Installing a 5.0/5.8L EFI Engine
All of the Early Ford Bronco's on the road are at
least 20 years old. Many of them driven by motors
equally old and with 150,000+ miles. While rebuilding these
older motors is certainly an option, a popular alternative
is to install a late model, Electronic Fuel Injected
motor. These motors are relatively cheap and with modern
electronics are incredibly reliable. This guide will help
you to install a late model EFI motor into an older truck,
with an emphasis on installation in an Early Ford Bronco.
In an Older Truck
- Engine Removal
- Power Steering
- EEC Installation
- Fuel System
- Fuel Pumps
- Selector Switch
- Relay Wiring
- Throttle Pedal/Cable
- Issue Summary
- 5.8L Notes
- Related Technical References
You will need virtually every piece of the doner EFI
engine. It's much better to find a doner car and go there
yourself to get all the little pieces. We have included a
parts list for you to use as
a guide. Basically, get everything that is attached to the
wiring harness. While you may not be able to get
everything on the parts list, try to get as much as you
Make sure you have all the parts and any tools you will
need close at hand before you begin. You could also
consider purchasing a complete crate motor from Ford or
Summitt Racing. Summitt had them for $2495.00 not so long
We recommend replacing any small bolt, hoses, etc. with
new, high grade hardware at this time. There isn't much
point in installing a highly realiable motor, only to bust
a radiator hose that's 10 years old. Spend the time/money
now, and save even more down the road.
The older, carburated motors were pretty simple. At this
stage we simply want to prepare the car to accept the new
EFI engine. Therefore:
This would also be a good time to replace your motor mounts,
especially if they are original.
- Remove the old Bronco engine, but do not
remove any of the wiring at this time.
- Remove the linkage from where the firewall and the throttle pedal
from inside the vehicle.
If you have bought a complete EFI motor, including the
engine's water pump, alternator, power steering pump and
air pump (if you have one), then you can used them all as
well as the serpentine belt. In most instances, the modern
parts are far superior to the originals. Even the air
conditioning compressor (or air compressor) will fit
without any extra effort.
Note: You will need an air pump on the engine
if it orginally had one in order to meet emissions
The 5.0L engine will fit with slight modification to the
hood braces, small dimples on front and rear braces to
clear the EGR fitting and A/C comp. The firewall may need
very small dimples at the air injection pipe (usually not
necessary if you install engine with motor mounts attached
then put them on afterwards). The 5.8L motor will fit if
you use Mustang shorty headers, change the upper intake
manifold (or use a hood scoop) and modify the smog tubes
at the back of the heads. You will also need to remove the
fan clutch. That's about the extent of the clearance
problems you will encounter.
If you decide to use the Bronco parts, put both engines
next to one another and remove the EFI engines alternator,
air pump and bracket. Remove the A/C, power steering pump
and bracket, and the water pump. the install the Bronco
water pump, alternator, air pump, power steering pump and
put it on the EFI engine.
Power Steering Hoses
If you are using the EFI accessories then either take the
ends off of the late model hose and your hose in order to
get a new custom hose made up at any hydraulic shop. You
could also get an AN adapter from one of the parts
houses. (Lee Manufacturing, Sun Valley, CA makes these,
there are others.)
You may also want to consider a new flow control valve to
better match a truck power steering box as opposed to the
doner vehicle's (this might be the case when using a 5.0L
out of a Mustang). These flow control valves are exactly
the same on the pump end, but is different on the hose
end. Also needed will be a seat for the valve adapters and
two fitting adapters, one for the valve and one for the
seat and the other for the hose and power steering
box. The cost is about $25 for the valve and adapters and
$30 for the hose.
Those of you installing an EFI into an Early Bronco with
the popular 2WD Pickup
Power Steering Conversion may have a problem with the
power steering pump pulley not clearing the box. This will
only be true for certain setups with A/C. A EFI motor
without A/C will have different brackets (available from
Ford, $69) which does not have this clearence problem. By
grinding of the front of the PS/AC bracket and two very
simple custom brackets you can get a bolt on setup. A
longer belt than stock will be neccessary (a 6-groove 915
A reverse rotation flex fan is required and many people
use the Flex-a-lite 1517. With this fan no radiator
modifications are required. To use the larger 1518
requires a 1.75" spacer and moving the radiator
forward. It is reported that the Hayden 3528 is the same
size as the Flex-a-lite 1517.
