| Parts List
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Howell TBI Fuel
Injection kit. |
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A 9" to
11" Air Filter Assembly and Air Filter |
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Small, round
indicator lamp (Radio Shack) |
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| INTRODUCTION: Now that I've ramped up my off-roading to
a new level, I quickly faced the music that my Weber carburetor
(like all carbs) leaves me hanging on steep inclines and puts me in
situations I'd rather have the motor running! I also spent a
good amount of money and time last year squeaking through emissions
inspection. I felt it was time to insert some modern
technology into this 20 year old CJ. I bought a Howell
TBI fuel injection kit (the California Emissions version) and began
my next project! |
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| The very first
step is to take the negative battery cable off the battery.
Then remove the manual fuel pump from the passenger side of the
motor. It's right next to the distributor. Toss this on
the floor to start building what will soon become a snake pit of
crap you can throw out. Howell gives you a small plate
and gasket to cover this hole. Toss
the fuel hose, filter, and hard fuel line going from the old fuel
pump to the carb. |
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| The
next thing is to pull off all of the factory emissions equipment
off. You can pull every vacuum hose in the jeep if you want
because the Howell kit only needs about half a dozen to
function.
I was running a Weber carb and had a
lot of the Carter BBD emissions equipment removed already, but for
your notes, remove the following:
| 1) Remove the
whole air cleaner system or THERMAC. |
| 2) When you pull
the vent line from the carb to the canister on the driver's
side, plug the canister port as shown in the 2nd picture on
the right. |
| 3) Disconnect the
electric choke wire (red) |
| 4) Take off the
throttle return spring because the TBI unit doesn't need it. |
| 5) Remove the Decel
valve |
| 6) Pull all the
hoses from the CTO
valve, but leave the valve where it is. |
| 7) Remove the WOT
(Wide Open Throttle) switch. |
| 8) Remove the Vacuum
reservoir from underneath the battery tray. |
| 9) Remove the 4"
and 10 hg switches that are attached to the firewall above
the valve cover. |
| 10) Unplug the
knock sensor. This switch is on top of the intake
manifold right in the middle of it. I left the
switch in the manifold and just unhooked it. |
| 11) Unplug the stepper
motor. |
| 12) Remove the 3
vacuum solenoids. |
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| Pull the
pulse air tubes out along with the emissions equipment in the
previous step. This includes the two check
valves, the big pulse air tubes and the air
valve. The picture to the right shows one of the two
places you'll need to weld shut. There's a nipple on the
catalytic converter and one on the exhaust pipe. Take pliers
and flatten them (crimp) and then weld the seam shut. |
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| Remove
the old carburetor and clean up any gasket residue on the surface of
the throttle intake. Stuff a rag in the intake so nothing
falls into it. You should also remove the 4 studs that
held the carb onto the intake.
When you're finished up to this
point, you'll have a nice snake pit of junk forming on your garage
floor. |
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| Now
it's time to assemble the new electric fuel pump (pic #1).
You're going to need to use a small tube cutter to cut the passenger
side fuel rail so you can position the pump above the transfer case
skid plate (pic #2). Some people flair the end of the fuel
lines, but I didn't.
You can attach it using the clamp
that comes with the kit and use one of the holes in the frame rail
that held the old hard fuel line on. Cut the fuel line
and be ready to plug the line or you'll get soaked with gas!
Use the little red caps that come with the fuel pump to plug the
line.
The 3rd pic on the right shows the
new fuel hose going from the pump to a piece of the old hard line
that use to go to the manual fuel pump. Note, the other
red and blue hose above it is for my on-board-air system and ARB
locker.
The last picture is the new fuel
filter connecting to the hard line going to the gas tank.
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| Now
the TBI unit can be placed on to the intake manifold.
Place the supplied gasket that looks like the exact shape of the 2
barrel intake on to the intake. Then place the adapter plate
in the kit on top of that and secure it with the 4 Allen
bolts. Tighten in a criss-cross pattern to get a proper
seal.
Place the adapter gasket on
top. Older Howell kits had some very poorly cut gaskets
that forced you to use silicone to get a better seal. I was
pleased to see that they fixed this.
Place the TBI unit on top of that
gasket and secure tightly with the 3 supplied bolts. Hook up
the vertical throttle bar from your old carb to the TBI unit.
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Replace the coolant temperature
switch in the intake manifold with the new one supplied in the
kit. I think I used a very large 3/4" wrench to get this
out.
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| Reconnect
the vacuum lines. The kit comes with a diagram, but maybe this
will save you some time.
1) Run PCV to a "T" union,
send one end to the large opening on the front of of the TBI and the
other down to the purge canister.
2) The port under the PCV port on the
TBI needs to be "T" union-ed as well from the EGR valve to
the CTO valve and then across the motor to the distributor.
