My 86 has the 88 turbo parts put on it and seems to have the 91 injectors PN: 195500-2020. From what I understand everything is S4 but those injectors. I do have the diffusers and had the injectors recently cleaned and new grommets.
I now have this gap and I don't know if it was there before. The space is about the same size as the rubber spacer. I am very lost and only found a few threads that have this kind of issue, and didn't see anything telling me the problem.

Now the problem.
Apologies for the picture size.

 

What fuel rails are those? It looks like s5 from the primary fuel rail having the built in fuel pulsation dampener.

I can see you have a s4 lim, correct me if I’m wrong.

Maybe the s5 fuel rails on s4 lim is to blame?

this thread below states there is a 4mm height difference, which looks to be the gap you have.

https://www.rx7club.com/2nd-generati...e-fpr-1006526/

 

the S4 and S5 also have different lower Grommets, the S4 is N326-13-257 vs the S5 N350-13-257

may not be the problem, it looks like the 4mm thing ^^^^

 

Yeah I’m “guessing” it’s not an immediate danger but I’d recommend searching if it is. I don’t risk it when it comes to fuel.

id think the upper oring seals the injector to the fuel rail, and the upper grommet is more of a bushing for the fuel injector. That 4mm gap is probably a risk to shock/vibe and increases wear on the upper oring and lower grommet.

 

yep, the upper O Ring seals fuel (injector to the rail), the lower only seals the injector to the manifold, so its vacuum, mostly. i suppose a taller lower seal would "work", but it would probably be better to find an S4 rail?

 

So I googled the different rails I it does look like a S5 rail. I'll find a S4 rail to replace it with. I don't want to risk it with fuel lol. Thank you for the help and I'll add photos if that's the solution.

 

Can use both s4 rails, primary and secondary. Just note the s4 primary rail uses a fuel screw on pulsation dampener, that can leak with age and cause an engine fire. Hence the redesign for the s5. My s4 fuel pulsation dampener was original and started leaking around 120k miles. Put a new one on and was good to go. I’ve since gone s5 turbo engine so am using s5 rails now.

just fyi.

might be worthwhile seeing if you can use your s5 primary with s4 secondary rails. Would have to line them up and see if the rubber fuel hose would fit.

 

The S5 primary bolted down just fine, i'm waiting on a S4 secondary to hopefully fit it all together.