Well you can add me to the list of know KG PARTS fuel rail leak. I been running their rails on various cars I have owned and just recenty I got the scare of a lifetime. When I parked my car in my house a strong fuel smell came about when I walked pass the car. I pop the hood and I hear bubbles. I look under the UIM and My primary rails where leaking and there was a puddle of fuel on the lim/housing area.Who knows how far I drove like that. Now I am on a debate do I trash the rail or fix the issue.

I have done the following.

NEW Fel-pro chevy truck o rings
NEW RC injectors oring
Mazda bottom o-rings
Rotary aviation Oring

What have you guys done to prevent this. Hell I even lowered my Fuel pressure to an unsafe low and STILL LEAKS!!!!!

 

The rail itself is extremely simple. So I'm not sure how that can be the problem. Do u have the right size o rings on the injectors to match the rail? Maybe go one size bigger.

And use fuel safe sealant on the NOT threads that screw into the ends of it. Not sure how else it could be leaking

 

I have never had an actual rail fail by itself. If you have a leak, its almost certainly installer error or the wrong parts were used. Use teflon tape that is RATED FOR FUEL on all pipe thread conenctors. DO NOT use tape on the -an compression fittings. Lube up all the o-rings so they do not tear or shift when the rail is put over them. Assembly all hoses and -an fittings properly and tighten properly with -an specific wrenches. We use Snapon at the shop but you can get an inexpensive set of -an wrenches from Summit Racing as well as aluminum jaws that go in a vice and hold the fittings while you assemble them. Pressurize the fuel system and find exactly where the leak is. KG makes good stuff. Doubt its the actual rail.

 

Fittings are fine leaks is obvious. Hell it's shooting straight out. I am going have to take the rail and oring to autoparts store and go diving.

 

What o rings do you use man

I am running RC 1000 injectors

 

a local guy rx7 burned down last week due to a fuel leak and he was running ID injectors with KG rails, now i see this post.. also i had leaks with my rails as well and swapped to the chevy orings and it worked just fine. But i decided to just replace the rails to the FF ones and i couldnt be more happy with the tight seal.. i am just saying..

 

Thats exactly what I am talking about after trying it again today I came to conclusion the KG PARTS rail bracket might be the culprit. Its very weak and when you try to tighten the lines it moves. I am about to buy a new set of rails probably the FF set or CJ because if the stiff mounts and new cnc machining process.

 

That's a bit concerning for me...

I have had KG fuel rails on my FD for almost 2 years with NO issues...I did have my fittings welded to the rails though..HHHMMMM

Alex, can you post pics or video so I can see where the leak is..Want to check mine to make sure I have none...

L8R

 

It looks like he's saying the leak is coming from the holes where the injectors go in, not the end fittings. If that's the case, it's either the O-ring, or the hole is not a perfect circle.

I'm guessing it's not the hole. And you can't just go to the local auto store and look for an o-ring.

Just call KG Parts and have them send you an assortment of rings. The inside diameter needs to match your injector, and the outside diameter needs to match the rail. Tell them which items you are using and I bet they can send you the right o-rings. These rails and injectors have worked fine on tons of cars.

 

When I built my car I had quite a few issues with the KG rails. Honestly, I don't think it was the rail per say, but a combination of the rail, mounting, and my inexperience. I know what you mean about the mounts. The angle and positioning makes a proper adjustment hard. To get the injectors perfectly flush, tighten down the bolts, and have the allen nuts perfectly adjusted is a little tough.

After continual fuel leaks when I was building the system, I finally had my wife climb in the bay and press down evenly on the rail as I snugged everything up. That did the trick. Fuel system stuff can be tricky, and as you know, there is NO room for error.

And it's ANOTHER reason every Rx7 owner should be carrying a fire extinguisher.

 

I have installed the KG rails twice on my car and on a friends car as well and the problem is the angle of the rail, it is not a straight fit.. In other words the injector sits sideways up in the rail hole so it's not a perfect Oring seal. This is why i used the thicker Chevy orings and even though it worked for me I just couldn't just let go of the tought.

