1976 280Z FUEL INJECTOR HOSE REPLACEMENT
Examination
of the fuel injector hoses showed they were of different types and one was
cracked enough to be scary, and one hose was oozing gasoline where it connected
to the fuel rail. It was motivation enough to change them all. The fuel rail
on a 1976 280Z is in two pieces connected by rubber hose that connects each
section to the fuel pressure regulator toward the bottom and the fuel supply
"T" at the top. This configuration, although it may not look as
"clean" as a one piece fuel rail, allows 3 injector hoses to be
changed at a time. A much more manageable task, in my opinion than trying
to change all six at once. I used two methods to replace each half, the second
method derived from things I learned from the first.
q Method 1: Remove rail. Remove injector
and fit a new fuel hose to each injector individually.
Remount and secure each injector and finally remount fuel rail mating three
hoses to three fuel pipes.
q Method 2: Remove rail. Remove injectors and fit a new fuel hose to each injector.
Attach the injectors to the fuel rail fuel pipes. Remount whole assembly.
Tools and supplies:
Not
everything on this list may be needed and you may need other tools to
facilitate the job. I had all these things on hand and used them. Sometime I
used them for the purpose they were desined for, sometimes more creatively.
q Phillips screwdrivers,big
and small for injector mounting and various screws.
q Blade screw driver with long
reach for tightening hose clamps.
q Handicut or something very
sharp to cut hoses. Sears Handicut has a razor blade with plier like handles.
It has a razor on one side and a plastic anvil opposite. This tool is good
because it provides the razor function but because of the handle and the anvil,
it is less “dangerous” than a razor blade.
q Socket set.
q Channel-lock type pliers
q Needlenose pliers – handy
for retrieving things that drop on the manifold.
q Large wire cutters
q 1/4 inch fuel injection hose
for connecting fuel injector to fuel rail (about 2 feet to allow for errors
that ruin hose)
q 12 Fuel injector hose clamps
to fit the 1/4"hose. Fuel injector hose clamps have a solid band and an
external screw rather than the slotted hose clamps with an internal screw that
are for low pressure uses.
q 5/16 inch fuel injection
hose for connecting fuel rail to fuel pressure regulator, fuel supply
"T" (about 1 foot should handle the four connections)
q 4 Fuel injector hose clamps
to fit the 5/16" hose. Fuel injector hose clamps have a solid band and an
external screw rather than the slotted hose clamps with an internal screw that
are for low pressure uses.
q WD-40 for lubricating inside
of new hose and metal connections to make them easier to assemble.
q Duct tape – for anything
q Utility wire – help hold
wires and tubes out of the way while you are working.
PREPARATION FOR BOTH METHODS
To
limit any collateral damage should the unthinkable and improbable happen and
you have a fire, the car should be outside (I did this at home and thoughts of
the house burning down danced in my head like sugarplums) Let engine cool.
Overnight is very good. Remove the battery terminal. (You will be working with
gasoline. Remember?)
Put
rag under injector area and have a roll of paper towels at hand to soak up
gasoline when the hoses a cut free from the fuel rail. Also 1/2 paper towel is
a good thing to use to cover an exposed injector mounting hole to keep stuff
out.
I
replaced the rear three injector hoses first because they were easier to get
to. I used method one. I pre-cut 6 lengths of hose to 1.5 inches (Duh. I ended
up using 1 or 2 of this length. At about $4 a foot for the fuel injection hose,
pre-cutting was a mistake!). To start I unplugged the injector wires noting
which goes where. After removing the injector wire and any other wires from the
wire holder that is part of the fuel rail, I moved the injector wires aside. I
unscrewed the fuel rail mount. I cut the hose between the fuel rail and the
fuel pressure regulator and then the fuel supply "T". I used a
Handicut. Have paper towels handy. This is where any pressure left in the system
will force gasoline out and it will take a couple of paper towels to soak it
up. The first cut yields the most fuel because of the pressure. The other cuts
still yield fuel but it drips out. Cut the hoses between the fuel rail and each
of the injectors. The fuel rail can now be removed. Leave the old hose
fragments on or note where they were for future hose length measurement. Once
the fuel rail is removed (take a break and clean up the fuel rail a bit. If it
is bent, gently straighten it), I removed each of three injectors that were
attached to the rear portion of the fuel rail. For each in turn I did the
following:
Unscrewed
the injector and removed. Covered injector port with part of a paper towel.
