First off, I have a 1997 RS... I was attempting to install my SFMU this past weekend and I mounted the unit, and was running the line from the feed port on the SFMU to the end of the fuel rail. I took out the cap and the schrader (sp?) valve. Well when I tried to screw on the -4 AN fitting onto the fuel rail, it wouldn't screw on, almost like the fitting was too small. I followed the diagram for the installation of the SFMU using Earl's fuel fittings but I couldn't get that fitting to fit. Anyone have the same problem that could offer a solution so that I can get this thing running? Thank you!!!

Chris

one thing you could do is check the threads on the cap vs. the threads on the -4an fitting, if they're the same then you're gold, if not then

Representing the Central Cali chapter of 2GNT!
(I think I'm the only member )

I tried to find a bolt that would thread into the cap so that I could double-check it with the fitting but I couldn't find a bolt that would work. Has anyone here followed the SFMU diagram on this site and ran into this same problem? Do I need to purchase an adapter to make it work or am I missing something?

That schrader valve is a 4an fitting. If there is an issue with it fitting on, check the line you are using. I do not use a SFMU, but I have never heard of anyone having this problem either. You remembered to remove the check valve first right?

I am a little confused though... if the fitting is to small why is the hose not threading on? If it is indeed too small would it not just slip over the fitting on the rail? Or are you referring to the hose fitting?

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2012 2500HD LML

Yes I removed the valve before trying to put it on. The fittings fit onto the stainless hose perfectly and are snugged down tightly, but it is almost like the fitting isn't big enough to get over the end of the fitting on the rail. I am very confused as to why it won't fit. I don't want to use too much for because I'm afraid I'll snap off the end of the fuel rail.

you don't have a -3an fitting by chance do you, cause then it would be too small for sure.

Representing the Central Cali chapter of 2GNT!
(I think I'm the only member )

I bought all of the fittings from Summit Racing and used the quantity thing to buy 5 of them. They are all the same and I tested a fitting onto my SFMU adapter assembly which is used to allow the use of -4AN fittings onto the SFMU, and the fitting fit onto that so I know that they are 4 and not 3.