What is this part?

We were under the hood on CosworthSTi's 07 WRX last week. We found this item in the pic below in the engine bay(Passanger side, loose by the intake manifold. It appears its suppose to be inline with something. Just wondering if anyone can identify what this part is and if its suppose to be somewhere.




Thanks

 

Its a sensor.


bwahahaha, brb, I'll go take a look under my hood for one.

 

This is where I found mine. 2007 WRX.


Looks like that hose lying over the wastegate (in your picture) is supposed to plug into that sensor.

 

Thanks! I know its a sensor for something. I figure its suppose to be somewhere. Maybe a reason the car doesnt get over 18mpg on the interstate, and like to go to like 25psi or so.

Is that a vacuum or a coolant line it goes into, and does it have lines going out both sides?

Car has the following mods on it(VF39, GMBCS, Turbo inlet, and exhaust). Would it have been removed for any of those mods?

 

It looks to me like its a part of the PCV system or something like that. I know it plugs into that big vent tube. Does the car have a catch-can by chance? Actually, any and all mods to the car would be a help.

 

The only thing I can think of would be that it was removed to install the new inlet.

 

Does that part have something that connects to the inlet?

 

That's the PCV diag connector. It pretty much does nothing on the turbo engines. If you disconnect it, you'll see that the harness plugs into nothing. At the connector, you should find a jumper connecting the two wires. The jumper will fall out if it isn't plugged into the PCV diag connector, so that is probably why someone left it like that. It will throw a code if you remove the jumper.

There is a hose that connects the crank case ventilation to a T junction. One side of the T junction goes to the PCV valve in the intake manifold, the other side of the T junction goes to one of the turbo inlet vacuum lines. The side that goes to the turbo inlet connects right before the compressor wheel. On the stock turbo inlet, the vacuum line is a large "L" shape boss that stands vertically. The PCV diag connector goes inline between the turbo inlet vacuum line (L-shaped) and the T junction, which goes to the crankcase ventilation.

Some aftermarket turbo inlets don't have that vacuum line connector, so people just leave that PCV diag connector as you found it. In other cases where people decide to re-route the PCV system for a catch can setup, they sometimes disconnect the PCV diag connector because it restricts flow or they are using different hoses, etc. The PCV diag connector is supposed to detect when there is a problem with the PCV system, but that is highly arguable because when you look at it closely, it's hard to understand how it works at all. Just be careful not to lose the jumper resting in the harness there.

~Dan

 

So, if its not missing the lil jumper its fine chilling out in the open? Won't cause poor fuel economy or overboosting?

 

no it doesn't do anything - see turbo turtle's post. my car doesn't have that on it anymore (hasn't for a long time)

 

Thanks guys! Just making sure, I didnt think it was important. Its bee off like that since he has had the car and it runs fine.