RB25 fuel rail / Greddy manifold help

[AZhitman]

Rb25 with real Greddy (not Freddy) manifold, using stock fuel rail. We're getting some fuel leakage from around the injectors, on all six.

Pulled fuel rail and it appears there might be 2 issues:

1) There are only 3 bolts holding the rail in place (lower mounts). Seems there should be a provision for the top two bolts on the rail, shouldn't there?

2) The grommets for each injector seem to fit firmly around the injector body, but are a loose fit in the manifold injector ports. Is this a simple matter of replacing with new, or do I need to use a different grommet?

Recently had a rail service done by Deatschwerks, so the o-rings on the injectors are relatively new.

Thanks in advance for the helps!

[Darius]

Are the injectors leaking up at the o-rings?

I remember the grommets being kinda loose in the ports by themselves but pushing the injector cups into them widened them out a bit. It hink as long as the grommets are pushed forward towards the runner and against the sealing surface, they should be fine. If they aren't pressed tightly down by the injector, can you shorten the rail mounting spacers to push the injector cups further down into the grommets?

It would seem that if you noticed a leak that it would be coming from the o-rings though.

[AZhitman]

Makes sense.

It just seems like something else should secure the fuel rail, not just those 3 bolts through the tabs. Seems like it doesn't press the injectors into the ports evenly.

[Coolwhip]

Surprisingly the two bolts do the trick. Got any pictures of the mentioned leaking areas?

As previously mentioned, the grommets in most cases have some play sitting on their 'seats' on the manifold and require the rail to press them firmly against the manifold. Shortening up those spacers on the rail will provide further pressure on those grommets. However, do note that the rail may want to bolt down at an angle if done too much. You mentioned a rail service was performed, could you verify that the tabs were not bent or modified at all? Just a thought.

[AZhitman]

I already cleaned up the manifold. I'll get a pic tonight.

Mine has 3 bolts - maybe I'm missing something?

[AZhitman]

Here you go, guys - Hopefully these pics help.

Just seems like fastening the top and bottom of the rail would straighten it out in the ports... maybe I'm overthinking this.







Thanks!

p.s. I'm also noticing it seems like my rail may be slightly bent... that ain't good.

[Darius]

OHHH these are side feed injectors?! For some reason I was picturing top feeds.

I would pull the injectors out and check the top o-ring for rips/tears. If they aren't lubed up with vaseline before they go in they can get snagged, rip, and fuel leaks out the top. Otherwise, there shouldn't be a problem with fuel coming out of the grommets unless the rail is not tightened down enough.

[jbracy7]

Maybe the greddy manifold has over sized injector ports,the best i can guess

[Funktown240]

Are you using a spacer or washers under the mounting tabs?

[AZhitman]

Spacers.

[Darius]

I don't think I used spacers under mine. I think I just tightened them until the rail was tight.

[AZhitman]

Gotta figure this thing out before next weekend...

I haven't pulled the injectors (I let Deatschwerks do that when they did the Rail Service). Too much chance of me screwing something up.

[Darius]

Have you determined if they are leaking out of the top o-ring or not? Prime the pump and check?

[l0nestar]

I'll check when I get home.. hopefully..

[chad b.]

Throw that crap in the garbage and get a GReddy top feed rail and some real injectors and stop d!ck around with that side feed s***. Problem solved.

[Darius]

Throw that crap in the garbage and get a GReddy top feed rail and some real injectors and stop d*** around with that side feed bullsh*t. Problem solved.

I agree to a certain extent. If you're just looking for ~400hp, side feeds are acceptable but don't get you much past that.

[AZhitman]

I don't need >400 hp in this car. Reliability and drivability is the goal.

I'll look at a different rail, but I don't need to change injectors.

[LSDrift]

I'm having the exact same problem! I was using the factory injectors, never removed from the rail since I bought my motorset and didn't have a leak. Through a learning experience while I was trying to diagnose a dead cylinder I ended up replacing all 6 injectors with OEM ones from Deatschwerks. Shortly thereafter I started getting a fuel smell after bouts of hard acceleration. So I've done everything from buying new sets of o-rings from deatschwerks for each injector and lubing them up thoroughly, to getting new insulator rings for each injector to sit in the manifold. Still have the leak problem and can't figure out whether it's coming from the injector body, or a bad seal with the manifold itself...

[FAST-DATSUN]

fuel injectors must be flipped 180 deg to prevent cocking of the rail when injector clips installed causing a leak.. Yours look to be in the stock position.....

[AZhitman]

FD - I actually clearanced the manifold runners so that I can run the injectors like this... Didn't want the wires sticking up. There' about 1mm of clearance under each injector clip when installed.

Good catch though!

[USMCgetsome]

i had that prob years ago. I simply used a permatex sealant around each injector to that grommet also did the same to the grommet to the manifold seems like overkill but you guys are runnin way more boost than i ever did.