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.

 

 

METHOD 1: Rear Cylinders

 

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.


METHOD 2: Forward Cylinders

 

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.