Diy - Gtr Injector Replacement

[MrStabby]

Replacing just the seals or the entire injector set is quite an easy job. This work was done on an R32, but since the RB26 didnt change much over its lifetime the 33/34s are hopefully the same. All RB26s use the same injectors.

Note that if you change to a different injector size you MUST have programmable engine management.

WARNING: You will spill fuel during this work. I suggest you;

- Make sure there's no flames or sparks nearby, so no smoking (duh)

- Work on a cold motor

- Have a powder or foam fire extinguisher handy, and make sure you know how to use it (eg if there is a fire, first stop the fuel source, so dont forget to turn off the ignition to stop the fuel pump, then aim the extinguisher at the base of the fire - dont waste it by pushing the flames around). A hose can be dangerous in a fuel fire...

1. The day before you intend to do the work, thoroughly degrease and clean around the injectors.

2. Locate the fuel pump fuse, start the motor then pull the fuse. This will relieve the fuel rail pressure

3. Remove the strut brace and cam breather hose

4. Remove the three 5mm hex key bolts from the black plastic injector wiring cover (just for a bit more flexibility)

5. Disconnect TPS connector and the connector next to make some space

6. Remove the two bolts holding the fuel rail on, then gradually ease the fuel rail up and out. The injectors will probably come with the rail. You dont need to remove the fuel connections to the rail (which are tight)

7. Ease the injectors out one at a time and try to catch any fuel with a rag. If replacing seals, remove the o ring from the top of injector and the rubber mount from the bottom of the injector or the cylinder head if it didnt come out with the injector. I used a watchmakers screwdriver to remove the o ring. If replacing injectors remove the metal clip from the electrical fitting, swap the injector and replace the clip. The outside of the o rings should be smeared with a little rubber grease.

8. Once all the seals or injectors are done, mount the bottom of the injectors then line up the tops of the injectors with the rail and ease it on. Carefully press the rail onto the injectors. Install the rail mounting bolts finger tight then do them up evenly a few turns at a time each side so the rail isnt skewed as it goes on

9. Clean up any spilt fuel. Really. You'll start the motor soon and probably don't want to see it on fire.

10. Replace the wiring connectors, hex bolts and cam breather hose.

11. If you are installing injectors of a different size you need to update your ECU to cope with them.

- If using Nistune; turn the ignition on, load the config from the ECU, save a copy of the config to disk. Select 'Operations -> Resize Injectors'. Enter the original injector size and the new injector size. If the current injectors are OEM you can pull the size in with the 'Factory CC' button. If the new injectors have a different latency to the old ones, use 'Injector Latency -> Change Constant' to make the correction. Apply the new config to the ECU and save the new config to disk using a different filename.

- If using PFC; refer to: http://paulr33.skylinesaustralia.com/docs/...erfc-faq.htm#57

FWIW OEM GTR injectors have a latency of 770 micro seconds.

12. Start the motor, and watch for any fuel leaks. As the engine is cold it will be running open loop so if it doesnt idle well it probably means the injector re-sizing needs a tweak. Putting a smaller cc number or larger latency number in the resize option will make things run richer, and vice verca. For Nistune if you are changing the cc number remember to use the last figure you entered in the Current field - not the factory number. If you dont understand how cc and latency settings effects fuel delivery in different ways take it to a tuner.

13. Go for a short drive and re-check for fuel leaks

14. If you changed injectors verify AFRs are good with a wideband o2 sensor (all dynos have them). Light load driving is fine in the short term, as closed loop should compensate when the engines warm.

15. Reinstall strut brace and you're done!

[Sean'O]

Hey buddy,

Just wanted to say thanks for the great DIY, changed over my injectors the other day and this thread made it a breeze

Cheers,

Sean

[B-rice]

Just a question is there a restriction on the length of injector you can use. I have 43mm oring to oring injectors.

[scotty nm35]

You will need the correct length 14mm injector with a 10.2mm adapter. If you try and fit injectors that are too long or short you will need to modify the rail spacers accordingly.

Also, the lower 14mm Oring needs to be replaced with a larger square section Oring.