Fuel Injectors...replacement steps....

I replaced them on my gen 1 (which is pretty much the same 1NZ engine) without removing the valve cover. Take a look at this thread.

I have a set of 1NZ injectors here, restored by Rich Jensen, the last set that went through our PriusChat injector exchange some years ago. I would need to make sure the protective lube he puts in them hasn't become gummy as they've sat.

 

No no no no no no no oh my goodness no don't do that.

The ends that go in the fuel rail have O rings. Put those ends very carefully into the fuel rail first, lubing and twisting as needed.




The bottom ends that sit in the cylinder head sit in simple grommets. It's easy to get those ends in, as you install the rail with the injectors' O-ring ends already carefully inserted into it.

If you put the injectors in the cylinder head first and then try to get the fuel rail installed over them, you take a significant chance that the O-ring ends won't go into the rail right.

If you then try cranking down on the fuel rail bolts thinking "this'll make 'em go in", you will, if you are lucky, only destroy some O rings, and if you are less lucky, you will destroy some injectors.

 

Boy, “valve cover” and “cylinder head” terms are being used interchangeably.

hopefully even valve cover removal not needed: the repair manuals do err on the side of excessive, regarding removal for access.

 

They should go easily enough into the cylinder head holes ... no O rings on those ends, just flat grommets.

As your last step of inserting the injectors into the fuel rail was to verify you can easily twist them back and forth, if you find a little twisting eases them into the head grommets, there's no reason not to.

 

I just went through this, so here are some warnings first:
1) Unless you have done injectors before, you are not good at it, by definition. Get very humble in your soul, and then proceed.
2) You MUST bend, contort, lean, move so you can see the o-ring when you are inserting it into the fuel rail, even if you are left with oil in your ear and the impression of a coil on your forehead (well, slightly exaggerated). Visual feedback is critical to you sliding the o-ring in without damaging it. (I ruined seven o-rings before I learned how. That's how I know).
3) You MUST treat each o-ring as your most prized possession throughout this process. It will destroy itself very quickly if you do not. They are NOT robust, and it is NOT their fault when they tear. It is your fault, grasshopper.
4) This is more like brain surgery than mechanical work. Get rid of your macho and work very carefully and you will do fine, grasshopper, after you have ruined your fair share of o-rings in order to attain Patient Insight and Oneness with your Prius. (You think I'm joking, don't you?)

Now. My tips:
1) Change the grommets in the block first, and put a drop of oil to lubricate the circle in the middle before setting each one in place.
2) Put fresh clean petroleum-based axle grease on the o-ring on the fuel rail end of the injector, and put some on the dimple in the fuel rail where it goes as well. Not an excessive amount, just enough so they will always slide grease-on-grease on both surfaces. Don't cake it on--you don't want your fresh injector to get grease into its working parts, but use enough to slide grease-on-grease. When you insert your first injector into the fuel rail, you'll get a feel for how much grease is needed. (By the way, if worried about your grease, consider testing whether gasoline melts away your grease. It should.)
3) Bend over, and watch the o-ring, and very, very gently move the injector back and forth slowly until the o-ring slips into the rail. I did not twist mine. Press gently until the injector is fully seated in the fuel rail. It is possible to actually watch the o-ring for each injector as it slips into the fuel rail, although you may think you can't for Cylinder #4.
4) #4 is harder to insert, because clearance is minimal. I suggest you do the injectors left to right so you have three successes before tackling #4.
5) Now. You have inserted 4 injectors, and good for you. Slow down. You are not out of the woods yet. That part was hard. But the next step is too. Wipe a bit of oil on the engine on the end of each injector to help it pop into those grommets. Now slow down again. No speed, no macho here... Go on.
6) And carefully, and slowly, and without any care of finishing the job quickly, align the fuel rail and each injector into each grommet in the engine. Take lots of time here. If you don't you can punch a nice round hole in a grommet--don't ask how I know, just trust me, the engine end of the injectors are really effective sharp round punches. (If you do manage to punch a chunk of rubber out of the grommet, you can enjoy taking off the intake manifold to fish out the round piece of rubber that is now resting on your intake valve. Again, don't ask how I know.)
7) There are two plastic caps that ride on the engine beneath the 12mm bolt holes that hold the fuel rail on. They are spacers. They are not for crushing, or for forgetting. Align the rail carefully, making sure the rail and spacers and injectors and grommets are all aligned, and press the rail into place. If anything binds, pull back and figure out what is caught. The bolts are NOT for pressing injectors into the grommets. See #6 above. Tighten the bolts down.
8) All four injectors should be about 1/8 inch from the rail, and the same height. If so, install your electrical connectors.
9) Be prepared to shut off the engine quickly as you fire it up for the first time. Fuel spraying all over means that grasshopper must try again. It does pay to watch which fuel injector was spraying. Let fuel dry up before firing the engine the next time to avoid a fire. And it is definitely a no smoking area.
10) Check for raw fuel smell the next several times the engine fires. Raw fuel smell means a leak, and if you smell some, grasshopper, your job is to do the o-rings all over again!

 

Very good advice, thank you.

For my part, rather than being prepared to shut off the engine quickly, I put the car only IG-ON and run just the fuel pump for a leak test.

In gen 1 it was quite easy to run the fuel pump with a jumper wire at the fuse box. In later generations that's less practical, and it is easier to use a scan tool with a "run the fuel pump" test on the menu,

 

Thanks for the detailed instructions. I re-read this several times and tried to correct my fuel injectors installation with new O-rings few times already. No matter what I do, fuel keeps gushing out of #4 injector on right driver side. I am beginning to think that fuel rail somehow got damaged and it needs to be replaced. I took pictures of how all four are seated into the fuel rail. As you can see, no matter how many times I tried, I could not get #4 Injector to seat flush into the fuel rail. Please let me know what you think I should do? Replacing fuel rail is something I wanted to avoid if at all possible. Thanks again!

 

It looks as if that #4 injector's O ring has not stayed in its groove, but has rolled out and down and ended up between the flange and the rail.

If that keeps happening on multiple attempts, then I suppose there could be something weird about that bore in the fuel rail. I guess you could get a new rail, fit all four injectors into it on the bench with good light and access, then swap that rail for the old one.

 

Yes, I did everything you said and much more ... frustrated and scared to see fuel gushing out of #4 no matter what I tried. I tried #4 with multiple O-rings, few new and even original ones. As far as I can, the O-ring slides inside just fine with some lube and I did twist left and right very gently while inserting it. It just does not seat flush to the fuel rail no matter what ...

 

Hi @ChapmanF : Thanks for your suggestions. Please read my post # 15. I do not think O ring rolled out. That black portion you can see in the picture is not O ring, it's part of the injector. The O ring color is orange and it slid inside just fine with some lube with the method you described in another post. Thanks again!

 

I'm not sure how much more I can suggest from here. Sometimes there are those situations where you know what has to happen, and you just have to keep generating ideas for what to try until you can make it happen.

 

Thanks again! I will try one more time with another brand new o rings that I am waiting. If that does not work, I will decide to replace the fuel rail or something else ...