Another reason why I like the FF rails is because they took everything into consideration when designing these rails... This is not a sales pitch by any means but I am just expressing how happy I am with this product.



-----Quote from FF when I asked about the offset of the hole---
For a couple reasons. First off we have seen rails in the past where the bore goes all the way through and leaves a sharp edge where it meets the main through hole. This chews up o-rings terribly and doesn't leave a flat surface for the injector to sit against. So we wanted to give the injector a nice solid stop and keep everything aligned. It is off-centered to maximize the flow from the main through hole.

 

So just build new mounting brackets out of some thicker angle aluminum so they don't bend and seat the injector square. max $10. Done.

 

KG rails have been around forever and used on probably thousands of RX-7's. I know I have sold and installed hundreds of rails over the years and there have been minimal issues with them. Typically if there is a fuel leak, its the o-ring that is the problem.

 

Those FF and CJ rail do look a lot more solid than the KG one.

 

I emailed Keith and he is going to send me a new a set of orings.


In no way I am bashing him on his rail. This thread is solely for caution and problem solving my issue.

Again I have swapped out orings with new orings 4 times.
Fuel pressure is at 35psi
Fittings and hoses are not leaking
Injectors are new
Rail itself seems good and it's bore.
I have used the kg rails in all of my builds and am a firm believer they do the job.
User error my a$$ they worked fine for 3k miles why all the sudden the leaks?

I need part numbers for orings guys what are u using.

The only guess is the bracket like everyone has been saying on numerious post. No I don't want to fabricate a bracket it's either oring gets resolved or rail is for sale.

 

I bought my KG Parts kit directly from KG Parts and experienced a leak with both of the supplied injectors with the kit.

The injectors were leaking at the seams of the injectors themselves! I bought the kit with Bosche injectors and they both came apart at the seams within a year. When I notified KG Parts they basically told me tough **** and sold me a set of Siemens injectors.

All I can offer is to look at the injectors themselves and see if they are seeping at the seams. Happened to me.

 

^^^^^My injectors are new and its leaking between the rail and injector mating section. Noth the injector.



UPDATE!!!
Keith sent me o-rings that work with 99% of injectors been used with the rail. I will try them and include the part number for them if it works for me.

 

I had the same problem with my KG primary fuel rail, the problem for me was when under pressure the rail would actually lift a little bit. The bracket that came with the rail would bend, so to fix it I now have this:


No leaks now...

I tried changing o-ring's and that helped to a degree but this was what finally eliminated the issue.

 

I recieved two sets of diffrent o-rings from Keith and still leaks.

I pursued bending the bracket to create force and doesnt leak a lot but still leaks. I am out of options I think I will buy the FF rail and figure the rail out later or sale it.

 

You need to hold the rail with an adjustable -an wrench when you tighten the fittings.

 

Ok updates as requested.

Brian sent me a new Bracket and bingo it doesnt leak. Seems over time the bracket gets bent with the removal and installs. Also the main culprit when putting the fuel lines back on the rail moves a bit when securing the fittings. That is all you need for a leak.

After the bracket it stop the leak but I went with Full Function Engineerings rail and injectors system. Super sturdy and very easy to install. best of all no adjustments.

So if you get a leak and you have done the following-
1-adjusted the rail
2-changed o-rings
3-lowered fuel pressure

and it still leaks check the bracket!

 

Pretty sure everyone was telling you that the entire time.

 

Today i had this same issue with the KG Rail
I think they drilled one of the holes too big
Fuel was leaking from the O-Ring that was supplied
I went to the autoparts store to get a bigger o-ring and that didnt work either

Going to go with FFE Rail and send mine back.

 

Can I get a link to some of these other rail options, I know when I installed my KGParts rail, I had to use spacers. I thought that was odd. No leaks though.

 

I found that if you get the injector into the rail prior to tightening it down, the o-rings sit better in the rail. It takes some oil and a flathead screwdriver to get the o-rings in there by hand, but it works. Otherwise, the ring may not go in flush and it could get damaged, or sheared, when bolting the rail down.