Installing Injectors - Do's and Dont's

[Turbo Tits]

Hey people, I'm installing larger injectors on an rb25 and I need some help.

What's the procedure after you have removed the top half of the plenum? Does anyone have any tips? What worked for you? What didn't? What lubrication should you use on the o-rings to help locate the new injectors? Oh, and i remember reading about having to pressurise the fuel rail afterwards- can anyone shed some light on this?

Basically, anything you can think of that would help would be much appreciated.

[Bullant47]

Hey people, I'm installing larger injectors on an rb25 and thought it would be nice if everyone who has replaced their injectors (on any RB) could post their experiences to make it a smoother exercise for others doing it for the first time.

What's the procedure after you have removed the top half of the plenum? Does anyone have any tips? What worked for you? What didn't? What lubrication for the o-rings? How do you pressurise the fuel rail after installation?

Basically, anything helpful that you can think of.

Make sure you have all new "o" rings, there are 2 on each injector, and are usually not supplied with new injectors (Nismo). Nissan can get them. Their are a few other little bits you can do at the same time. I'm thinking of a little rubber bit that sits on the top of the injector.

Hope that helps.

ken

[Turbo Tits]

thanks for that bullant. what lube should you use on the new o-rings?

surely there has to be more to it than that, anyone???

[Bullant47]

thanks for that bullant. what lube should you use on the new o-rings?  

surely there has to be more to it than that, anyone???

Yes there is a special grease to use on the "O" rings. Repco sell the stuff..I think it is PBR rubber grease.

I watched my mechanic do the whole job twice cause the first time he didn't realise there was a "O" ring missing off the body of the Nismo injectors. When he pulled the injectors out he didn't compare the stock with the Nismo's.

The hardest part of the job was taking out and replacing some bolts under the inlet manifold.

Hope that helps

Ken.

[igor]

What about the throttle body and the plenum gaskets? Do they have to be replaced?

[Bullant47]

What about the throttle body and the plenum gaskets? Do they have to be replaced?

No..you will only see the Plenum gasket which is a substantial gasket. If your carful when you seperate the top of the plenum from the bottom you should be fine without replacing anything.

Ken

[Turbo Tits]

sweet stuff bullant, youve been a great help

[fresh]

as far as pressurising the rail goes, i tinhk it means just tunr the key as far as possible without actually starting the car, this should whirr up the fuel pump, igve it a couple of sec (or more if u r paranoid), then start away

[BigDatto]

DO:

be prepared for the job to take longer than you think...

have a can of silicon spray handy (OK to use with fuel system components)

have band aids/first aid kit handy (you WILL cut your hands on the plenum casting dags)

have a slim 10mm ring spanner with slight offset. This will clear the rocker cover for the "ultimate bitch" bolt. You'll know which one I mean.

have carby cleaner aplenty

have some Loctite or similar

be aware that there are (6 from memory) black washer type spacers between the rail & head. If you drop one, you might never see it again.

have a long extension for your socket. 18" is good.

raise the car on stands before you commence.

strong lighting is essential.

and rags aplenty.

Replace all fuel hose w/ proper efi hose & clamps - don't be dodgy & reuse the brittle oldies or regular hose clamps

Replace the filter too

good idea to saturate & scrub all the carbon & oil from the top half with carby cleaner

you'll need to remove a bunch of vac hoses from under the plenum to get your socket on the bolts - pain in the arse.

DON'T:

use excessive force to remove the injectors - they will be very tight. Lots of silicon spray & gentle tapping helps.

let swarf/dust/dirt into anything.

over torque the plenum bolts (everything is alloy)

This is a royal biatch of a job- but very rewarding. If i had to do it again I could in less than half the time, hope you gain from my experience.

[Jolinator]

big datto is correct, had mine off to when i polished the manifold, and also had the injectors cleaned whilst at it

also to add to the do list, you may aswell replace the plenum gasket etc, mine was stuffed as it was glued down with some goop shit however when i took the top half off an rb25 it didnt have it so maybe its an rb20 thing, gaskets arnt expensive anyway,

[igor]

Let me get this stright: You need to remove the top plenum cover from the bottom half and raise the whole thing(with the TB still attached up to get the fuel rail out)?

[SLY33]

I found removing the TB made it a million times easier to access the bolts on the underside of the top half of the plenum. But im sure youll find a Mr.Fantasic on the forum that'll say you wont have the remove the TB. But really, its only another 5 minutes work.

[igor]

I ll give it a go tonight. I might try and take pictures to post a up a how-to.

[blind_elk]

It can be done by just removing the TB. Then remove all the crap hanging around at the front of the plenum (FPR, PCV, etc).

There's no need to split the plenum.

[igor]

So it's possible just to disconnect the TB from the plenum without having to split it and hence avoid undoing all those upside down bolts holding the two parts together? Or is it the fuel rail that those pain in the arse bolts hold?

[igor]

Just pulled the fuel rail out. What a royal paint in the arse it is!!! I took some pics too...

[USRB25S13]

I did my injector swap a few months ago and I didn't remove the upper plenium. I just took off the throttle body and all lines under the plenium to get the rail out. It was a pretty easy job. I have an inpact screw driver to take the injectors screws out. That makes a big difference.

[BHDave]

I've done it a couple of times on an rb25 aswell, didn't need to remove the top half of the plenum, just the throttle body and coolant bleed at the front.

On rb20 i didn't even need to remove the throttle body.

[Abo Bob]

On NEO I had to remove the top of the plenum. Tried for hours to do it without.