Depending on the fan you use, you may need to modify the
radiator and it's mounting. Most 4-row core radiators are
too large and come too close to the fan blades. The
radiator modification requires moving the top radiator
host inlet from the right to the left side, and the bottom
radiator outlet from left to right. (The 5.0 water pump
exits out the driver's side instead of the passenger
side.) Many people build custom hoses, but the procedure
described above is easily done by a radiator shop for
usually under $50, and very clean.
If you decide to use your old Bronco accessories, then put
both engines next to one another and remove the EFI
engines alternator, air pump and brackets. Remove the A/C,
power steering pump and bracket and the water
pump. Install the Bronco water pump, alternator, air pump
power steering pump on the EFI engine.
Wiring the EFI motor is straightforward. Simply take the
time to layout all the components, and make sure you
consult your wiring diagram.
You will need a wiring diagram for your Bronco. Each year
is a little different. It makes the wiring much simpler if
you get the wiring harness from the same year and model
car that you got the engine. You will also need the 5.0L
wiring harness for the year of your engine. This is
essential! If you don't get the wiring you must get
a wiring diagram for the year of car you got the engine
- In the engine compartment, mount the canister purge
solenoid. (Note that you may pick your own location.) A good
place is on the passenger side of the firewall. Mount the
Thermactor Air Converter (TAD) solenoid and Thermactor Air
Bypass (TAB) solenoid. Mount these units as close to the
canister purge solenoid as possible.
- Put in the EFI wiring harness in the Bronco and route
across the fire wall and wheel wells.
- You can pick your own location, but to keep the
electronics out of the engine compartment heat, it is
recommended that you install the computer unit under the
dash, on top of the heater. to do this remove the glove
box, drill a hole between the top of the heater and the
bottom of the dash into the engine compartment.
- From the engine compartment, make an oval hole 2-1/2"
by 1-1/2" for the rubber plug and wiring.
- Put the EEC control wiring plug and the EEC power
relay through the hole and install the rubber plug (which
should already be on the harness).
- Mount the EEC control unit to the left of hole as far
as possible to make clearance for the glove box for fuse
- Plug in the EEC control unit to the wiring plug.
Wiring the EFI alternator
If you use the alternator from the EFI motor you will need
to wire the alternator into the Bronco system. First
remove the voltage regulator from the Bronco. Do not
remove the wiring at this time. From the EFI engine
you will need the fusible links. the fusible links are on
the starter solenoid, there are about 4 of them.
Hook the wires up as follows:
- Black w/orange wire goes to the black w/red on the Bronco.
- Yellow w/white wire goes to the green fusible link on the starter solenoid.
- Light green w/red goes to the Amp gauge on the dash.
- Grey w/yellow wire from the heated exhaust gas oxygen sensor goes to the
run position of the ignition switch.
- Mount the coil on the left fender well and attach the red w/light green wire
from the coil to the start side of the ignition switch.
- The following wires are also in the harness, but their use is optional:
- Clutch cycling pressure switch.
- Air change temp sensor.
- Neutral sensing switch.
- Air Conditioning wide open throttle relay.
- The following two are variable. Some 1988 engines with the Mass Air Sensor seem
to require them, but not other engines.
- Engine coolant temp sensor.
- Air change temp sensor.
All red wires to the run and start side of the ignition
switch. In the wiring harness there is a group of red
wires tied to one common red wire that goes to the
Now that you have all of the engine accessories and wiring
harness installed, it's time to bolt up the
transmission. Using a hoist, manuever the engine into the
engine bay. Early Bronco's came with both standard and
manual transmissions, and each has a slightly different
set of requirements.
A custom speedometer cable is needed to fit the stock
Bronco speedo head and the vehicle speed sensor (VSS)
found on the EFI motors ($25). The VSS plugs into the
transfer case. Take the gear off your old cable and put it
on the VSS and fabricate a simple holding bracket.
