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View Full Version : RB25 sensor needed?

Darth & Vader
05-16-2011, 11:45 PM
Hey Guys, having an idle problem with my rb so was looking over the iacv and other parts around and connect to it, and noticed a black sensor not plugged it. Not sure what it goes to or if it's needed? Hoping anyone could shine some light.

Here's a video of where the sensor is.


http://i1084.photobucket.com/albums/j401/rb24s14/th_Parts4sale052.jpg (http://s1084.photobucket.com/albums/j401/rb24s14/?action=view&current=Parts4sale052.mp4)


http://s1084.photobucket.com/albums/j401/rb24s14/?action=view&current=Parts4sale052.mp4
Chrischeezer
05-17-2011, 12:00 AM
has the engine always had this problem since day one?
Darth & Vader
05-17-2011, 12:10 AM
I'm going to say no it hasn't, but i've only had the car for about 2 months. I went back to stock turbo, injectors, ecu and i believe it started then or got a bit worse. I did notice it was idling a bit higher than "normal" when it had the bigger turbo and whatnot on it, but thought it could be due to the haltech. If i pinch the hose going from the intercooler pipe to the iacv the idle cuts down real nice and low where it should be. Also, if i disconnect the brown plug from the iacv the idle will also drop down to normal RPM's. Why do you ask?
Chrischeezer
05-18-2011, 10:47 PM
during a diagnostic the history of a car and its problems are helpful. just trying to understand what variables are involved.

at this point there too much going on, it would just me a guessing game unless we were hands on.

guess away..
Darth & Vader
05-21-2011, 12:38 AM
during a diagnostic the history of a car and its problems are helpful. just trying to understand what variables are involved.

at this point there too much going on, it would just me a guessing game unless we were hands on.

guess away..


I'm trying to find out if that sensor is needed and what's it goes to. I have provided a video of the sensor....
Sileighty_85
05-21-2011, 11:30 AM
Thats like a secondary IACV
http://i73.photobucket.com/albums/i235/Neil_85/Miyukis%20Silvia/DSCN2768.jpg

IIRC that plug is located in the Knock Sensor harness/ Lower RB harness
Darth & Vader
05-21-2011, 05:55 PM
Well, i have 3 connectors on that harness. Two of which are knock sensors and the other is a blue colored connector. I would have guessed since the sensor's connector is black, it should be a black connector on the harness, but mine is blue. Nonetheless, here is a pic of the connector that is not being used....Is it this one?



http://i1084.photobucket.com/albums/j401/rb24s14/Parts4sale060.jpg
stamps31757
05-21-2011, 06:09 PM
most of the plugs on our harnesses only plug into one place so its kinda hard to get them wrong.
username
05-22-2011, 01:07 AM
Yeah that blue plug is the correct one.
GSXRJJordan
05-22-2011, 02:46 AM
There's three different plugs down there, they all look the same but one is keyed differently.

The brown plug is the IACV (although they called it the AAC, Auxilliary Air Control or something on the RB25).

The purple plug is something else, forgot, it's been years since I built my Rb25. I didn't wire it in on any of the RB harnesses I've built.

The black plug is a coolant flow control valve, most people don't use it. If that's what's not plugged in, don't worry abou tit.
Fullboost TM
05-22-2011, 03:18 AM
Brown is AAC
Purple is for the A/C
Didn't know there was a third one, but most likely useless.
Sileighty_85
05-22-2011, 10:53 AM
ppl its a secondary air system as you can see from my pic, Its Tee'd from the IAVC pipe

So if that valve is stuck open it will allow more air to enter the IM raising the idle
GSXRJJordan
05-22-2011, 02:35 PM
ppl its a secondary air system as you can see from my pic, Its Tee'd from the IAVC pipe

So if that valve is stuck open it will allow more air to enter the IM raising the idle

You'd have to plug it in for it to be stuck open - at rest it's closed IIRC.
eh?
05-22-2011, 02:50 PM
You'd have to plug it in for it to be stuck open - at rest it's closed IIRC.

No it's open with no voltage. 12V will cause the bimetalic strip to close the valve after a few minutes.
Most RB25 owners have high idle problems because it is not wired up. Connect it to any 12v source.
GSXRJJordan
05-22-2011, 03:29 PM
No it's open with no voltage. 12V will cause the bimetalic strip to close the valve after a few minutes.
Most RB25 owners have high idle problems because it is not wired up. Connect it to any 12v source.

Ah, I remember this now... I did wire this in with the VTC/CAS/Injector +12V wire when I did my harness. Great info, thanks!
Darth & Vader
05-22-2011, 11:40 PM
No it's open with no voltage. 12V will cause the bimetalic strip to close the valve after a few minutes.
Most RB25 owners have high idle problems because it is not wired up. Connect it to any 12v source.

I have i high idle problem on my RB and i hate it! Mine is wired up tho...

Was cleaning my IACV today and noticed next to the adjustment screw, mine has some puddy there. Does anyone else look like this?


http://i1084.photobucket.com/albums/j401/rb24s14/Parts4sale062.jpg
singlecamslam
05-23-2011, 01:07 AM
Mine iacv is not even hooked up, and coolent lines are looped. It idles at 1000 rpm, maybe 1100, how bad is your idle?
Darth & Vader
05-23-2011, 09:26 AM
Mine iacv is not even hooked up, and coolent lines are looped. It idles at 1000 rpm, maybe 1100, how bad is your idle?

Idle is pretty bad (High around 3000RPM). The thing that makes me the most angry/annoyed is that the idles WILL NOT DROP once the engine is warm. I've changed out the Coolant Temp Sensor thinking it may have been faulty and it's still doing the same thing. This RB is giving me headaches ><, I just need it to run properly.

Another thing, i changed the Q45 TPS with a Series 1 TPS, installd it correctly and even checked the voltagese to make sure it was reading properly, but sometimes when i step on it my car just bogs out! Whats going on with my RB? :'((