I'm stumped here. am I missing something?

I'm using this manifold





these diffusers



injectors & grommets/o-rings set up like this (gsl-se injectors)



I bolt up the rails, and I end up with this much slop. Injector moves up and down approximately the width of the upper grommet.







any ideas?

 

What's the part number on that injector??? 19550-??????

 

Series four or five engine?

Is that a series four fuel rail being put on a series five intake? Just asking. Manifold seems series five for sure but the rail is???????????????

 

195500-0900

i'm not certain what series everything is, but I thought it was all S4 stuff

block is s4 na. turbo is s4. manifolds i'm not exactly sure

 

the injector bleeds are s4 and you are using an s5 manifold.
check mazdatrix,they show pics of the bleeds/diffusers..they are different from s4 to s5

 

Those are 680s. Probably not the problem though.

I think Mysterstyx is on to something there. The grommets are also different than series four. That is a series five manifold since I see a vac hose running b/t the two secondary injectors air bleeds.

Maybe a problem with the fuel rails? I don't know for sure. Series four vs series five?

 

are they really? atkins rotary lists them as all the same 84-92. i just ordered s4 ones... hope they're right.

the manifold being s5 sounds like the problem though... but the s5 air bleeds look a LOT taller, like way more than the gap I have now.. no?

 

So, what we do know is...

- S4 N/A block
- S4 turbo
- S5 LIM
- 680cc fuel injectors *('84-'85 GSL-SE)
- *S4 TII fuel rail

 

also.when you go to put the injectors in the manifold with the NEW diffusers they are gonna sit ALOT more snug than anticipated.
WHY?: because you are using the s4 rail on an s5 manifold.
To alleviate that problem( and this is according to parts list given on the RisingRPM fuel rail kit) is you need another 4mm to make it fit.Correctly.
..and that reasoning is that they use the Same rail for BOTH the s4 and S5 ..BUT they use 4mm to allow the injectors to seat correctly on S5 ONLY!
..........
So The conclusion is S4 rail,plus 4mm under the rail(between the rail and manifold) Plus S5 manifold With s5 diffusers Equals a Happy Camper!

 

i think this might be right, i built an S5 using an S4 secondary rail, and it worked fine. i do KNOW that the injectors and air bleeds were the proper S5 parts

 

s5 manifold with s4 fuel rail
there is fundamental differences in the height from the mounting bosses for the rail
and there is fundamental differences in the stack height of the two piece difuser ( s5 ) to the single s4

usually,, with s5 diffusers, s5 LIM and s4 secondary rail ,, you have to space the rail UP about 2mm with washers under the mount pads as it is crushing too tight

however-
it seems with s4 difusers ( one piece ) the problem goes the other direction, too loose

from experience with other injector brands fitting without the difuser
i have found that for every section of difuser you delete,, you replace the lost stack height with an extra base O ring
so,, in the OP case,, he can fix the isse right now simply with another ( mazda ) flat sided rubber base O ring
( note i have said mazda,, some replacement o rings from other brands are very slightly lesser OD )

OR

the OP can go for the s5 ( two piece ) difusers AND a couple of washers under the mount pad


NB

US users can note that in aus,, the s4 rail onto s5 LIM is a common swap
,,, we have JDM counter current s4T fuel flow direction in our s4T rails
and we have s5T US market co-current flow rails

swapping the s4 secondary rail onto an oz or jap engine amounts to two dampners ( if still fitted ) and no reg
-- an easy solution around the cut shut required to fit AN fittings to s5 rails when fitting an external FPR

 

amazing info everyone... i was thinking of just using two lower grommets. it should fit right, i just wasn't sure if that would be optimal injector placement.

also bumpstart, im pretty sure both s4 and s5 secondary diffusers are one piece, only the primaries are 2-piece in the s5

 

the s5 secondary difuser is doubled O ring top
and is the equiv of using the s4 secondary difuser,, with the s4 primary top section added

IE , in effect the s5 secondary is a double height difuser like the primary ( s4 and s5 ), whilst the s4 is only half that stack height off the seat

 

PS
you can **** the difuser away entirely if you replace single heights with more base rubbers
( the difuser is Ok with stock injectors,, but not with higher flowing ones and higher boost, and i advise they go in that case )
ie,, in this case ( s5 LIM, s4 rail ) you would have three O rings under each injector
,, and on a s4 LIM,, with s4 rail ,, two

and this is what i will often do if fitting EV1 type rochy injectors ( which have inbuilt diffuser in the injector )