If you use an automatic transmission then you will
probably be able to use the exhaust headers from the doner
engine. Mustang headers are known to work. (The clutch
linkage of the manual gets in the way.) You may find a
small interference fit between two of the hood braces and
the EGR valve/air conditioning service valve. A hammer
will fix this. Install the space plate and then the flex
There is also a compatibility problem with flywheels. The
older engines have an 28.2 oz-inch imbalance, while the
newer '85 (maybe '83) and newer motors have a 50 oz-inch
imbalance. You must either obtain a new flex plate or have
your old one rebalanced.
If the engine comes with a flywheel, check and see if it
is the larger 164 tooth flywheel for an 11" long style
clutch. You can reuse the old flywheel if you get it
rebalanced. The new engine probably doesn't have a boss
for the bellcrank bracket. You have two choices:
This is difficult to explain in words, but obviously
you don't want to drill in the wrong place. Make sure
you get this right!
- Create a
custom bellcrank bracket. You could also use a custom
hydraulic or Morris cable setup. Or
- Mount the
space plate and bell housing to the EFI engine, then bolt
the clutch bell crank pivoting bracket to the bell
housing. Compare with your old block, and mark the 5.0L
engine block where the second bolt must go. Drill and tap
for a 1/2" bolt.
Now install the fly wheel, spacer plate and pressure
plate. Then install the bell housing.
Fuel systems have progressed over the years just as the electrical systems have.
Review this for accuracy
Ford has used several different fuel systems over the
years. The early '84-'86 Mustangs used a externally
mounted high pressure fuel pump as well as the '83-'87 F
series pickups. For the first year of these pumps they
were used alone. Later, a low-pressure "pusher" pump was
added. The current system uses an in-tank high pressure
pump, so if the doner is a later model you will need to
obtain at least a high pressure fuel pump.
High Pressure Pump
Here are some part numbers for high pressure fuel
pumps. If used alone these pumps should probably be
mounted as close to the tank as possible. There are a
number of people reporting success using these pumps after
the selector valve, toward the engine. A good location is
on the outside of the right frame rail, under the
High Pressure Fuel Pumps
|Ford ||E4ZZ 9350B
|Federal Mogal ||P74-028
|Holley 512-101 ||512-101
Low Pressure ("Pusher") Pump
A low pressure "pusher" pump will ensure that your high
pressure pump is well fed. They are usually rated at 5-7
psi. The Federal Mogal P4594 pump (same as the AC Delco
EP247) is a rotary-vane style pump rated at 7psi and
72gph. It's not great at pulling fuel from the tanks, but
if located close to the rear main tank should work fine.
Fuel Selector Valves
If you have dual tanks you will need a 6-port electric
solniod valve to switch supply and return lines from each
tank. A company, Pollak, makes such a valve, part #42-159
for the selector and 42-203 for the electrical
connector. Although the valve is all plastic, we have had
no reports of problems. The valve has 3/8" tube fittings
for the supplies, and 5/16" tube fittings for the
return. Pollak also makes a marine unit, part #42-159S,
which is of stainless construction. Pollak can be reached
at (617) 282-9550. They run about $40. NAPA also makes a
valve that looks similar.
Fuel Relay Wiring
If using the Ford fuel pump (E4ZZ 9350B) you may hook up
the fuel relay pump as follows: The fuel pump relay is
mounted next to the EEC control unit under the dash. From
the relay the pink w/black wire goes to the fuel pump on
the power side. the black wire from the fuel pump goes to
ground. The orange w/light blue wire goes to the brown
fusible kink. the red w/black goes to the inertia
switch. From the inertia switch, the red wire goes to the
red group of wires. You can mount the inertia switch at a
location thaty is to your liking. The tan w/light green
goes to pin 22 on the EEC control unit and the EEC IV SELF
TEST CONNECTOR. The fuel pump relay is located under the
driver seat in the Mustang. You will need this and the
inertia switch from the trunk.
On the Bronco's accelerator pedal linkage rod, drill out
the ball end on the rod, where the linkage through the
fire wall connects, to the same size as the Mustang
throttle cable. Now heat the shaft below the hole you
drilled (at the dog leg) and turn it 90 degrees. Cut a "V"
notch the same size as the cable so the cable will fit in
the hole that you drilled. Now mount the mustang throttle
cable to throttle peddle mounting bracket, squeeze the "V"
notch together. Use the screws that were used to hold the
rubber boot on the Mustang to mount metal plate and
throttle cable to the accelerator pedal brakcet. Put the
cable through the hole in the fire wall and route the
cable behind the engine to the left side and put the cable
on the throttle body.
