I all, I'm new here, finally joined after looking for a while.

I just bought the moss fuel rail, http://www.miatamania.com/Shop/ViewP...eIndexID=77198, for my 91. Now, after installing it, fuel is leaking from both ends of the rail. On the end with the 90 degree nipple, it is leaking from where the nipple threads into the rail. On the other end, it leaks from both the threads and between the flanges of the fuel pressure regulator and the fitting on the rail. What do people suggest for something to stop the leaking? Is teflon even appropriate for fuel systems? And how should I properly seal the two flanges, I see there is an o-ring, but it doesn't seem to stop the leaking.

 

I'm pretty sure teflon will be rapidly degraded by gasoline. Maybe loctite?

 

I had thought about it, but I'm not sure which kind of loctite would work.

 

Play it safe and go with the best they sell?

 

I'm wondering if the gasoline will dissolve the loctite?

 

I've used loctite in plenty of harsh environments and it held up...I just don't know if it'll be good for this particular application

 

Fuel melts teflon. Seriously, hold some teflon tape in a little puddle of fuel and it will vanish within a minute or two. I learned this from BRP when my coldside supercharger suddenly started basting itself in gas. I was instructed to use JB Weld to connect the fittings to their fuel rail. After I did that, there was no problem.

There IS a type of teflon tape that's safe to use with fuel. It's sort of yellow colored. I think you can find it at a local Lowes or Home Depot. It will say something like "safe for gas" on the reel. But after my not-so-wonderful experience with the melty stuff, I decided to play it safe and do the JB Weld.

This stuff from Loctite is supposedly safe too.
http://www.amazon.com/LOCTITE-30534-.../dp/B0020UOZTU

 

Yellow or pink.

Don't use it though. I use permatex.

 

Permatex #59214 - High Temperature Thread Sealant

Generic "Yellow Gas Line PTFE Thread Seal Tape"

Read the label on the yellow tape, make sure it says "Gasoline" on it.

I'll trade you my leaking M-Tuned for your leaking Moss...

 

I'll look for that stuff. Thanks for the offer, but I figure I'll solve this headache, I'm not ready to throw in the towel just yet, although the dual feed would be nice

 

FWIW I like the yellow PTFE tape, don't have to wait for it to dry overnight. Just be sure you wrap it in the direction of the threads, and I like to run a fingernail around the threads to seat the tape before I thread it together.

For that O-Ring on the regulator, is it new, or the one that came with the car? You might just want to stop by the Mazda dealer and get a new one. Your car is a 91, so that means the rubber O-ring is now 20 years old. They don't last forever, especially in a fuel and heat environment.

And yeah, I understand. My M-Tuned blows craploads of fuel out between the injector pockets and the injector top, almost like a couple of the pockets are oversized ID or were drilled too deep. M-Tuned keeps telling me to make sure to lube my O-Rings when seating the rail, or that I tore a seal when installing. Funny how the same injectors/seals/install & lube method works for the stock rail with no leaks. Bah... At least the side of my block is nice and clean now.

Good luck with the rail, I'm sure it will work great once you get it in there.