Removed the old hose from the injector by cutting lengthwise (being careful
not to scar the metal underneath). If the injector hose had a collar at the
injector end that eliminated the need for a clamp, once the hose is removed
it should come off easily. Some of the injectors had them and some did not,
so I took them all off. Put the fragment of hose from the injector together
with the fragment of old hose from the fuel rail and estimate the length of
hose needed and cut it at least 1/2" longer than needed. You can trim
it later. Make sure ends of hose are cut square. Lubricate the new hose inside
with WD-40 and put the hose on the injector as far as possible. I found I
could force the hose all the way to the base of the hose connection on the
injector by finding a socket from the socket set that just fit over the end
of the hose. Then placing the socket-hose-injector against something (I used
a riser on the front stairs, 2nd from the bottom), holding the
injector firmly and leaning my weight against it the hose can be forced down
all the way. A hose clamp is then placed on the injector. Some care is necessary
to position the clamp so that it does not interfere with the injector mounting
screws. I found that having the head of the clamp screw about 40 degrees from
the injector wire connector on the other side of the top mounting screw puts
it in just about the right place. Tighten the clamp. The unconnected end of
the fuel injector hose should be prepared for connection to the fuel rail
pipe by flexing and stretching (enlarging) it a little bit with some object
about 1/4" or slightly bigger. The connection process will be a bit easier
if this is done. The injector is replaced in its mounting hole and screwed
in snugly. Make sure the injector wire connector at the top, slightly to one
side of the mounting screw. Put the second hose clamp on the injector hose now. Orient the
screw head so that it can be tightened when everything is assembled. Do this
for each of the three injectors.
Measure
and cut the 5/16" hose to connect the fuel rail to the fuel pressure and
fuel supply pipes. Put the hose on the fuel rail, put on and tighten the hose
clamp. Put on second hose clamp but do not tighten. Orient the screw head so
that it can be tightened when everything is assembled. Now the fun begins. The
fuel rail must connect with three injector hoses and the fuel pressure
regulator and the fuel supply "T". Put the fuel rail in the general
place it will be when connected and using your judgment, trim any injector fuel
hose that needs it. Proceed with assembly. Once the hoses are all aligned they
must be pushed on far enough for a clamp to fit between the fuel rail tube
flair and the end of the hose with about a millimeter of hose protruding beyond
the clamp. It is very hard to describe how difficult this is. The five hoses
are pointing each their own way. If your lucky you will be able to insert them
in an orderly fashion but for me one would align and another one which had been
aligned would pop off and point the wrong direction. The fuel rail supply tubes
and the injectors generally align.
The stickler is that is true only after the connections to the fuel pressure
regulator and fuel supply "T" are made and pushed into position. Once
the three fuel injection hoses are somewhat connected to the fuel rail gently
but firmly press the hose onto the fuel rail tube. The flair near the end of
the tube needs to be pushed on far enough for a clamp to fit between the tube
flair and the end of the hose with about a millimeter of hose protruding beyond
the clamp. This takes a lot of pushing, all the while avoiding any possibility
of breaking a $50 injector. Ugh. When the three injector hoses are attached and
the fuel rail to fuel pressure regulator and fuel rail to fuel supply
"T" is made to your satisfaction the fuel rail mounting bracket hole
should be close to the threaded hole for its bolt in the intake manifold. If
not, put on gloves to protect your knuckles and gently but firmly align the
holes and put the bolt in place and tighten it. You may need to adjust the
distance the fuel injector hose is pressed on to the fuel rail to facilitate
this alignment. Once the fuel rail has been secured with its mounting bracket,
tighten all loose hose clamps. Make sure everything is tight. Wipe off all hose
connections so you can easily see if they leak (some did for me the first
time). Reconnect injector wires. Reconnect battery. Leave the hood up. With a
fire extinguisher handy (its high pressure gasoline, remember?) start the car
(don't worry if it doesn't start like normal. Takes a few turns for the fuel
rail to pressurize and the WD-40 to dissipate. Let it run for a couple of
minutes. Turn the off engine and check for fuel leaks. If there is one tighten
that clamp, clean off the gas and start the engine again. Check again for any
leaks. If there is still a leak, sit down and take a deep breath. The leaky
hose may not be long enough to allow the clamp to make a tight seal or you may
have used a clamp that is too large for the hose. When I thought I was all done
I had to replace a hose that was about 1/2 an inch too short. Remember- gloves
to protect the knuckles and plenty of gentle but firm shoving should allow the
change without complete disassembly. But do what you must to make it right. If
you lack motivation imagine, an engine fire consuming all your hard work. The
above tasks took a good 8 hours and pooped me out. It took a lot longer than
necessary because I did not know anything about what I was doing and I wanted
to do everything right. I waited a day to do the front three injectors.