You will need to install Oxygen sensor bosses in the
exhaust. A good exhaust shop should have the bosses
available and be able to install. On some systems the O2
sensors can tell which cylinder in that bank is running
rich/lean. You should try to locate these sensors as close
as possible to the stock position.
The situation of a transplanted engine in California is
unclear, even to those people who live there. The best
advice for someone in that state is to discuss your plans
with the shop who will be performing the smog
check. Note: If you bring in your vehicle from out
of state, do NOT tell that you drove it into the
state. This will save you about $100. (They will give you
a wavier to drive it to the smog shop.) As far as is
known, if you bring in a car from out of state and it
passes emmissions for that year you are legal.
There are some who claim that a car/truck can pass only if
the engine is one of those the model was originally
produced with. Thus, a Bronco with a 302 could not be
upgraded to a 351W, but a 200ci I6 could be upgraded to a
302. In the case of two very similar motors such
as the 302/351W, it is likely that putting your original
302 smog equipment on a 351 will pass you as a 302. Of
course with the EFI you are passing emissions for the year
of the engine.
Others claim that their 302->351 Bronco's have
legally passed emissions. It must be taken to a referee
station, where it will be inspected and a new smog
identification plate added to the door frame to identify
the swap and the type of equipment that should be on the
vehicle. Again, the best thing is to check with your local
An interesting note for owners in California who have
manual transmissions (at least on the early models). It
seems that the thermactor air injection system is not
needed for an automatic transmission. Therefore if you
swap in an automatic you can pass smog without the TAI
system. Again, check with your local emissions office.
Still others state that the emissions must only meet the
newer, of either the vehicle or engine. This means that
you must use the entire original exhaust system:
pipes, catalytic converter, muffler, and all engine
mounted smog accessories. (This might not be neccessary if
you use an older block with the newer fuel
system. California has recently proposed additional
emission regulation. You can read a review of the new EPA Smog Check
Check the radiator, power steering and other fluids and
turn the ignition to the on position. Check for fuel leaks
with each tank on line. You will have to pressurize the
fuel injectors the first time. After the motor starts
check for oil pressure. It should be around 45 psi at
idle. Observe the temperature gauge (you did take this
opportunity to install an accurate set of guages, didn't
you?) and allow the motor to idle until the temperature
- You must either obtain a new flex plate or have your old one rebalanced.
- Fuel Pump
- Your ols mechanical fuel pump will not adequately supply an EFI. You will need an electric fuel pump.
- Clutch Bracket
- The EFI motors do not have a mounting hole for the clutch linkage.
- HEGO location
- You will have to add O2 sensors to your exhaust system.
- The 5.0 water pump exits out the driver's side instead of the passenger side.
You will need to modify the radiator or make up some costom hoses.
- Power Steering
- You will need to install new ends on the power steering hoses.
- Speedometer Cable
- A custom speedo cable is needed for the vehicle speed sensor (VSS)
There are a few considerations when installing the 5.8L
motor. As mentioned in the accessories section, the 5.8L
motor will fit if you use Mustang shorty headers, change
the upper intake manifold (or use a hood scoop) and modify
the smog tubes at the back of the heads. You will also
need to remove the fan clutch. That's about the extent of
the clearance problems you will encounter. You will also
need an oil pan to fit in the Bronco.
|E8FZ 12A664 A ||Bar Pressure Sensor
|E8ZZ 12A690 A ||O2 Sensor Pig Tail
|F03Z 9F472 A ||O2 Sensor
|E6AZ 9B989 C ||Throttle Pos. Sensor
|E6DZ 11433 A ||Relay Assembly
|E8ZZ 12A650 DB ||Computer
|E6PZ 12286 V ||Coil Wire
|E4ZZ 9350 B ||Fuel Pump.
|E6ZZ 9A750 A ||Throttle Cable
|E8SZ 6750 A ||Dip Stick
|E6LY 18472 C ||Heater Hose
|E7SZ 18472 A ||Heater hose
|E5ZZ 3C11 A ||Support P/S Pump
Related Technical References