
what the colors were because I used brake clean to get the grease off and
it also took the paint off the wires.
If I remember correctly there are only about 6 wires that actually have to
be spliced into the bronco. 2 or 3 have to go to the start position on the
key, and the rest have to have juice when the key is in the run position. I
ran the juice ones off the starter solenoid just like it was on the Lincoln
(these were fusible links built into the harness). Having the wiring diagram
and a test light/meter when you are doing this is important. Also, having
someone small enough to get under the dash and get the right start and run
wires off the key switch is helpful. I'm too big to even get my head up
under the dash. Also, it helps to remove the fresh air vent from the
driver's side. With the vent out, you can see the back of the dash pretty
good.
You have to mount the MAP sensor relay, the fuel pump relay and the computer
relay. The fuel pump and computer relays are mounted together in the Lincoln and I removed the bracket from the Lincoln. I mounted these to the inner fender on the driver's side, just behind the fender well (again, the same location they were mounted on the Lincoln. The MAP relay was mounted on
the firewall on the passenger side, right next to the external regulator for
the alternator.
Also, before you can start it up, you have to install an electric fuel pump,
run fuel lines and a return line. For the pump, I use a high flow,
high-pressure pump for an '86 F250. Pep Boys carries the good Fed/Mogul
pumps, but have them price check with Autozone (who carried the cheap ones)
and you'll save $40 ($60 vs $100).
I mounted the fuel pump to the frame rail right in front of the rear gas
tank. The pump comes with a piece of rubber to help with vibration and
noise. After trying to fab a custom mount for it, I was staring at the old
intake and carb lying on the workbench and realized that the stock coil
mount looked to be about the right size for the fuel pump. Sure enough, it
fits perfect with the rubber insulator supplied with the pump. Also, you
only have to drill one hole in the frame to mount the pump. I used a
self-tapping screw and a high-speed drill and a lot of elbow grease. Frames
are a bitch to drill. You have to run a positive wire from the fuel pump
relay back to the fuel pump. I ran it down the frame rails all the way to
the pump and put some wire loom over it and zip tied it to the fuel lines.
Fuel lines.
I chose to run hard lines the whole way. Though you can use
rubber, but be sure to get the high-pressure fuel line hose from a hose
shop. It is expensive, but it works. I used 3/8 brake line for the main feed
and 5/16 for the return. I have a rubber connection right by the tranny
where the line comes down from the throttle body to allow for engine to
frame movement and flex. It is about 6 or 8 inches long. For the return
line, I installed a brass T into the overflow line in the rear tank. For the
front tank, I had a bung brazen into the sending unit and I screwed a hose
barb into the bung. I later removed the front tank when I cut the rockers,
but it worked well while it was in there. Right in front of the pump I
installed an electric tank selector switch. Again, I used an '86 F250
switch. It has both main and return lines for two tanks (3/8 and 5/16 respectively). I also got the
dash switch for an F250. The wiring instructions
included with the switch are good and work. I used rubber high-pressure fuel
line hose from the tank to the selector switch and to the fuel pump. I also
installed a high flow fuel filter between the tank and the fuel pump (be
sure to mount it to flow the right direction). The pumps are really
sensitive to crap coming from the tank. I change fuel filters about 6 times
a year. They only cost $2 each and are cheap insurance IMO.
One thing to note on the fuel pump: I have had excellent luck with the fuel
pump. It has been on there for over 2 years with no problems. However, don't
run your tank dry. I only did this once (about a month ago) and after two
hours of sitting and cranking and sitting and cranking, the pump still
wouldn't prime. Finally, I had a buddy tow me home. After bouncing over the
street for 10 miles, and sitting over night, it finally primed and has
worked fine ever since. You have to be careful, because the gas flowing
through it cools the pump. Trying to prime it after it ran dry, I burnt my
finger when I touched it after about 30 minutes of cranking.
I am going to install a pusher pump in between the tank and the
high-pressure pump, when I do the motor swap. A
pusher pump is a high volume, low-pressure pump. They prime really easy,
unlike the high-pressure pumps.
Before you hook all the fuel lines up, it is a good idea to test the fuel
pump to make sure the relay is activating it when you turn the key on, and
that it is flowing the right way. IE, pushing fuel towards the motor, not
pulling it back into the tank. Believe it or not, I have seen many people
bring their new FI motor conversions into my friends shop and the whole
problem is they installed the fuel pump backwards.
When you get everything hooked up, you can turn the key to the run position
and you should be able to hear the fuel pump cycle. Do this a few times till you hear the pump fill with gas, and then proceed to turn the motor over. It should start pretty easily. It
will run rough at first for a couple of reasons. 1) The computer has been
unhooked from the battery and therefore will reset itself into limp home
mode, so it has to relearn how to run; and 2) since you just put in a
different distributor, you will have to adjust the timing.
After you get it running, I mounted everything permanently, ran wire loom
and zip tied everything nice and neat. I also put on new plug wires, cap and
rotor. Oh yeah, just remembered. You have to also get a vacuum hose diagram
from the library. Figure out what you have to use and plug off the rest.
If your motor is running really rough and adjusting the timing isn't helping,
it's probably a vacuum leak.
That's my brain dump for now. If I remember anything else, I'll do a follow
up message. If you have any ?'s, just let me know.
Original Edition: Shannon Shirk Sep 6 2002