3) The remaining port on the CTO goes
to the purge canister.
4) The two open ports on the left and
right of the TBI can be plugged.
5) You can run your CCV line from the
back of the valve cover to either the bottom or top of your air
cleaner assembly. You will most likely need to drill a hole
for this and secure it with a plastic threaded elbow.
6) There is a port on the back of the
TBI that goes to the MAP Sensor hanging upside down on the wiring
harness. (see pic) |
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| Replace
the old oxygen sensor with the new one in the kit. If your
exhaust pipe or exhaust manifold has not sensor in it, Howell
provides a threaded bunge to place in the exhaust down pipe.
You would need to remove the down pipe, cut a hole and weld the
bunge in place. |
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| The kit also comes with a Speed sensor that screws into the hole in the transfer case that your speedometer cable goes in. Put it
there and then screw the speedo cable into the new switch.
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| You
need to pull your glove box out to install the new ECM
computer. When the glove box is removed, unscrew the one screw
in the retaining bracket that holds the stock computer in
place. Extract the old computer and remove it from the
harness. There's one bolt on the back that holds the wires
in. Toss the old computer in your pile of junk.
Remove the rubber grommet on the
firewall that holds the wiring harness to the computer.
You have to take a cut-off wheel and slice into the middle of this
grommet to extract the wires. Push the old harness
through into the engine bay and leave it there for now.
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| Find
and extract the orange and purple wires (they are twisted together) that go from the distributor within the
old wiring harness. You can trace these two wires
through the harness (yes, cut the electrical tape, wire ties, etc)
all the way over to the ignition module which is the square metal
object under your coolant overflow bottle. Remove the
coolant bottle temporarily so you can get to this easier.
There are two plugs on the ignition
module. One has 4 wires in it. It plugs into the old harness
where there is a black, green, purple and orange wire. You
want the purple, orange and black wires from the ignition module to
go across the engine bay and connect to the distributor's connector
with the same colored wires. You
want the green wire to cross over to the coil. In
essence you just did a "Nutter Bypass" as you have just
bypassed the part of the harness going to the old stock computer
that controlled your spark timing. Take
out all of the old wiring that started from the old computer and
toss it out. You'll also need to throw out the older
diagnostic connectors on the left side of the battery.
You now have your final piece to toss into your garbage collection.
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| Take the
Howell wiring harness and hook up everything to you TBI unit and all
of the new switches, fuel pump, etc. Each connector is
marked where it should go. You can mount the two relays and
fuel pump fuse to the firewall to give you an idea where the harness
should be positioned so that it reaches everything.
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| Now push
the blue connectors through the firewall and put the rubber firewall
grommet back in place. Connect the blue connectors to the new
computer in behind the glove box. It's a tight fit, but it
will all stuff up there nicely.
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| The diagnostic
connector and fuse panel can be secured with Velcro to the heater
duct.
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| The last
two things to do are mount the small indicator lamp in your dash and
connect it to the wires for the service check light and to find a
12v source of power for the entire system that is always on.
To make it easy, find the thick, red
ignition wire under your dash on the driver's side and splice the
wire from the Howell kit to it. Make sure you solder and tape
it up well.
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| Add an air
filter to the TBI and you're ready to go.
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| Starting
for the first time and other notes:
1) Turn the key to the on
position. The check light should come on and stay on and you
should hear the fuel pump engage.
2) Check for leaks in your fuel lines
at this point.
3) Crank the engine (do not pump gas)
to purge the air out of the new fuel lines. This may take a
few tries so don't get worried (like I did) :-)
4) If the motor isn't starting after
a few tries, then you may have used an incorrect 12v
source. The wire you choose must have 12v when the key
is on, when it's cranking, and when the key comes back to running
position.
5) If it's idling high, you may need
to adjust your throttle linkage so it's not pulling down slightly
and feeding it gas.
6) If your accelerator pedal is too
low to the floor, adjust your linkage to solve this as well.
7) The Howell kit comes with a bent
threaded bolt to use for your air cleaner. The air cleaner I
bought had a wing nut that needed to be drilled out and tapped to
fit the thread sizing of that bolt.
8) Recheck for fuel leaks. Make
sure the throttle isn't getting snagged by any hoses or wires.
Make sure you've tied all the wires down and secured them neatly.
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| Conclusion:
Wow! This thing idles great, it definitely has more pick-up
off the line. I love not having to pump the gas to get it to
cold-start and I look forward to not stalling on steep inclines
while off-roading. Seems as if I'm getting a
couple more miles to the gallon as well.
Questions or
comments please email me at :
jimadams68@comcast.net
Note: Some images are linked
from SierraJeep.com with
permission.
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