I found this floating around in my Evo 5 engine bay today:



I've had the car for over a year but only just had a proper look at this concoction.

It looks like a Defi boost sensor from a decommissioned boost gauge plugged into what seems to be an old OEM fuel pressure control valve:



I'm not an engine guru, and this is my first turbo so I don't no much about what I'm looking at, I just found what that boost sensor was from checking on the net and figured the fuel pressure valve out because it looked like the one that's currently installed:



This mutant thing is completely disconnected from everything except for one wire heading off into the nether (I assume for the missing boost gauge).

It's not a major, I was just curious to see if anyone could enlighten me?

 

It looks like the vacuum sensor that was attached to the side of your intake manifold. It goes right on top of that round plug on the IM.
It is a part of some vacuum switches which tell the car if their is rail pressure so the ECU can tell if it needs to prime the fuel system before you turn the key to start the car.

 

Are you sure? Which bit are you looking at, the box looking bit or the bit with the adjustment knob and the two electrical prongs?

 

Not the defi thing....the other one with 2 vacuum lines coming off of it

 

Oh ok.
It looks identical to the thing in the third photo, which according to the workshop manual is a fuel pressure control valve. one of its hoses is connected to a fuel pressure regulator on the fuel rail (according to the manual), and the other hose is going straight into the intake manifold.

 

Yep, that's it

 

Ok, cool.

Any idea why someone would plug it into a boost sensor? Trying to use it as a boost control maybe?