Alec

Yesterday I was driving my FD and everything worked just fine for hours, until I gave full throttle in third gear and suddenly the engine almost died out. The turbo's wouldn't pull at all and the boost pressure gauge just bounced between -5-10psi.
I drove the car home very carefully and today I have been looking at the problem, the map sensor is correctly connected, no vaccum leak or anything.

When I tried to start the car again today it idles quite good at about 900rpm but as soon as I try to give some throttle a blowing sound appears and the boost pressure gauge just bounces.

My mod's are:
3" exhaust from turbo's and out
HKS open air filters
Re-Amemiya ecu (Have tried the org ecu with no luck)

I am adding some pictures of the spark plugs and the spark plug holes:

It is a blown Apex seal or could it be something much more easy to fix?





In the second picture, is there something missing just above the spark plug holes?

dontlift

I'm betting it will "be something much more easy to fix":
It sounds like you have a major boost leak. Check all the hoses into and out of your intercooler. One of them may have burst or popped loose. Also make sure it is securely attached to the Y-pipe.

rxcited2

Regarding the "something missing" question: both front and rear rotor housings have a tapped hole where the knock sensor is installed. But the FD has only one knock sensor and it is installed in the front housing. So the rear housing tapped hole is meant to be left empty.

Your plugs look like they need to be replaced, but that kind of carbon build up is very common with an FD, particularly a performance enhanced one.

You say you can hear a hiss coming from the engine bay when you are boosting? I agree it sounds like a leak somewhere between the output of the turbos and the top of the engine. That is kind of a general statement, but it literally could be anywhere along the way from the turbos, to the inter-cooler, from the inter-cooler to the intake elbow, the throttle body or the intake manifold. A common place to check is the top on the right side of upper intake manifold. There are a number of nipples there which all should be connected to something and not leaking. There is a big nipple which connects to a hard pipe that runs along the firewall over to the brake assist unit. Make sure there are no disconnections or cracks or holes. There are also a bunch of different nipples in various places around the upper intake manifold. Inspect them all carefully looking for disconnections, cracks or holes.

thiasRx7

I had the same hissing sound and would only boost around 5psi. It ended up being the coupler connecting the y pipe to the crossover pipe. I upgraded to the enfini y pipe and crossover pipe and have had no problems since.

I would check there and the rubber hoses going in and out of the IC.

Alec

But the problem is that I can't find any vaccum leak

Rxcited2: Thank you for clearing up that it's supposed to be an empty hole in the rear housing.
I will replace the plugs and once again check everything that you've listed up!

But could it be something ells than a vacuum leak?

dontlift

We are not talking about vacuum lines. It's probably a boost leak instead. Check all the lines from the turbo Y-pipe to the intercooler and from the intercooler to the elbow. Look for one that has either ripped open or become disconnected.

rxcited2

Alec, you said:

Are you talking about while you are driving or with the car parked? Try opening the hood, with the car running and warmed up, e-brake set and in neutral. Actuate the throttle by pushing on the throttle cable at the throttle body. You'll need to rev it pretty hard to generate boost conditions. Can you detect the "blowing sound"? You need to find where it is coming from. Sometimes it is helpful to take a short length of hose (3 or 4 feet) and insert one end in your ear. Use the other end as a "sound probe" to try to isolate where the sound is coming from.

The Y-Pipe coupler previously mentioned is a good candidate. This is because it is under boost conditions and is about as close to the heat as you can get, being right above the exhaust manifold and turbos. The Efini Y-Pipe upgrade replaces the flexible coupler and plastic crossover pipe with rigid aluminum pipes that hard bolt together. So if you do determine the leak is coming from there, this would be a good way to fix it.