how hard is it to swap out the fuel rail?
 

Anyway to do it without ripping off the Intake manifold? Just got a dual feed home-made rail off e-bay for 20 bucks and would like to swap that inplace of my stock one. How easy is this to do?

Check out Hakuna's miata page. He's got a good write-up with photos and shows how easy it is.

it should be simple as long as the new rail is made to fit well. Also if you dont know how to purge the fuel system, here is my preferred way: First undo the gas cap, then look under the dash by the steering column for a little yellow plug with 4 wires on it. It may take a few minutes to find the one I am talking about, but when you find it, pull it out and then start the car and let it run until it dies.

Easy.

Depressurize the system like akaryrye said, or just drip gas everwhere. The clip is obvious, it's the big yellow one.

Have fun.

nah dude take off the fuel lines, take out the 2 bolts while not losing the spacers and reinsert and align the injectors torque down hook up fuel lines and go. It is that simple. Just pop the gas cap to releive pressure the dripage wont be horrible.

the new one is just a stock rail that someone drilled, tapped, and put a thingy in there... looks pretty much like Brain's DIY one.

popping the cap won't relieve fuel pressure at the rail, but magnas right, the drippage aint bad.

saw it. It's DIY style.

It's easy but a bit of a pain in the ass.

OK, just for you bud. I wrote this from memory, so some of the bolt sizes might be wrong. If you start with a car that hasn't been run in 24 hours, there will be no fuel pressure in the rail, and no fuel will leak out. If the car was run recently, have some towels handy and prepare to stink like fuel.


Step 1
Remove these four 8mm bolts with a 1/4 drive ratchet to separate the valve from the intake manifold. A 3/8 won't fit in the lower bolts. The bottom forward bolt will not pull out until after the valve has been removed from the mani. Just loosen it all the way and don't drop it.
http://img256.imageshack.us/img256/1117/94832543dz0.jpg


Step 2
Push the valve forward and tuck it out of the way. The next item to remove is the breather tube between the intake manifold and cam cover. Use pliers to compress the clamps and remove the tube.

http://img73.imageshack.us/img73/7991/85879285bo7.jpg

Step 3
Now you'll remove the fuel pressure regulator from the back end of the fuel rail. It is secured by two 10mm bolts. A ratchet wrench or 3/8 drive ratchet with a swivel socket will work. Remove the bolts then pull the fpr off of the rail. It'll take a little effort to break the seal. A small amount of fuel may come out of the fpr once it's removed so have a rag ready.

http://img73.imageshack.us/img73/8467/15417970ls1.jpg

Step 4
Now we remove the two 12 mm bolts which secure the fuel rail with a 3/8 ratchet and standard socket on a short extension. Once they are out, lift out the rail. The injectors will stay with the rail and come away from the motor.

Between the fuel rail and motor are a pair of plastic spacers. Epoxy them into place on the motor at this time.

http://img153.imageshack.us/img153/1346/87035071di7.jpg

everytime I pop the gas cap it helps a bit, pressure gauge says so as well, drops from like 30psi to about 20-25psi.

but the biggest difference is that gas will just drip out a bit when you remove a line instead of shoot out.

Hopefully this will help a little too. This was done back in my infancy before I really knew how to do a writeup.
https://www.miataturbo.net/forums/showthread.php?t=4948