I
replaced the front three injector hoses second using all the tricks and
learning from all the mistakes I made from the rear three injectors. Since the engine
was run again the fuel rail was pressurized again. To start the process, I
disconnected the battery. I unplugged the injector wires noting which goes
where. There might be vacuum lines or other wires in the way. Disconnect and
move everything out of the way as necessary. I unscrewed the front fuel rail
from its mount (the screw on this one was missing so I did not have to unscrew
it). I cut the hose between the fuel rail and the fuel pressure regulator and between
the fuel rail and the fuel supply "T". Have paper towels handy. This is where any
pressure left in the system will force gasoline out and it will take a couple
of paper towels to soak it up. The first cut yields the most fuel because the fuel
in the fuel rail is under pressure. The other cuts still yield fuel but it
drips out. Cut the hoses between the fuel rail and each of the injectors. The
fuel rail can now be removed. Once the fuel rail is removed (take a break and
clean up the fuel rail a bit. If it is bent, gently straighten it.), I removed
each of three injectors that were attached to the front portion of the fuel
rail. Measure and cut the 5/16" hose to connect the fuel rail to the fuel pressure and fuel supply “T” pipes. Put
the 5/16" hose on the fuel rail, put on and tighten the hose clamps. Put
on second hose clamp but do not tighten. Orient the screw head so that it can
be tightened when everything is assembled.
For
each injector in turn I did the following:
Unscrewed
the injector and removed from the engine injector port. Covered the injector
port with part of a paper towel. Removed the old hose from the injector by
cutting lengthwise (being careful not to scar the metal underneath). If the
injector hose had a collar at the injector end that eliminated the need for
a clamp, once the hose is removed it should come off easily. Some of the injectors
had them and some did not, so I took them all off.
Put the fragment of old hose from the injector together with the fragment
of old hose from the fuel rail and estimate the length of hose needed and
cut it. A pretty much exact measurement and cut can be made. If a hose appeared
too short you can cut it a bit longer. Injectors that had a collar at one
end of the hose should be cut 1/8” longer. Make sure all new fuel lines
have clean, square cut ends. Lubricate the new hose inside with WD-40 and
put the hose on the injector as far as possible. I found I could force the
hose all the way to the base of the hose connection on the injector by finding
a socket from a socket set that just fit over the end of the hose. Then placing
the socket-hose-injector against something (I used a riser on the front stairs,
2nd from the bottom), holding the injector firmly and leaning my
weight against it the hose can be forced down all the way. A hose clamp is
then placed on the injector. Some care is necessary to position the clamp
so that it does not interfere with the injector mounting screws. I found that
having the head of the clamp screw about 40 degrees from the injector wire
connector on the other side of the top mounting screw puts it in just about
the right place. Tighten the clamp. The unconnected end of the fuel injector
hose should be prepared for connecting to the fuel rail pipe by flexing and
stretching (enlarging) it a little bit with some object about 1/4" or
bigger. The connecting process will be a bit easier if this is done. Put the
top hose clamp on the injector hose now, paying attention to the ultimate
position will be. Press the injector hose onto the fuel rail pipe. Note that
it is much easier to get a good fit between the injector hose and the fuel
rail using this method than method 1. Do not tighten the hose clamp on the
fuel rail yet. Make snug. Orient the screw head so that it can be tightened
when everything is assembled. Do this for each of the three injectors.
The injector mounting parts have a tendency to
fall apart. By fabricating 6 plastic or cardboard "keepers" that
fit on the injector mounting screws and can be removed later, the whole assembly
can be held together. This is the secret of method 2. Without the "keepers"
there is only frustration ahead as things fall apart and have to be dug out
of the web of manifold pipes.
Assemble
all the mounting pieces of the injectors and then insert the mounting screws
through them and put the “keepers” on to hold the whole assembly
together. 
The
injector is replaced in its mounting hole, the screws are started in the threaded
holes. They should screw in smoothly. Some gentle but firm alignment is necessary
to align all of the parts. If the injector
mounting screws do not turn smoothly, you risk cross-threading the threads in the intake manifold. Back out
the screws, realign the injectors and try again. When the screws are properly
started, remove the “keepers”. Make sure the injector wire connector
is at the top, slightly to one side of the mounting screw and screw the injectors
in snugly. Using gentle but firm pressure (wear gloves to
prevent scraping knuckles or skin) on the whole fuel rail align the fuel rail
to pressure regulator hose and the fuel rail to fuel supply “T”
hose and connect them. Tighten all hose clamps holding them with gloved fingers or gently with pliers as necessary
to keep them from rotating. Fasten fuel rail to support bracket. Dry all hose
connections to make it easy to detect leaks. Connect injection wires and reconnect
any thing else disconnected to clear the work area. Reconnect the battery.
With a fire extinguisher at hand, start the engine. Don’t be surprised
if it does not start right away. The fuel rail is empty and needs to be re-pressurized
and there is a trace of WD-40 in the hoses as well. Let the engine run for
a couple of minutes. Turn off the engine and check for leaks. If none (there
we none for me this time) tighten the fuel hose clamps one last time. Reroute
all wires and hoses where they were before you started. Tighten the battery
terminal.
Close
the hood clean up your tools. You are done! Not only did you replace your fuel
injection hoses but you got real intimate with what is what under your hood.
Using method 2, this process took about three hours. It seemed more “in control”
than method 1 and connections of the fuel injector hoses to the fuel rail tubes
is easier to achieve.