Capping A Fuel Rail - Page 2 - Diesel Bombers

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Old 08-16-2008, 08:07 PM
dalton06's Avatar
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where do I get the "real cap" ? Complicated or easy to do like this?
Old 08-17-2008, 12:25 AM
Red_Rattler's Avatar
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Or you could just get the dual fuel line kit.....
Old 08-17-2008, 02:25 PM
Diesel Fan
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Floor It sells the cap that takes the place of the relief valve fitting. very nice piece. the dual feed line kit doesn't really do much for performance, but it will act to cap the rail.
Old 09-10-2008, 02:53 PM
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Got her plugged. Just so everyone knows, need a 3/8 FT(24 tpi) tap and 3/8 24tpi set screw.
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Old 09-10-2008, 03:15 PM
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Appreciate the re-loc!!!
Old 11-06-2008, 10:30 PM
wildbill's Avatar

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Right, need a fine thread tap. But which size plug? 1/8" or 3/8"? I forgot when I did mine.

Last edited by wildbill; 11-06-2008 at 10:32 PM.
Old 11-09-2008, 10:51 PM
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What is this mod for? Im
Old 11-19-2008, 07:28 PM
Mr. Miyagi's Avatar
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Originally Posted by dieselgrl4life View Post
What is this mod for? Im
Wow, you're alive after all.

It keeps fuel from returning over relief--the valve will open but no fuel can get out so it'll continue to keep the rail pressurized.
Old 11-25-2008, 10:49 AM
Diesel Fan
Join Date: Mar 2007
Location: VT
Posts: 23

Ok, stupid question. I can see the possible damage that might happen if you cap the rail and it keeps hitting the roof. Something has to give somewhere.

I can understand that if it is capped and it keeps the rail pressurized, you will keep the fuel in the rail compared to draining back through the relief valve when you are in a WOT situation.

But, my truck is basically still stock (2005) except with RokkTech Sensor to advance timing, slightly better airflow (not aftermarket), RokkTech muffler and a somewhat heavy right foot now and then. Would this benefit me since I really don't have a guage to see what my current fuel pressure is when going down the road or even WOT? Would I feel it with my SOPG (seat of pants gauge)?

102,000 miles on truck so I don't really want to blow the thing up but always looking for a better performance mod if possible. Yes, some day I would like to purchase Smarty and all the guages that I currently don't have, but in the mean time. As long as it wouldn't blow it up upon first WOT, should I be fine?

How would I tell if something was starting to go bad due to this mod? Popping noise, damage to injectors, anything like that?

Worse case is take it back out.

Just asking. Thanks. Scott
Old 11-25-2008, 02:27 PM
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I'm no 3rd Gen guy but I think this mod only benefits those who have upgraded their fuel delivery system to the point where the engine demands exceed the system's factory limits.

Maybe...just guessing here.

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LinkBack to this Thread:
Posted By For Type Date
rail cap vs. dual feed line - Page 2 - Competition Diesel.Com - Bringing The BEST Together This thread Refback 04-03-2009 10:50 PM
Hard Starting. - TDR Roundtable This thread Refback 10-05-2008 09:18 PM

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